Undersized Input shaft (1 Viewer)

[65swb45]

I will add this to the list of 'just when you think you've seen it all...'

Just pulled a standard H42 off of an F engine that I am servicing at the shop. Customer complained of growling noise when the trans was in neutral. I told him that most likely was the input bearing of the trans, followed by pilot bearing. When I separated the trans from the motor, we saw what at first looked like a piece of the pilot bearing attached to the tip of the input shaft. But when I went to show him the interference fit of a pilot bearing to the trans, THE BEARING WAS SLOPPY!!!


Pulled out the micrometer. Yup. Undersized. All my 3speeds, all my 4speeds, even the. 5speeds, all .58" on the snout. His transmission:.50" snout. WTF?

 

[65swb45]

 

[OverLand Cruisers]

Weird! WTF is right.

 

[whitey45]

Looks like it got turned down by a bad pilot bearing? Was it a needle bearing pilot?

 

[ginmtb]

Sounds like a personal issue...

 

[pjohnson]

Looks like it got turned down by a bad pilot bearing? Was it a needle bearing pilot?

I agree. What's the measurement at the base of the snout?

 

[65swb45]

The thing is that the WHOLE shaft is that diameter. Carnage is not smooth like that. The bit at the end is a pressed on sleeve. It is the correct diameter for the pilot bearing.

 

[whitey45]

The worn part is the same width as a pilot bearing? I doubt that's a pressed on sleeve! Quick heat and should come right off?

 

[pjohnson]

Weird.

 

[4Cruisers]

Shouldn't it be pretty straightforward to find an appropriately sized bearing (width, ID, OD) from Timken, Koyo, etc.?

 

[reddingcruiser]

I'm sure Mark has the right one (at least one!) laying around.

 

[Rock40]

Merely a guess but I think .50" is the inner bore of a standard GM type pilot bushing. And that size is too precise for a bearing to have worn it out. Perhaps the shaft was machined at some point for a V8 swap and not it's back to Toyota?????

 

[65swb45]

Ross, all the GM conversions I've ever worked on have the same shaft diameter as the Toyota. My best guess, seconded by a local transmission rebuilder who has 30 years of experience and has also not seen this, is that the shaft was turned down to deal with a galling issue and sleeved, but that the sleeve has failed. But since he has not bothered to mic input shafts, he can't say for sure that there is no application for which it could have been turned down.

Since it was run that way, not properly supported, the only responsible course it to disassemble and check the tip of the output shaft to see if it was damaged. At that point, installing a correct input shaft is a no-brainer.

 

[RWBeringer4x4]

I thought I read something, somewhere, about an early GM conversion that required the input shaft to be machined. Perhaps one of the very early, pre-custom bellhousing conversions using a HM housing or something?

If Mark and Jim don't know about it, I'm probably making it up - but I remember being concerned about this before I took my Lakewood scattershield conversion apart.