1G Welded Center Diff FWD Questions

[Alex40823]

Hey guys, so I managed to mangle up my spiders gears in my center differential and I was wondering what options I have to keep this tranny running.
First off I have a AWD tranny BUT it's on a FWD car and setup. I have no plans on making it AWD anytime soon unless chances and parts arise but for now It'll be a FWD set up.
Anyway, you guys can see the damage on my spider gear and the cross section. I was wondering if I weld both spider gear and top and bottom gear together to the central diff case itself, is that possible and advisable?
I have replacement spider gear and cross section coming in but I'm not sure if it'll last if I keep launching the car. I was wondering which is better, to replace the parts or weld the old parts together, since I'm only using FWD.
Thanks guys

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[bastarddsm]

Holy shit 10/10 destruction! But yes weld that bi*** and send it. If you are going to keep running it FWD, find a 2g fwd trans. They have closer ratios and drive off 4th gear so it should last longer.

 

[pauleyman]

Hey guys, so I managed to mangle up my spiders gears in my center differential and I was wondering what options I have to keep this tranny running.
First off I have a AWD tranny BUT it's on a FWD car and setup. I have no plans on making it AWD anytime soon unless chances and parts arise but for now It'll be a FWD set up.
Anyway, you guys can see the damage on my spider gear and the cross section. I was wondering if I weld both spider gear and top and bottom gear together to the central diff case itself, is that possible and advisable?
I have replacement spider gear and cross section coming in but I'm not sure if it'll last if I keep launching the car. I was wondering which is better, to replace the parts or weld the old parts together, since I'm only using FWD.
Thanks guys

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How were you running it fwd in the first place?

 

[jdxnc]

How were you running it fwd in the first place?

By the looks of it, the viscous was doing double duty. I've never seen that much damage to a cross shaft. It had to have been slipping a f*** ton to do that. It had to have felt like clutch slip all the time.

If have a fully welded 90 center diff if you happen to have a 90 gearset in the trans, I'll part with it cheap.

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[pauleyman]

By the looks of it, the viscous was doing double duty. I've never seen that much damage to a cross shaft. It had to have been slipping a f*** ton to do that. It had to have felt like clutch slip all the time.

If have a fully welded 90 center diff if you happen to have a 90 gearset in the trans, I'll part with it cheap.

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That was my thought too. Never seen a cross shaft that bad.

I reread this. Sounds like you've been driving an AWD tranny as FWD. You can't do that. It doesn't work that way. A shim didn't fail. That center diff and viscous was doing all it could do but with no rear it just spins until it fails. Likely felt like a bad clutch until you damaged it enough it likely caught some until it finally failed completely.

 

[jdxnc]

I reread this. Sounds like you've been driving an AWD tranny as FWD. You can't do that. It doesn't work that way. A shim didn't fail. That center diff and viscous was doing all it could do but with no rear it just spins until it fails. Likely felt like a bad clutch until you damaged it enough it likely caught some until it finally failed completely.

Yup, the viscous is likely toast too from heat.

 

[Alex40823]

Holy shit 10/10 destruction! But yes weld that bi*** and send it. If you are going to keep running it FWD, find a 2g fwd trans. They have closer ratios and drive off 4th gear so it should last longer.

At first I thought it was an axle snapping during launch but oh well haha

By the looks of it, the viscous was doing double duty. I've never seen that much damage to a cross shaft. It had to have been slipping a f*** ton to do that. It had to have felt like clutch slip all the time.

If have a fully welded 90 center diff if you happen to have a 90 gearset in the trans, I'll part with it cheap.

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I'm not stateside right now but If I do weld my spider gears so I can still use my tranny should I weld it like this?
It's a rough sketch of the center diff but basically the green line is the cross section and red is the welded area
I might have to weld also the cross section where the spider gears go in since theres not much left of it. But Is this right?
It's a fwd setup and I dont have plans on making it awd anytime soon

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By the looks of it, the viscous was doing double duty. I've never seen that much damage to a cross shaft. It had to have been slipping a f*** ton to do that. It had to have felt like clutch slip all the time.

If have a fully welded 90 center diff if you happen to have a 90 gearset in the trans, I'll part with it cheap.

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That's most like why sometimes when I hit boost it feels like a clutch slipping before getting grip, then it finally gave in during a launch

 

[jdxnc]

I'm not stateside right now but If I do weld my spider gears so I can still use my tranny should I weld it like this?
It's a rough sketch of the center diff but basically the green line is the cross section and red is the welded area
I might have to weld also the cross section where the spider gears go in since theres not much left of it. But Is this right?
It's a fwd setup and I dont have plans on making it awd anytime soon

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You remove the spider gears and shaft completely like in my photos above.

That's most like why sometimes when I hit boost it feels like a clutch slipping before getting grip, then it finally gave in during a launch

Exactly, you were destroying the center diff and viscous the whole time. You need a welded center diff or VCU to run an awd trans as FWD.

 

[Alex40823]

I reread this. Sounds like you've been driving an AWD tranny as FWD. You can't do that. It doesn't work that way. A shim didn't fail. That center diff and viscous was doing all it could do but with no rear it just spins until it fails. Likely felt like a bad clutch until you damaged it enough it likely caught some until it finally failed completely.

I reread this. Sounds like you've been driving an AWD tranny as FWD. You can't do that. It doesn't work that way. A shim didn't fail. That center diff and viscous was doing all it could do but with no rear it just spins until it fails. Likely felt like a bad clutch until you damaged it enough it likely caught some until it finally failed completely.

yeah basically since I got this car it's a fwd but the tranny is awd, so the spline that connects to the T case is just there hanging. Any recommendation on what to do till I get a fwd tranny? Is it possible to just remove the viscous since I'm running fwd?

You remove the spider gears and shaft completely like in my photos above.

So the top gear where it connects to a shaft I weld that to the top cover with the bolts
and what about the gear where it sits on the bottom I weld that to the body too? and what about the two side spider gear do I need to weld them to the top and bottom gears?

Exactly, you were destroying the center diff and viscous the whole time. You need a welded center diff or VCU to run an awd trans as FWD.

VCU as in viscous coupling unit right, the drum that sits on top of this spline right?

 

[jdxnc]

So the top gear where it connects to a shaft I weld that to the top cover with the bolts
and what about the gear where it sits on the bottom I weld that to the body too? and what about the two side spider gear do I need to weld them to the top and bottom gears?

VCU as in viscous coupling unit right, the drum that sits on top of this spline right?

Sorry I mistyped, I meant VCE, it's basically the 2 inner splines of the viscous coupler welded together to lock the front and rear wheels together, which accomplishes the same thing as welding the center diff.

 

[Alex40823]

Sorry I mistyped, I meant VCE, it's basically the 2 inner splines of the viscous coupler welded together to lock the front and rear wheels together, which accomplishes the same thing as welding the center diff.

So it’s the top and bottom gears right?

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[pauleyman]

Your viscous coupler will now serve no function but to hold the shaft in place. If you weld a center diff you can't just willy nilly do so. The splines need to line up so the shaft can go through and the Viscous can still go on. The side gears and cross shaft are trash. You don't need them to weld anyway.

 

[Alex40823]

Your viscous coupler will now serve no function but to hold the shaft in place. If you weld a center diff you can't just willy nilly do so. The splines need to line up so the shaft can go through and the Viscous can still go on. The side gears and cross shaft are trash. You don't need them to weld anyway.

I’ll have them welded in a machine shop and just bring the case and shafts so it’s lined up perfectly. So I can basically run the center diff with top and bottom gear welded and no spider gear and cross section?

 

[bastarddsm]

Yes. Put the bottom gear in without the thrust washer, and use a bolt/nut to hold it down and a big millermatic 250 set on burn this f***er down and have at it. Fill 'er in. I usually tack a few spots first which gets some heat in it, then burn it in good. I wrap in a welding blanket after to let cool slowly. Top I usually Tig weld with stainless rod.

you will need to cut a section of spline out of your old viscous coupler to make an output shaft retainer. Or find a plug for the case and don't even install an output shaft.

 

[bastarddsm]

Sorry I mistyped, I meant VCE, it's basically the 2 inner splines of the viscous coupler welded together to lock the front and rear wheels together, which accomplishes the same thing as welding the center diff.

Kinda, but far weaker. If you do something like break a tcase it breaks the spider gears too and spits the pieces out and ruins the gear set.

 

[Alex40823]

Yes. Put the bottom gear in without the thrust washer, and use a bolt/nut to hold it down and a big millermatic 250 set on burn this f***er down and have at it. Fill 'er in. I usually tack a few spots first which gets some heat in it, then burn it in good. I wrap in a welding blanket after to let cool slowly. Top I usually Tig weld with stainless rod.

you will need to cut a section of spline out of your old viscous coupler to make an output shaft retainer. Or find a plug for the case and don't even install an output shaft.

wait what do you mean cut out a section of spline? I thought the small ball bearing holds the output shaft so it won’t fall off?

 

[jdxnc]

I cut a viscous apart and used it as a retainer, or you can install the whole viscous, just make sure the parts are well aligned when you weld it.

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[Alex40823]

I cut a viscous apart and used it as a retainer, or you can install the whole viscous, just make sure the parts are well aligned when you weld it.

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Oh ok so I can run it with or without a viscous as long as theres something to stop it from falling off. I think I'll just put the viscous back anyway thanks man. I'll update here when I get everything back from the shop

 

[jdxnc]

Oh ok so I can run it with or without a viscous as long as theres something to stop it from falling off. I think I'll just put the viscous back anyway thanks man. I'll update here when I get everything back from the shop

Correct. You need something to retain the output shaft.

 

[twicks69]

Or if you are welding the center diff and going to keep it FWD, then remove the output shaft and needle bearing and output shaft seal, and install a freeze plug and epoxy it in to the case. No need for a viscous coupler or retainer of the output shaft if it isn't even being used.

 

[Alex40823]

Or if you are welding the center diff and going to keep it FWD, then remove the output shaft and needle bearing and output shaft seal, and install a freeze plug and epoxy it in to the case. No need for a viscous coupler or retainer of the output shaft if it isn't even being used.

Might do that instead save a bit of weight and less moving parts, thanks

 

[Alex40823]

Here’s a little update on the welded center diff for my fwd setup. So what I did was I had my top gear welded to the top part of the center diff and the bottom gear welded to the center diff housing. I also did what twicks69 said and remove the output shaft, needle bearing and viscous coupler unit, and plugging the output shaft with a freeze plug and have it epoxied to the case since I’m not gonna use it. Saves a bit of weight too.

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