Stripped AWD output shaft tonight

[Logue]

While driving tonight my output shaft to the t-case stripped. The car sits as of right now in a parking lot..ugh the 95 Tsi AWD with 193,000 miles it. I removed the t-case and the output shaft still has some splines about 50 percent what it used to be. The T-case looked to be about 25 percent what it used to be. A lot of rust/corrosion on the splines and a missing bolt on the T-case seem to be the culprit from my initial inspection, also it was 28 degrees out and I still can't feel my toes right now. There was no warning other than one odd clunk a couple days ago. That I really didn't pay attention too

So I'm thinking about getting a used T-case with 100 percent splines bolting it back on to the 50 percent splines of the Trans and seeing if I can baby the car to my work/ garage about 35 miles away. Than possibly removing the T-case output shaft and replacing it.

Anyone have any idea on where to find just this output Shaft without replacing the trans? Already thought about calling Dogbox, TRE, etc. in the morning to see if they possibly have a spare. But does anyone else have a spare or point in the direction of one. Thanks!!
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[JackM]

I don't have any good used ones. They are pricey but either I or the dealer could sell you a new one. I also have the 23 spline t-case couplers in stock too if you want a new one of those to match your new shaft.

Jack

 

[Logue]

Thanks Jack, do you know if 91-99 trans share the same 23 spline output shaft. I tried to check CAPS but they don't show you that shaft, The show all the other, input, intermediate, all the gears, no output shaft.

There is a guy that has one but it looks like he has a 1g. So I'm really hoping it's the right shaft. Here's a pic of it.

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[twicks69]

Thanks Jack, do you know if 91-99 trans share the same 23 spline output shaft. I tried to check CAPS but they don't show you that shaft, The show all the other, input, intermediate, all the gears, no output shaft.

There is a guy that has one but it looks like he has a 1g. So I'm really hoping it's the right shaft. Here's a pic of it.

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The 23-spline output shaft is: MD741190 This shaft will fit Late 1990 - 1999 transmissions. The shaft costs $300.00 new after taxes (list price).
The 22-spline output shaft is: MD735643 This shaft will fit 1989 - Early 1990 transmissions.

The 23-spline transfer case drive gears for models between Late 1990-1996 are: MD756514 This will require a full transfer case rebuild essentially, with new tapered roller bearings, and new shims that are installed to manufacturers specifications.
The 22-spline transfer case drive gears for models between 1989-Early 1990 are: MD728246
The 23-spline transfer case drive gears for models between 1997-1999 are: MD756623

The 22-spline transfer case coupler shaft for models between 1989-Early 1990 is: MD726967
The 23-spline transfer case coupler shaft for models between Late 1990-1999 is: MD741189




Your best bet is to use a 1991-1996 transfer case (23-spline receiver with the proper gear ratio for your setup) DO NOT USE A 1997-1999 transfer case without swapping your 58-tooth front differential ring gear (1989-1996) to a 57-tooth ring gear (1997-1999).

I have several used 23-spline spares in good shape with very minimal spline wear, and maybe one 22-spline spare output shaft hanging around the house -- I will need to look if I have a 22-spline one.

I would strongly reccomend replacing both the transfer case coupler and the output shaft, along with the viscous coupler snapring (MD720687) (when you pull off the 5th gear cover and remove the viscous coupler and detent ball to pull the output shaft). Be sure to fully inspect your needle bearing on the output pinion gear (that sleeves the output shaft in your transmission), as it could be a failure point. I would also strongly reccomend having your transmission pulled apart and inspected for a potential center differential cross shaft or spider gear failure as a cause for your damage of the output shaft and transfer case.

 

[Mike1992]

The shaft I sold him came from a 92 AWD 23 Spline Transmission. Looks like it'll work just fine and for $45 shipped you appear to have got a bargain.

 

[Got Grip]

Were you able to limp the car to work on your spare T-case?

This is Tony btw.

 

[twicks69]

That is a good price!

The install is easy. If you have questions, please do a search. I have written at least 2 output shaft/viscous coupler eliminator installation thread responses out there this week alone.

 

[4pistons]

Check out this thread -- http://www.dsmtuners.com/forums/drivetrain-tech/244241-beefy-transfercase.html

>>>99% of the time this happens because ether the shaft or the female splines were rusty<<<<

Not true. It seems this way because when those splines fail there is always alot of rust powder found in the X-fer case shaft. But that is the RESULT of the failure not the cause.

Years ago my output shaft failed and I replaced it thinking the same thing. 16 months later it failed again!! As I removed it the second time rusty powder fell everywhere. How the hell could a hardened steel shaft rust away in 16 months? It can't. When I wiped the shaft clean I noticed that the shaft really wasn't rusted, rather it was coated in rusty powder. There were no rust pits on it, no rust on the end of the shaft, no rust in the root of the splines, nothing.

The cause of the spline failure is a worn out center diff. When the side gear shims (thrust washers) fail they allow the output shaft to move excessively. When you're on and off the throttle the shaft moves in and out of the xfer case and slowly files off the splines leaving rusty dust everywhere.

Grab the output shaft and pull on it. If you can move it in and out more than a few thousandths your center diff is worn. No matter how many times you grease those splines it won't cure the problem. Have you noticed there's no factory service specification for greasing those splines? That's because on a properly functioning center diff it isn't required.

Fix your center diff by rebuilding or welding as I did,( Welding a Center Diff - How and Why - DSM Forums ) or you'll just keep stripping them.

Rick - '91 GSX

 

[4pistons]

Does the output shaft look like either of these? The bottom one is my first one, the top one is the replacement a year and a half later!!

 

[Logue]

Were you able to limp the car to work on your spare T-case?

This is Tony btw.

Update!!

Yes, Tony I was able to install my spare transfer case and limp to the dealership/garage. I received the 23 spline special thanks to Mike!!

After I pulled the end case and removed the VC, witch I had to removed with a puller, really stuck. I removed the old T-case shaft looks identical to the one you pictured. I gave a tug on the old shaft before I removed it. It moved one or two mm in and out. But I have had another AWD and the Output shaft moved the same amount but never had this affect. I fixed the 2 stripped threads on the Transfer Case bolts. Installed the new shaft, it was tight going in. After I installed the ballbearing and VC I couldn't move the output shaft in and out.

I'll be replacing the motor soon, with a 6 bolt. When the Trans comes out than I'll disassemble the trans again and check the center diff and most likely weld it. I read that you welded yours, this is my Daily driver. Just don't want to cause more problems.

 

[4pistons]

I read that you welded yours, this is my Daily driver. Just don't want to cause more problems.

Here's a post I made about 2 years ago. Actually, I've posted the same thing so many times I can't remember!

I do drive on a welded diff ALL the time. But this happened to occur back when my car was basically stock, about 8 years ago. Stripping the splines the second time is what caused me to weld my center diff. It completely eliminates any lateral movement of the output shaft and unlike rebuilding the stock diff with thrust washers that can fail, it will never, and hasn't, happened again. I've had the xfer case off several times over the years and since then there is NO WEAR or rust on the output shaft splines. And I don't even grease them!

Since I welded the diff I have driven over 90,000 miles, every day, (except this year) drag raced, autocrossed, road tripped, and commuted with no ill effects, breakage or horror stories to tell.

Rick - '91 GSX

Your mileage may vary, but my experience has been great with a welded diff.

Rcik - '91 GSX

 

[Mike1992]

Glad I could help out.

I've had a welded center diff for a week now. It's not for everyone, but it sure does help with traction.

 

[Logue]

Update again Twicks if your still out there I know its been a little while but your input would be greatly appreciated. Okay so its 8 months later and 10,000 miles. The splines have stripped out again. So I have talked and called a couple other trans re builders. And I'm trying to understand a few things, and obviously like learning and teaching myself new things.

So, some are saying the side shims on the center diff are causing the wear issues, but some others extremely highly knowledgeable people are saying that is will not fix the shaft moving since it is only held in place by a small ball bearing anyway. So my question, Do the side shims actually affect the output shaft movement, and if so can you explain how?

Also, the output shaft bearing part number I have is MR967457 can anyone confirm this bearing number. And if I were to pull apart the trans apart and have the center diff welded along with replacing this one bearing? What would be the best way to go about replacing the bearing and measuring preload?

Thanks guys.

 

[4pistons]

some are saying the side shims on the center diff are causing the wear issues

They got it!! Scroll up a bit and read my posts on 12-19-2008. I even gave you pictures of my two worn output shafts.

but some others extremely highly knowledgeable people are saying that is will not fix the shaft moving since it is only held in place by a small ball bearing anyway.

They're not highly skilled with a DSM AWD trans then!!
Yes, the shaft is held in place by only a small metal ball, but it is held to the side gear in the center diff. If the side gear moves so does the shaft. That's why worn thrust washers in the center diff kill output shafts.

After I wrecked the two shafts above I welded my center diff Not because I wanted better traction, but I had to stop stripping output shafts!! Welding was the most cost effective way to do it.

EIGHT years later I have had NO output shaft wear and NO problems!!

Rick - '91 GSX

 

[4pistons]

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DSM AWD CENTER DIFFERENTIAL

The output shaft is connected to the side gear (6) by the small ball. You can see if the thrust washer (shim) was worn or missing it would allow that side gear to move back and forth. Since it is connected to the output shaft, it moves too. As it moves back and forth with accel and deceleration it is forced in and out of the transfer case gear and eventually "files" down the splines and they fail. It kills the xfer case gear too.

If you remove those thrust washers and weld the side gear to the center diff case (4) the output shaft can't possibly move. Yes you can rebuild the diff with new thrust washers but when will those fail??? The torrington bearings that Shep and TRE offer seem like a good solution but I think there's machining required to install them. And they didn't have those eight years ago for me to try!!

Rick - '91 GSX

 

[Logue]

Okay, So after doing more research. Most Likely I'm going to remove my center diff. and inspect the side shims and try to just replace the worn shims. I know some have had no problems, but with 200k miles, I daily drive this car way more than I race it, I don't beat it. And I don't want to break axles, drive shafts, popping, skipping, if etc. I would rather do the 4 spider diff. If I had the extra money.

I read another article saying the center diff could be removed with the transmission in the car. Just removing the two outer case covers. Anyone confirm this for a 2g? Also CAPS doesn't list the part numbers for the side shims let alone anything to do with the Center diff at all, does anyone know these part numbers? I found TRE's 4 spider rebuild for $300. But what about just a stock rebuild?

 

[Logue]

Alright I have located these part numbers thanks to Tim in another post. Here's a quote:

The complete center differential is not directly sold as a complete unit from Mitsubishi. It comes in pieces only. Here are the part numbers for a 2G:

Center diff case: MD741919
Pinion gear kit, cross shaft and spider gears: MD733338
Center diff upper cover: MD727551
Center diff cover bolts: MD727552 x 8
Center diff inner tapered roller bearing: MD727860
Center diff outer tapered roller bearing: MD720623
Center diff lower pinion oiling washer: MD741409 -- this part number is for a specific size -- this part needs to be shimmed properly by using the correct thickness part per specifications -- MD741405 to MD741413 are the series of part numbers per thicknesses.
Center diff upper pinion spacer: MD720678 -- this part number is also for a specific size -- this part needs to be shimmed properly by using the correct thickness part per specifications -- MD720676 to MD720680 are the series of part numbers per thicknesses. As well there are three other thicknesses with part number not in series, but they are at the minimum and maximum thickness range of the spectrum and are not as common to use.

I have attached a pic. Are these the correct parts numbers for the picture? These are the bearings I would like to replace.

 

[phunny]

I'm definitely against welded dif for street use

 

[Logue]

Yes, I'm trying to avoid it.

 

[Logue]

Well, I have figured it out. Looks as the thrust washers/side shims inside the center diff were worn out. This was wearing the output shaft. And finally so much play between the spiders broke the cross shaft and mangled the spiders. I honestly can't believe it went as far as it did and nothing came out the side of the trans.

So another center diff is on the menu. I'm getting it out of a 98 gsx this should be swappable right. Just the front differential is the one that needs the transfer case be swapped also.

 

[twicks69]

Yes, you can use the 98 center diff case with no problems.