Changing Tail Shaft Bushing

[Detroit Iron]

I wish I could do things ONE f-ing time and be done, but no....

I rebuilt my 904... including the installation of a new tail shaft bushing. And.... I have a brand new Denny's drive shaft which has a brand new slip yoke.

I got everything put together and drove the car maybe 10 miles..... and there's a vibration at speeds above 40 mph. So I go under the car to make sure the u-joints are in the yoke properly, check pinion angle etc. and see ATF drips from the transmission tail shaft at the yoke. I grab the drive shaft, shove up and down, and there's play between the tail shaft and the slip yoke.

So I'd like input on a couple things.

1) How do you think this issue came about? Do tail shafts go bad? Was the bushing I used bad?

2) What's the best way to change the tail shaft bushing now that there's an output shaft in the center of it?

 

[67Dart273]

What is year, make, model?

Run over to MyMopar.com and download a service manual, free

There is/ was a Chrysler tool for that

It is not a huge deal to yank the tail housing. You'll have to drain it or at least part of it, support the trans AKA 2X across the pan and support under, and pull the crossmember. There's a small cover in the tail , two screws, which opens a slot to get the snap ring out of the rearmost ball bearing. A few bolts and it will come off.

 

[Detroit Iron]

What is year, make, model?

Run over to MyMopar.com and download a service manual, free

There is/ was a Chrysler tool for that

It is not a huge deal to yank the tail housing. You'll have to drain it or at least part of it, support the trans AKA 2X across the pan and support under, and pull the crossmember. There's a small cover in the tail , two screws, which opens a slot to get the snap ring out of the rearmost ball bearing. A few bolts and it will come off.

This is my '67 Dart.... 360/904 out of a 1975. So, I'm wondering if the tailshaft is bad. Maybe had a bad bushing years ago and never addressed. Like my posting says; when I built the trans I put in a new bushing.

 

[Detroit Iron]

I'm pulling the tailshaft housing now....

 

[autoxcuda]

If you just put a new one it's going to give you the same result.

There's some other root cause.

 

[Detroit Iron]

If you just put a new one in. Just putting another is going to give you the same result.

There's some other root cause.

Exactly. But it's gotta come apart anyway, so getting that done now.

 

[Lefty71]

I wouldn't replace anything just yet. Now that you've got it apart, get some measurements on that yoke and on the 10 mile bushing. You surely did'nt wear something out that fast. Is the old bushing gone?? Would be handy to compare on that yoke.

 

[Detroit Iron]

I wouldn't replace anything just yet. Now that you've got it apart, get some measurements on that yoke and on the 10 mile bushing. You surely did'nt wear something out that fast. Is the old bushing gone?? Would be handy to compare on that yoke.

True. Will post my findings.

 

[autoxcuda]

micrometer reading of driveshaft OD.

Even just a good caliper reading of installed bushing ID. Bore gauge better but not common to have.

 

[Detroit Iron]

I edited the original post to add video of what I'm seeing.

 

[67Dart273]

Also check the yoke and shaft splines carefully. I've read that some trans, you can (wrongly) install the newer yoke off an OD trans, but the splines are different and they don't fit correctly. I have no idea what to tell you to look for

 

[autoxcuda]

Also check the yoke and shaft splines carefully. I've read that some trans, you can (wrongly) install the newer yoke off an OD trans, but the splines are different and they don't fit correctly. I have no idea what to tell you to look for

YES. I know someone that happened to. Drove him nuts.

The spline count is the same. But the spline geometry is just a little different. If you have a spare old yoke it would really help.

 

[Lefty71]

I edited the original post to add video of what I'm seeing.

Both the bush and the yoke have been changed from the original, certainly possible theres a mismatch of sorts.

 

[tjpatte]

Looking at your video mine moves up and down more than that without issue. While I do have a 727 I think the basic principle is the same.

 

[Bewy]

Some yokes have a plug in them, like a freeze plug. Make sure that is not causing the leak.

 

[Detroit Iron]

I got the tailshaft pulled today and was able to get some measurements.

Bushing ID 39.07mm or 1.5385"
Slip Yoke OD 39.46mm or 1.5535

 

[Kuz]

Something looks funky with those measurements. The yoke is .015 larger than the bore in the bushing? You wouldn't be able to get the yoke in/out with those dimensions.

 

[Detroit Iron]

Something looks funky with those measurements. The yoke is .015 larger than the bore in the bushing? You wouldn't be able to get the yoke in/out with those dimensions.

Right.... remeasuring....

 

[Detroit Iron]

Sorry head up *** over here. Must be the heat....

Bushing ID 39.71mm or 1.5633"
Slip Yoke OD 39.58mm or 1.5582"

 

[Detroit Iron]

I'm looking through my FSM now to see if it indicates with the maximum clearance can be.

 

[Detroit Iron]

An AI search says the tolerance between the slip yoke and the bushing should be three thousandths of an inch. And if I'm doing the math correctly, I have five thousandths of an inch.

So, that's where I'm totally confused. As I stated, everything is new. I will call Denny's tomorrow and give them the OD measurements of the slip yoke. Just to make sure I have the right unit. The splines fit snug, so I'm not thinking it's an over-drive unit. If there's anything off it's just the OD not the splines.

My other thoughts are maybe this bushing is either a mis-box, or Chinese junk. I don't totally remember the brand, but I thought it was ATP. Anyway, I do have another one of those inbound.

 

[Kuz]

I believe there's an oil hole in that bushing that needs to line up with a recess in the top of the housing. Is it oriented correctly?

 

[Detroit Iron]

I believe there's an oil hole in that bushing that needs to line up with a recess in the top of the housing. Is it oriented correctly?

Yes, the bushing is in there correctly. Good point though. I was hoping I installed it wrong and it ran dry and failed right away. Not the case. The bushing looks healthy.

 

[Kuz]

With any luck it's a bad bushing and the new one will fix your clearance issue. While you're waiting for it to arrive, I'd take a few more dimensions. Check the bushing in a few places around the ID, 12:00 to 6:00, 2:00 to 8:00, 4:00 to 10:00, etc.. You're looking for out of round. Do the same on the yoke. Then measure the other end of the yoke as well to check for any taper in the yoke.

 

[67Dart273]

That's only .005" if measured correctly. That is hardly cause for a lot of slop and leakage. I would try again. Remove the seal, stick the yoke partway in, and try it with feeler gauges