TH400 (2WD): New tail shaft bushings are too tight. Why??

[RaysnCayne]

What am I doing wrong guys?!?

I'm simply trying to replace what I believe to be a worn-out bushing in the tail shaft of my 87 TH400 (305/10 bolt rear) and after two tries, I still can't get the yoke to go in after pressing the new bushing in.

In my first attempt I used the expensive, Durabond GM bushing from RockAuto thinking that'd be a no-brainer and worth the extra $6. I checked before I installed it and it slid over the yoke just fine - maybe even a hair of slop. But after installing it in the housing with a hammer and socket, it would not slide over the yoke. I thought I must've burred it up pretty bad with my cave man install approach. So I took a file to it. Still wouldn't go on.

I ordered a second, cheaper (Pioneer) bushing from RockAuto. It slid over the yoke just fine before install. This time I used my shop press and a block of wood to slowly, "softly" install it. Clean as a whistle after the install. Go to put the yoke in: same deal, won't fit!

Does anyone know what I'm doing wrong or why two good bushings that fit beforehand don't fit after the install?

 

[Matt69olds]

Assuming you can get the yoke to go is, smack the yoke with a rubber mallet. Hit it from the 12:00, 3,6, and the 9 o’clock position. Might have to do it a few times.

If that doesn’t work, you might have to hone the bushing to get a good fit. A wheel cylinder hone is ideal for this job. Go slow, it’s much easier to hone more metal off than to put it back on!!

 

[squaredeal91]

I did one of these on a 92 camaro R4 not too long ago and it was pretty snug. I like Matt's idea of honing. I think I used soft sand paper to get it on.

 

[nvrenuf]

Emory clothe the yoke.

 

[RaysnCayne]

Thanks for the replies guys.
I ended up spending about 20 mins sanding/checking/sanding/checking with some 400 grit sandpaper on a dowel and eventually managed to get it to go over the yoke.
Feels wrong to me to have to sand a brand new part to fit. But oh well. Hopefully it'll work.

 

[Ricko1966]

Thanks for the replies guys.
I ended up spending about 20 mins sanding/checking/sanding/checking with some 400 grit sandpaper on a dowel and eventually managed to get it to go over the yoke.
Feels wrong to me to have to sand a brand new part to fit. But oh well. Hopefully it'll work.

This used to happen too us all the time on VW intermediate shaft bearings,you installed them then reamed them to fit,same with king and link bushings,this was be design. Even had some main bearings that after IDR 3 sets or so I couldn't get the oil clearance where I wanted it to be called cleavite they told me they knew clearances weren't exactly right,but to them it wasn't worth retooling 50 year old equipment for a product that will soon be obsolete. I was working at a machine shop and we were making cranks fit the bearings,or the bearings fit the cranks.

 

[NickTransmissions]

Thanks for the replies guys.
I ended up spending about 20 mins sanding/checking/sanding/checking with some 400 grit sandpaper on a dowel and eventually managed to get it to go over the yoke.
Feels wrong to me to have to sand a brand new part to fit. But oh well. Hopefully it'll work.

It will be fine...I have to sand TH400 and 4L80E sun gear shaft bushings all the time. Its very common as aftermarket bushings are sometimes a little tight relative to factory when installed. As long as you didnt take too much off, it will be good to go.

Your durabond bushing may have gone in slightly out of square which cause the tight fit for the yoke. If you havent put assembly lube or vasoline on the bushing then slide the driveshaft/yoke in for the final time...