Tranny main drive gear (input shaft) wobble

53a1 · Post by **53a1** » Sat Jan 02, 2010 12:04 am

I've been trying to read up on how much play the input shaft to the tranny should have and I'm staring to suspect my tranny case and bearing are worn. The input shaft to the tranny moves up and down a little and I can see the bearing wobble very slightly in the housing.

Has anyone had these problems and how much play can I get away with? How much should the shaft end move up and down with the bearing retainer installed? I'm hoping the answer is a little.

Thanks.

Post by **wesk** » Sat Jan 02, 2010 10:30 am

That bearing will allow radial movement. The play measurement must be taken at the bearing's intersection with the shaft and not at the front tip of the shaft. The front of the shaft will be kept still in the pilot bushing in the flywheel.

53a1 · Post by **53a1** » Sat Jan 02, 2010 12:27 pm

Thanks Wes.

I read through manuals and it seems they are more concerned with the items you mention. They say to tap the bearing into the housing until the snap ring is seated. What's to prevent the bearing from spinning in the case if it's not a press fit?

53a1 · Post by **53a1** » Sun Jan 03, 2010 6:37 pm

Didn't get much activity on this one but from what I've read this seems to be common.

I'm thinking of using Loctite 638 Retaining Compound to bond slip fit parts. It fills in up to .015 gaps which is perfect. I can slide the bearing forward a little bit so I'm planning on cleaning with some carb cleaner to get the oil off then try this stuff out. At best it will prevent the bearing from rotating in the case and slow wearing on the case housing. I also ordered a new pilot bushing.

Post by **wesk** » Mon Jan 04, 2010 12:34 am

That front case fit was meant to be anslip fit. If I recall correctly the front shaft cover actually tightens against the that bearing's outer race so it should not be able to rotate.

53a1 · Post by **53a1** » Mon Jan 04, 2010 10:41 am

Good point Wes. I'll take a closer look at it.

Post by **wesk** » Mon Jan 04, 2010 10:56 am

The snap ring doesn't really hold the bearing in. It simply stops the bearing from going too far aft. Then when you install the front round cover it has a small step inside that pinches up tightly against the forward edge of the bearing's outer race and pushes it tightly against the snap ring which pushes tightly against the front side of the main case.

53a1 · Post by **53a1** » Mon Jan 04, 2010 3:21 pm

That's exactly what I was going to investigate and you took care of it. You are awesome Wes.

Before I button it up I need to put in a new gasket for the round bearing cover which is on order. The previous owner put RTV in there a luckily he use very little so it didn't enter the bearing and oil supply hole. On the flip side it wasn't sealing worth beans.

BTW, I know I should do more investigation on this tranny before I run it but I had a chance to run it under power through the gears before it was pulled out and it worked fine under no load. I'm going to drop the tranny and power plant in the rolling chassis and give her a run around the desert.

Post by **wesk** » Tue Jan 05, 2010 12:02 pm

The cover gets a very thin gasket. A thin piece of linen texture type writing paper traced and cut is all that is needed.