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Should I replace this input shaft?

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Old Sep 13, 2011 | 12:00 AM
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Question Should I replace this input shaft?

This is the tip of the input shaft on my trans that I am rebuilding.

The tip is somewhat scored, is it still good or should it be replaced?

Circled in blue is the original machined surface, so it doesn't appear to be so badly scored to the point where the diameter is smaller.



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Old Sep 13, 2011 | 12:45 AM
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That one has been run with a failed roller pilot bearing and then run again.

Getting it retipped would be a way to go rather than full replacement.

A bronze pilot bushing makes a lot of sense no matter how you go with it.
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Old Sep 13, 2011 | 09:29 AM
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Where can I get a bronze pilot bearing?
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Old Sep 13, 2011 | 12:12 PM
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Bushing. Not bearing.

Any general auto parts store should carry them.

The roller bearing that started being used OEM in the 90s has too high a failure rate.
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Old Sep 13, 2011 | 04:37 PM
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Originally Posted by jmd
The roller bearing that started being used OEM in the 90s has too high a failure rate.
pilot bushing/bearing wear typically is a result of a bent main shaft or bad main shaft bearing....which in turn wears/takes out the pilot.

the pilot bearing with a good transmission is basically a neutral rolling surface but when the main shaft starts to wobble...it will quickly kill it and then the FU bearing will eat into the main shaft

pilot bushings are typically bronze and a softer metal than a bearing type.

point would be to address why there is wear on a pilot bushing/bearing
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Old Sep 13, 2011 | 06:57 PM
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If the input is wobbling, it's because the bearing already failed.

A unit disassembled only from the engine can have normal wobble in the input since the pilot bushing / bearing is an integral part of the input shaft assembly. It's not a neutral rolling service. Nor is lateral play at the pilot end of the input a valid measure of anything.

I put bronze in; if the customer insists on roller on a long style (93-06) input, I pay close attention to the depth it's installed into the crank.
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Old Sep 14, 2011 | 08:33 AM
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Retip or replace. I would go back with a bearing though. Bushings are softer and will need to be replaced more frequently especially in higher torque or heavier vehicle applications where more force is applied to the bearing/bushing surface.
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Old Sep 15, 2011 | 08:28 PM
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What intervals (miles) do you recommend that pilot bearing be replaced?

Also what type of material should be used for the sleeve if it get retipped?
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Old Sep 15, 2011 | 08:50 PM
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Originally Posted by Hans Grüber
What intervals (miles) do you recommend that pilot bearing be replaced?
Anytime the clutch is replaced for absolute sure. If you drive through a lot of water whether its standing from puddles on the street or whatever tends to wash the grease out of the bearing as well. I typically take a small dab of high temp grease and smear it into the bearing upon installation and anytime the trans is removed from the bellhousing. There is no real milage # to say as it will vary depending on conditions. I can tell you this, it will last longer than any bronze type bushing you will find on the market.
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