Swapping a transmission output shaft

[black92_tsi_awd]

I need to replace the output shaft on my 5 speed transmission. I lost a bearing in the transfer case and it twisted the shaft splines. Can the trans output shaft be replaced with the trans in the car??? Pulling the trans in the driveway in winter does not sound like fun!

 

[OWGTI]

In theory it can be done if there is enough free space to pull the shaft (about 18 inches). If you have a straight shot out of the tranny that long, then pull the tranny end cap, pull the snapring off the viscous coupler, pull off the VC, be careful to note where the small ball bearing ends up and put it back where it came from, and then remove the output shaft through the bell housing. Installation is the reverse of removal. Dont you hate it when people say that?

Later
Arnie

 

[black92_tsi_awd]

I've only got about 11" before the shaft will hit the pan. I'm going to try removing the oil pan to get clearance to pull the shaft. I'd rather do that than disconnect everything necessary to pull the trans. I see how it goes!
All I know is that I bought the car , drove the car for a week and it's been on jack stands for 3 It was fun when it was running!

 

[OWGTI]

Dude, seriously pull the transmission. It sounds as though you have a fair bit of work to do to it. Pulling the pan unless the engine leaks is a huge PITA that will almost gaurantee a leaking pan afterward. Pulling the trans is no big deal. Sounds like you already have the transfer case off so all you have to do is remove the upper and lower intercooler piping, the shift cables, the speedometer cable, the axles, the slave cylinder, the mounts on the passenger side, and the bellhousing bolts. Should take no more than 2 hours total.

Later
Arnie

 

[4pistons]

I'll bet ten to one those splines didn't twist to failure. Look closely at them. Are they really smooth and shiny? That is caused by a side gear thrust washer failure in the center diff. If they are they wore out. It seems to be pretty common with our center diffs. If the output shaft is allowed to slide in and out, which the side thrust washer controls, it will "file" the splines off sliding back and forth when you get on and off the gas. You have to either rebuild the center diff to fix it or weld it. Either way the tranny has to come out. Check the splines in the X-fer case as they are probably worn too. They'll need too be replaced too.

If the splines actually"twisted" off you'd see jagged, broken splines and metal smeared around the shaft. I'd be surprised if that was the case.

I have a diagram on how to weld the center diff to eliminate the shaft play if anyone wants it. Email me at [email protected]

Rick - '91 GSX - Welded for five years now, no more shaft failure!

 

[black92_tsi_awd]

Update....

The shaft does come out without removing the pan. I pulled the tran end cover off, removed the viscous coupler and the retaining ball. The shaft slid right out clearing the pan. The reduced shaft size at the VC end allows the shaft to angle down missing the pan.

4pistons,
The splines are twisted, there is no visible wear. I think the blown bearing allowed the transfer case shaft to flop around, it moved about 1/8" vertically when I removed it, that movement caused the twisted splines. I did replace both the transfer case shaft and the transmission shaft.

 

[4pistons]

I'm only repeating myself so you do not go through all this trouble and have that shaft wear out and fail again in a year like mine did.

The splines are twisted, there is no visible wear

To "Twist" a spline is damn near impossible. Guys that run 10s and 9s are still using the stock output shaft without "twisting" splines. That shaft would break before the splines twisted. If the splines are smooth and shiny then the splines wore down and THEN failed. I will try to post a picture of what mine looked like after it failed.

The most likely cause for the worn splines is a failed side gear thrust washer in the center diff. It will cause the splines to wear and fail again if not addressed. I'm just re-emphasizing to give you a sereoius heads up to check everything before you think you've fixed it. I hope I'm wrong about your situation. You'll be thankful I pointed it out if I'm not.

Rick - '91 GSX on it's THIRD (and last) output shaft!

 

[black92_tsi_awd]

I appretiate the heads up...beleive me!!
I'd like to see your picture to get an idea of what your talking about, my buddy who races a 9 sec 151mph Eclipse hasn't seen a twisted shaft either. I'll run your suggestion by him, see what he thinks. I plan on dropping the transfer case in a month or so to check for wear.
Thnaks for the info.

 

[4pistons]

Here's the half worn splines on the original shaft that was in the car when I bought it at 88k miles. The shift fork broke on a power shift and I saw this worn shaft when I removed the tranny so I replaced it before it failed.

Here's the failed splines. This is the new shaft after one year!

How does that compare with yours?

This was caused by the worn center diff allowing the shaft to move in and out laterally, and "filing" itself to failure inside the xfer case. The same thing will happen if you don't use the retaining ball under the VC when you reassemble it.

Rick - '91 GSX

 

[black92_tsi_awd]

I don't see any picts....

 

[4pistons]

No pics at all or do you get the little box with the red X in it?

 

[4pistons]

Try to veiw the pics here:
http://www.ofoto.com/BrowsePhotos.j...t_signin=BrowsePhotos.jsp?showSlide=true&Ux=0

 

[black92_tsi_awd]

Your splines look different than mine, take a look here:
http://www.dsmtuners.com/forums/showthread.php?t=156176. I first posted in the newbies list.

I can see in your picts where the splines get real thin form the rubbing, my splines are constant thickness but in a S shape.

 

[4pistons]

WOW!! In the six years I've been wrenching on DSM's I've never seen THAT before! The only way I could see that happening is letting the X-fer case run dry and overheating, to the point of blueing, and then the X-fer case locks up voilently. Whoever did that let it go WAY beyond the first indication of problems as there's no way you wouldn't hear that fried bearing.

You aren't serious about changing that shaft with the trans in the car are you? I wouldn't even think about using that trans or X-fer case without a thorough inspection of the internals. I'd check the rear end, too.

Boy! I didn't think I could see something new with DSM's but I learned different today! Good Luck repairing it. I don't mean that sarcastically either.

Rick - '91 GSX

 

[black92_tsi_awd]

I love surprising people!!!

We tore down the transfer case and everything was fine. We replaced the smoked bearing and the input shaft. The ouput shaft spun fine.

When the bearing went...I heard it alright!! Sounded like a semi was jake breaking in my back seat. Pulled over, I'm sure that's when it seized to the shaft, and limped back home.

Got everthing back together and it drove fine. Got it home and there was a puddle under it. The passenger side axle seal is leaking now.

 

[BISHILVR]

WOW!! In the six years I've been wrenching on DSM's I've never seen THAT before! The only way I could see that happening is letting the X-fer case run dry and overheating, to the point of blueing, and then the X-fer case locks up voilently. Whoever did that let it go WAY beyond the first indication of problems as there's no way you wouldn't hear that fried bearing.

You aren't serious about changing that shaft with the trans in the car are you? I wouldn't even think about using that trans or X-fer case without a thorough inspection of the internals. I'd check the rear end, too.

Boy! I didn't think I could see something new with DSM's but I learned different today! Good Luck repairing it. I don't mean that sarcastically either.

Rick - '91 GSX

actually the exact same thing happened to me on my way to work today...ran fine when i parked it last night, came out today got about three miles down the road at 55mph, came up on a car going 35 so i slowed down and then it felt like 2 cylinders were missing, so i stepped on it to go out around the car and it did fine, came to a stop sign, nothing....drove a few more miles and bang!!! sounded like a semi jake braking in the back seat and the car just acted like my e-brake was on all the way pushed the clutch in, car came to a stop, put the car in first and could hardly move but i forced it so i could limp to work after a mile it loosened up again, then it was moving ok unless i went over 30mph everytime i went faster boom, boom, boom!!! and tons of friction, got to work pulled the xfer case off and the splines were twisted the same way.....fun removing it in a bike shop() couldnt get the exhaust bolts out so i had to pry the mother past the pipe.....fun ........

 

[black92_tsi_awd]

BISHILVR
Did your transfer bearing seize up too???

 

[BISHILVR]

BISHILVR
Did your transfer bearing seize up too???

I would say so, i was at work and didnt want to push my luck messin around with takin it apart, i started to try to take the cover off and broke two of the bolts that hold it on and after they were all out the cover still would'nt even budge!!!...i'll tell you though the gear oil smelled pretty burnt... .......

 

[black92_tsi_awd]

My cover was hard to remove also...had to use a rubber mallet to turn it, hit one of the mounting ears sidways to break the seal. The cover is a slip fit with an oring for sealing. You'll have to get the broken bolt out to remove the cover.

 

[BISHILVR]

My cover was hard to remove also...had to use a rubber mallet to turn it, hit one of the mounting ears sidways to break the seal. The cover is a slip fit with an oring for sealing. You'll have to get the broken bolt out to remove the cover.

i got it apart yesterday, and the rear bearing in the shaft is trashed, it's in pieces and missing some rollers, glad i made it to work after looking at it, and real glad it did'nt leave me out in the middle of nowhere at like 3:00 am or anything, this is why i bought a gst last time.....every piece of the awd system on that car has failed on me and blown to pieces, and i know i'm not the only one, just too much crap to break for me....i'll settle for the fwd power on the roll......

 

[foreverinvayne]

Is it difficult to replace the output shaft in the tranny? how long does it take once you have everything out of theway to get to the tranny? And would I be able to swap a 23 spline for a 22 spline in a tranny? are they interchangeable?