Welding V/C or Center diff opinions, and welded diff handling...

[sbiggi]

I have a few questions for you. For one since you drive your car yr around in Colorado, what kind of premature wear or tear or undue stress do you get on your drivetrain, tires etc with that welded CD?

I drive it year round, but its usually broken a fair amount of the year, .

Havent noticed anything wearing out, but almost everything has been replaced already on the car. If something was wearing out faster, I probably wouldnt know since things break any ways at my power level.

Did you already have the rear sway bar when you welded the diff?
Now that you've gotten used to welded diff and learned how to drive with it properly, how do you feel your handling is in comparison to when it was open diff. Some people say its not that bad, and that its more consistent since the VC isnt playing around with your power bias thru the tires in a corner.

I had the same suspension setup and driven it with and with out the welded.
It handles noticably better without the welded center. I'm not road racing it, so I cant really give a good description. I just dont push it in corners because you will either understeer, or you'll have to power on oversteer.

Yea sucks you broke that stuff, what power were you seeing when you broke 3rd gear?
And Ive never heard first hand of first gear breakage, though i know its happened in plenty of high powered cars. I take it you were in a launch?

I was on my 91 octane street tune, put down 420whp which was good for 122mph traps. I actaully didnt launch when third broke. It got damaged on a 2nd gear shift and let loose at 125mph or so. That was a mess of gear oil on the car.

But, that was the original gear set from my car, and had ~175k miles on it. 150 time slips from the track, and who knows how many on the street.

 

[Black_Bullet]

I ran a TRE Center spool for about half a year in my DD and I hated it. It was horrible for driving slowly and even thinking about turning, it hopped all over the place and I'm pretty sure that it helped destroy my center shaft and transfer case from all the extra stress (stripped the center shaft and input gear of the transfer case.

I just got a new TRE stage 3 with a 4 spider center diff and I couldn't be happier that my car is normal again.

Its funny most people are either far left or far right with this whole welded diff thing as far as whether they like it or not...

Ive never heard of a tcase getting destroyed from doing this. That sucks...

Did you notice a change in traction with going back to open diff?
Say like if you launch did 60ft times suffer or your overall times?

 

[Black_Bullet]

I drive it year round, but its usually broken a fair amount of the year, .

Yea this is exactly what Im not trying to deal with on a DSM.
I like mines running somewhat reliably ALL year.

Hey at any rate how many miles do you put on yours a yr would you estimate.

For more useful info for the thread, a day ago or so I had emailed Jon at Tre regarding this topic to get some more proffesional input on welding the center diff on a daily drive and this is his response.

[Jon]

It's good for drag racing but it's hard on the output shaft, transfer case, driveshaft, ring & pinion and axles.

For long tern daily driver, gotta get back & forth to work everyday reliability... I'd use a 4 spider but if you don't spend all day trying to make full lock turns, which will only piss off the above mentioned parts you should be ok either way.

So yea you welded diff guys, no 'full lock turns' as this does stress out the rest of the drive train a little bit under given circumstance Jon mentioned.

 

[sbiggi]

Yea this is exactly what Im not trying to deal with on a DSM.
I like mines running somewhat reliably ALL year.

Hey at any rate how many miles do you put on yours a yr would you estimate.

I put 7K miles on it in 7 months this year.

 

[JayRolla]

Yea this is exactly what Im not trying to deal with on a DSM.
I like mines running somewhat reliably ALL year.

Hey at any rate how many miles do you put on yours a yr would you estimate.

For more useful info for the thread, a day ago or so I had emailed Jon at Tre regarding this topic to get some more proffesional input on welding the center diff on a daily drive and this is his response.



So yea you welded diff guys, no 'full lock turns' as this does stress out the rest of the drive train a little bit under given circumstance Jon mentioned.

See even Jon agrees that the drivetrain doesnt like it welded up.

 

[Black_Bullet]

See even Jon agrees that the drivetrain doesnt like it welded up.

So Ill summarize what I am getting from all of my welded diff research-

Welded diff Pro's-
Overall better traction, better launches and better 60fts
A more consistent feeling car since theres no center diff modulating power
No worry of breaking spider gears in diff and further damaging transmission
Easier to do donuts or swing rear end out ( if you like toying around)
Less likely to get stuck in the mud/snow- ''true 4wd mode''
more "ideal" for a drag/ straightline Dsm

Welded diff Con's-
Lose of turn radius, thus more difficult to execute U turns
Noticeable lose of handling cornering ( more in corner understeer & on power oversteer)
more rear cv axle, tcase, output shaft wear ( Only if you do a lot of full lock turns)
More rear tire wear ( if you dont have sticky enough tires to prevent skipping/hopping etc.)
more likely to strip or blow out 3rd - 4th gear as there next weakest links in tranny
not "ideal" for a street car driven daily

Yea so I think that about covers it. Anyone like to add anything to that.

 

[JackM]

Yes, welding the center diff would be the best solution for you IMO. The cross-shaft, spider gears, and thrust washers are probably badly worn due to the towing incident, so the center diff guts might be about ready to fail anyway. Popping a VCE in there will just put more stress on the parts and break them sooner as mentioned above.

I road race my 1G a lot (almost every weekend). I have a welded center and agree that you get more of a consistent feel out of it. I don't do the small SCCA solo parking lot deals where I'm sure it is terrible in that World, but on the 1 mile or larger tracks they seem to work well when you are at speed. I have been thinking of going back to a 4-spider, but I remember the days of the ass end whipping around and going off-roading, so I may stick with the welded...

After many laps at CSP here in Colorado, I decided to take some lessons from Mike who I have been getting to know out there to see if he could help with my brake problems. Here is a video of my 1G at the track. You can't tell the center is welded in this place...

Lessons from the Go 4 It school at CSP in Golden C- Video

If you want to lock up your center diff, weld it. Locking it up with a VCE will focus the stress on only a few of the spider gear teeth and they will not rotate to spread the load. If you don't like the welded center, then get a 4-spider later when you can afford it. Running a VCE or leaving it like it is will mostly likely trash your trans in short time. You also want someone with the right equipment and know-how to weld the diff. Just welding it through some unknown shop will most likely cause the lower housing to be warped or the outer lower housing gear to lose its strength if they weld it too hot. I have a JIG and TIG that I use here with proper heat cycling to ensure a quality weld and no outer gear tooth damage.

If you are on a welded center and spinning tires you will go through gears in a hurry. When we have that issue we run slicks. It's not worth it to be slower, spin, and break gear teeth. Running slicks will soften the shock load and prevent wheel spin which will allow gears to last longer and you to be faster.

A welded center really does wear out parts in the drivetrain faster. Think about it. Tires that are under so much stress that they skip when turning. That is some pretty serious stress on the system. My brother put 120k miles on a welded center GVR4 car. The front diff sun gear pin was gone, drive-shaft broke in 3 places, he went through CV shafts, and burned through tires in about half the time they would have worn if he had a VCU center. For those that think that drivetrain stress is reduced by stickier tires are wrong. You are putting the system under more stress and the tires are still skipping you just can't hear it as stickier tires are usually a lot quieter when traction is lost. I have also seen 4-bolt rear diffs fail at the sun gears and VCU due to the added stress of welded centers as well.

I disagree that a welded center will break 3rd and 4th gears. They break due to shock load or just too much power on old parts.

Jack

 

[Black_Bullet]

Yes, welding the center diff would be the best solution for you IMO. The cross-shaft, spider gears, and thrust washers are probably badly worn due to the towing incident, so the center diff guts might be about ready to fail anyway. Popping a VCE in there will just put more stress on the parts and break them sooner as mentioned above.

Yea Im pretty much going to go thru with it now, if I end up not liking how my car handles oh well I guess Ill get over it or either man up and get a 4 spider one day. Say if I did get the 4spider down the road, will I have to get a whole new center diff to go with that 4spider since my current one will be welded, or is it all one piece?

But yes this does seem like the best option for the current momment.
This cars daily driving duties are about over with anyways so whatever.
Id say another year tops as a true DD, Im getting a bike in a couple months that will be used to get to school and work only pretty much which arent far from my house but it would still take a good bit of miles off the DSM.
The later down the line ima buy a little 4cylinder truck for DD.

I road race my 1G a lot (almost every weekend). I have a welded center and agree that you get more of a consistent feel out of it. I don't do the small SCCA solo parking lot deals where I'm sure it is terrible in that World, but on the 1 mile or larger tracks they seem to work well when you are at speed. I have been thinking of going back to a 4-spider, but I remember the days of the ass end whipping around and going off-roading, so I may stick with the welded...

The rear end swings out on you with the open diff or welded?
I recall about a yr ago *( the only time I ever wrecked my car.)
back when I used to drive a lot more aggressively, me and my friend with a 04 sti always used to like pushing our cars hard down these real curvy back roads and one day I went into the corner too hard on a cold night which was a no no since this little 16g used to boost spike back then in cold temps, plus the tires probably werent as hot as they should be and I remember my rear end just swinging out on me completely and I tried to do what I could do get out of the drift but I suddenly felt the vicous make the rear tires get grip again and I just dashed off the road, bounced over the curb and spun out on grass luckily not messing anything up but my alignment.
With a welded diff maybe this situation would've been more controllable?

After many laps at CSP here in Colorado, I decided to take some lessons from Mike who I have been getting to know out there to see if he could help with my brake problems. Here is a video of my 1G at the track. You can't tell the center is welded in this place...

Lessons from the Go 4 It school at CSP in Golden C- Video

Nice, really looks fun. I think id rather do that due to the speeds you get to and open playing field vs the tight slow, narrow transitions in autox.

If you want to lock up your center diff, weld it. Locking it up with a VCE will focus the stress on only a few of the spider gear teeth and they will not rotate to spread the load. If you don't like the welded center, then get a 4-spider later when you can afford it. Running a VCE or leaving it like it is will mostly likely trash your trans in short time. You also want someone with the right equipment and know-how to weld the diff. Just welding it through some unknown shop will most likely cause the lower housing to be warped or the outer lower housing gear to lose its strength if they weld it too hot. I have a JIG and TIG that I use here with proper heat cycling to ensure a quality weld and no outer gear tooth damage.

Im glad I do research before just listening to what someone else says, or if not Id probably be driving around with a welded VC right now.

If you are on a welded center and spinning tires you will go through gears in a hurry. When we have that issue we run slicks. It's not worth it to be slower, spin, and break gear teeth. Running slicks will soften the shock load and prevent wheel spin which will allow gears to last longer and you to be faster.

I can picture what your talking about, but can you elaborate more?
I mean, I figure a car that can blow all four tires away on rolling pulls WITH a welded diff is powerful enough to literally strip teeth off of gears anyways.
But how, why would slicks help/ prevent damage at this point? My impression of adding more grip is sending more shock/ stress thru drivetrain thus breaking much faster.
The only thing in the drivetrain ive ever heard of that benefits you running slicks for not spinning is the tcase, but I cant remember why that is.

I dont plan to OD with this car, just 400-450 to the wheels tops, with very thoughtful and soft driving, I dont like to rag on my car, so Im hopeing my drivetrain can withstand that.

A welded center really does wear out parts in the drivetrain faster. Think about it. Tires that are under so much stress that they skip when turning. That is some pretty serious stress on the system. My brother put 120k miles on a welded center GVR4 car. The front diff sun gear pin was gone, drive-shaft broke in 3 places, he went through CV shafts, and burned through tires in about half the time they would have worn if he had a VCU center. For those that think that drivetrain stress is reduced by stickier tires are wrong. You are putting the system under more stress and the tires are still skipping you just can't hear it as stickier tires are usually a lot quieter when traction is lost. I have also seen 4-bolt rear diffs fail at the sun gears and VCU due to the added stress of welded centers as well.

Would you say in your case that the welded diff made wear much more noticeable, or is it something you just "know" is happening without any negligable damage to account for?
Do you agree with what Jon at Tre said about the "stress" of the welded diff generally only occurs when turning with the steering wheel at full lock?

 

[JayRolla]

Yea listen to Jack he knows his shit. I wasnt saying it breaks 3rd and 4th, just that once you weld up the diff the next weak link are the gears. Im surprised Tyler doesnt rip those things apart in his car.

 

[JackM]

VCU center will tend to over-steer, welded will under-steer.

Slicks help because they are made to resist shock load. Look at a drag car taking off at the line in slow motion. You will see the slick wrinkle at the side wall which helps a lot. The added traction is just an added benefit. You think a car that has spinning and hoping on street tires is better for the gears? Shocking the system hard when shifting or launching makes you slower and look like an idiot ricer Honda owner trying to get his front wheels to spin while shifting to make it look fast. That's probably the worst thing you can do to a trans. If you have enough power to spin while in 2nd or higher gears you will fatigue the gears over time and they will break. That's all part of having a lot of power and racing. You WILL break something. Those that complain that they go though gears every few months are normally the ones that spin or wheel hop all over the place and use old used gears. If they would run slicks and use new gears they would get at least a season out of the gears if not more.

Tyler, an employee of mine, can get away with 700hp at 6k ft elevation because he is smooth. He shifts so fast that it sounds like an automatic, but he is smooth with it. The trans doesn't see any shock loading at all and his trans seems to run forever because of it. I have never broken anything in any of my cars either and another customer of mine with the same power ran low 10s all year in his car and has had his trans without issues for 3 seasons now. He also shifts and launches very smooth. Tyler , awhile back, did break his 2nd gear. He broke it when he was on street tires and shifted into 2nd hard spinning the tires all of the time. It did it for a long time, but the gear finally fatigued and broke from the constant shock loading. He learned to be smoother with it and take away the shock loading and he has been faster and not had a gear issue since.

Like I mentioned above, my brothers GVR4 which had a lot of miles on a welded diff showed all kinds of nasty wear in many weird spots when we tore his car down. It will wear parts faster, period.

Jack

 

[JayRolla]

Well thats some good info. Thanks Jack

 

[Black_Bullet]

VCU center will tend to over-steer, welded will under-steer.

I can see that, but I picture the car "sliding/drifting" out more with welded diff than VCU.

Slicks help because they are made to resist shock load. Look at a drag car taking off at the line in slow motion. You will see the slick wrinkle at the side wall which helps a lot. The added traction is just an added benefit. You think a car that has spinning and hoping on street tires is better for the gears? Shocking the system hard when shifting or launching makes you slower and look like an idiot ricer Honda owner trying to get his front wheels to spin while shifting to make it look fast. That's probably the worst thing you can do to a trans. If you have enough power to spin while in 2nd or higher gears you will fatigue the gears over time and they will break. That's all part of having a lot of power and racing. You WILL break something. Those that complain that they go though gears every few months are normally the ones that spin or wheel hop all over the place and use old used gears. If they would run slicks and use new gears they would get at least a season out of the gears if not more.

That is awesome info and completely opposite of what Ive always thought when it comes to running slicks on these AWD drivetrains! Drag radials doesnt sound as such a bad idea as they did before now.

Tyler, an employee of mine, can get away with 700hp at 6k ft elevation because he is smooth. He shifts so fast that it sounds like an automatic, but he is smooth with it. The trans doesn't see any shock loading at all and his trans seems to run forever because of it. I have never broken anything in any of my cars either and another customer of mine with the same power ran low 10s all year in his car and has had his trans without issues for 3 seasons now. He also shifts and launches very smooth. Tyler , awhile back, did break his 2nd gear. He broke it when he was on street tires and shifted into 2nd hard spinning the tires all of the time. It did it for a long time, but the gear finally fatigued and broke from the constant shock loading. He learned to be smoother with it and take away the shock loading and he has been faster and not had a gear issue since.

Makes a lot of sense. So this goes with my thinking that NLTS is actually BETTER for your gears/trans?

Like I mentioned above, my brothers GVR4 which had a lot of miles on a welded diff showed all kinds of nasty wear in many weird spots when we tore his car down. It will wear parts faster, period.

Yea guess I will just take it easy with turning/ avoid U-turns if at all possible, and avoid full lock turns.

Thanks for all the info really learned some stuff in this thread.

 

[JayRolla]

Yea cant get better info except from Jack. He is a genious when it comes to these trannys. It makes a lot of sense that drag slicks would help the tranny on shifting, but not launching. Shifting into the next gear is always hard when the tires are spinning and you can feel the gears not wanting to let it shift.

Launching you see a lot of people breaking t-cases.

 

[Black_Bullet]

Yea cant get better info except from Jack. He is a genious when it comes to these trannys. It makes a lot of sense that drag slicks would help the tranny on shifting, but not launching. Shifting into the next gear is always hard when the tires are spinning and you can feel the gears not wanting to let it shift.

Launching you see a lot of people breaking t-cases.

Yea IM sure launching is just hard on everything period.

 

[JackM]

DSMlink NLTS can be very hard on the trans if it's not set up right. You want the RPM on the NLTS to match the next gear so you have a smooth transition to that gear. If it's off by too much then you are putting the trans through a lot of stress.

NLTS without the proper management system will destroy a trans. Having the engine bounce off the limiter and then have the clutch shock load the system to the next gear is just stupid and will break a lot of parts.

Jack

 

[Black_Bullet]

DSMlink NLTS can be very hard on the trans if it's not set up right. You want the RPM on the NLTS to match the next gear so you have a smooth transition to that gear. If it's off by too much then you are putting the trans through a lot of stress.

NLTS without the proper management system will destroy a trans. Having the engine bounce off the limiter and then have the clutch shock load the system to the next gear is just stupid and will break a lot of parts.

Jack

Care to elaborate any further.
This is important to me because I actually NLTS ALL the time whenever doing a pull.
Ive never heard of anyone breaking anything from it, and I can actually get into my 3rd gear
(which is old/banged up) easier with doing a NLTS versus shifting regular.
Actually my shifting overall feels smoother and easier in all gears when doing NLTS, and the car accelerates quite a bit faster when doing it, even on a 16g.

I dont have DSMLINK but I have reburnable eprom chips, and I burn my own at my home computer using the evilscribe program. My NLTS is setup at 6k rpm, and I shift my car at 7k in 2nd gear up. Normally I shift fast enough that the revs dont have a chance to fall back down to 6k before I have the clutch back up, but in 3rd gear my shifting is slower and it bounces off the rev limiter sometimes there. Though I shift moderately fast, I am by no means hard on my gears, 85 percent of the time I drive this car like a granny.

What rpm/ technique would be best when using NLTS for fear of breaking something?
What would break from doing a NLTS, a gear? Is NLTS more so a threat on a real high powered car? I am only on a evo316g setup, Im not making much power or anything yet only about 320awhp on 93 octane and Id estimate on this motor/setup with 400awhp on e85.

 

[JackM]

The only thing I can see is the NLTS, even though it is a little high, (it should be close to the RPM of the next gear) there might be enough load taken off to prevent damage. What you are doing is still far better than having no program and having the engine sit off of the factory limiter.

Another thing that comes to mind is your clutch might be weak enough to be able to slip (not shock load the system too much) when under power so it won't break anything and help cushion the load a bit.

I would think if you did the same with a more aggressive clutch like a twin that you could break stuff.

I'm not sure though as everyone drives differently.

Jack

 

[Black_Bullet]

The only thing I can see is the NLTS, even though it is a little high, (it should be close to the RPM of the next gear) there might be enough load taken off to prevent damage. What you are doing is still far better than having no program and having the engine sit off of the factory limiter.

Another thing that comes to mind is your clutch might be weak enough to be able to slip (not shock load the system too much) when under power so it won't break anything and help cushion the load a bit.

I would think if you did the same with a more aggressive clutch like a twin that you could break stuff.

I'm not sure though as everyone drives differently.

Jack

So your implying that its really hard when you do a NLTS with it setup at some random HIGH rpm rev limiter point thus bouncing off the rev limiter, then banging it into gear shocking that gear since nlts is similar to clutch dump launching ( to that gear at least?)

I dont ever grind my gears when I shift, I shift pretty smooth and I pause normally when I go to 3rd gear since its a little banged up from previous owner and doesnt like to exactly hit the syncros easily.

My previous clutch setup did slip a lot it was only a 2100 and I couldnt launch with it anymore after I installed cams and fp manifold. Drove my car for almost a year with no launching because of it, though I still did NLTS on every pull just about.

I will have to keep what you said in mind at least as now I have a ACT2600 and South Bend straight Kevlar disk I just recently got in the tranny and it grabs a lot harder. Maybe when doing the NLTS if what your saying is truely a threat, then perhaps letting the clutch up slow ( slipping) instead of just side stepping during the shift will take a lot of shock load off that gear?

On a good note, I have changed my fluids from pennzoil syncromesh to running straight Redline lightweight shock proof blue. The only thing I fear/regret is ever running straight syncromesh for so long ( almost 2 yrs.) didnt know any better. Funny thing is I used to always assume I was shifting so much better with the thin syncromesh and I wanted that since my tranny is a bit notchy in 3rd gear, but hell so far Im shifting just as easily with the Redline...

Perhaps the Redline shockproof blue will make this tranny survive a lot longer, Id like to get another year out of it at least with no issues while DD and occasionally going to the track to run mid 11s.

 

[JayRolla]

A lot of times when you put the redline stuff in on an old tranny they dont like to shift and get real stiff. I run OEM fluid now that Jack told me thats the stuff to get. Plus he buys barrels of the stuff so I can get it at a discount.

 

[Black_Bullet]

So the center diff is welded now. Wish I had pics of the damage.
Thrust washer was fvcked, V.C. didnt have much resistence, and center diff housing was missing a bolt ( due to a local builder of this trans) who for other reasons Id never go to again.
So at any rate sounds like my center diff was on its way out anyway like I originally expected. Likely more so due to the enfuriating tow incident I had back in Sept.

Well not trying to think about that, so anyways the car is manageable with this welded diff, doesnt bother me. I think this is just another one of those things were people complain and exaggerate shit like little girls, its really not that bad.
With the research ive done in this thread I am just making sure I dont turn the wheel full lock, meaning in tight spaces (i.e. parking lots Iam doing a lot of 3point turns, it really doesnt take that much longer to park.)

 

[Black_Bullet]

Handling wise the car does under steer more, it nose dives into corners more aggressively, and then has this weird outward drifting feel to it like the front tires are literally sliding towards the outside of the corner with power. On sharper corners with enough power applied it slides/scoots the rear tires rather than skipping them in my case. There is definitly more effort to even try to accelerate at all with wheels turned when reversing and for experiment sake I tried to turn at full lock and felt like the rear of my car was hooked to a anchor. My driveway is L shaped so car almost died on me pulling into my garage without giving it gas. I will have to starting doing wider turns.
Overall I can manage with this, I dont corner fast anymore anyways, and new aquired method parking and entering/exiting my garage/driveway, thats about it.

Launching, well I still havent learned technique with this quick engaging 2600 and my current mods, plus it was 40 degs last night, tires were likely cold, so launch wise I couldnt help but to spin all 4s all the way thru my 2step launch, felt kind of ridiculous.

 

[1fastlaser]

ive always ran welded diff trans in my car. Now the car isnt so much a daily anymore and just a weekend car. Sucks my new setup is a gt4294. The 4 spider is tempting to try, but now it seems im going into territory past the 4 spiders reliabilty. I do cruise the car alot on the weekend. Sometimes putting 200 miles on it.

 

[Black_Bullet]

Still working on getting it to hook even with this welded diff .
I preload all my launches with the ebrake btw.

 

[Jeff99GS]

My main reason against it is Jack as Jacktransmissions.com said the drivetrain parts get double the stress when cruising. He said it wears out the drivetrain parts at double the rate.

This is VERY TRUE....take for instance a 4x4 Jeep Cherokee. They have PART time 4X4 with NO center diff....That is WHY it is called PART TIME.
NOW the Grand Cherokee comes with availale AWD....the AWD transfer case has a center diff. The center diff is what makes it able to be ALL TIME 4x4 instead of part time.

It says Right in my manual for the Jeep. DO NOT operate 4 wheel drive On High traction surfaces....Like Dry Roads.

With the Center diff welded it will create BINDING in the whole drive train. Something has to slip.

Try turning a jeep in 4x4 on dry asphalt. HOP HOP HOP.

Welding the center diff is basically like having a JEEP or other 4x4 in Part Time 4x4 all the time....which is fine if you're GOING straight. But harsh on the whole driveline when turning in HIGH traction situations.
ASK anyone who is familiar with Jeeps or 4x4's. They will tell you the SAME.

 

[Black_Bullet]

You can do regular street turns with the welded diff without binding , skipping or hopping, just turn wider and literally feel it out. From what ive experienced with this so far is the only time its a bi*** is when turning the wheel while in reverse. Ive heard and felt the binding then, and the axles will click, but now I just figured out a new technique with that also to avoid that stress on the system. Basically taking more time to drive/park the car which will prolong parts vs someone with a welded diff car who is driving it like a normal car.
Theres plenty of guys getting 5 yrs or more with welded diffs claiming they havent broke anything.