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Transmission Input Shaft Noise


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Hello All,

My transmission has been making some noise for a while. Searching this forum I determined it to be the input shaft bearings are done. The noise comes from the trans when the clutch is out regardless of what gear or in neutral. The noise is a bearing chatter sound that used to go away once the trans warmed up. Not any more.....

My questions are:

Is there any way to test a transmission before it's installed into my car? I've got a replacement trans out of a 73 in my garage but don't know the condition of it.

What should I do to this tranny before I install it?

Thanks in advance.

Patman in Tehachapi

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Guest Anonymous

Regarding testing transmissions, you can test the input bearing for excessive wear. In your case, constant bearing sounds in every gear when clutch engaged, it could be the 'counter shaft' or 'layshaft.' Those are the most popular places for bearing failure. And fortunately, the most rebuildable for a shop with the proper tools since they can be replaced by removeing the input side housing.

You can determine if there is excessive play on the input shaft by wiggling it with your hand. It is meant to have some play in it but more than 1mm in each direction measured at the end of the shaft is excessive. The input shaft has a bit of latitude built into it because the clutch friction disk can put a side load on the shaft. Besides, the pilot bearing keeps the shaft and disk centered.

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Is that play at the end of the input shaft "up/down" or "in/out"?????? I assume up/down but please confirm.

Any idea of what the cost would be to fix my original tranny if it is the layshaft bearings? Just round numbers would help. What else should I have them do at the same time while they have it apart?


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Guest Anonymous

If I remember there was no 'in/out' play (or extremely little) and most of it was sides and up/down. "The Pickle" is a Tii ... I think they put 242 Getrag as the standard trans but I don't know. Price wise, yu have to shop around. Its difficult to find a shop that takes your and fixes it. They typically take your transmission and return a completely rebuilt one for the large price of $2500. I nearly bought a 'rebuilt' 242 for 1500 but when I looked at it I wasn't impressed. Went and bought one at a salvage yard for $300 and have been tweeking it ever since. Still not noisy. If you are a diehard DIY you can do it yourself but it is tricky because everything needs to be properly shimmed. R & R of the bearings is doable "they say" but shimming it perfectly requires some practice.

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Actually, the input and countershaft both spin in neutral,

and the countershaft bearings are all sorts of wimpy

compared to the input bearing, so they usually go

first. Not that that matters much....

For bench testing, I've had some luck spinning the transmission with

an electric drill and just listening and feeling while shifting. It's not guaranteed,

but I've had good luck.

Also, look carefully at the input and output pilots- the get chewed

up a lot after 40 years.



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