Worn Transmission Input Shaft Pilot Bearing Surface (2 Viewers)

[ryanwk628]

I’m digging into a 4 speed transmission that I got from a part out and the input shaft pilot bearing surface seems to be worn 0.010 undersize creating a ridge where it looks like the old bearing would ride. I’m assuming the bearing froze up and the shaft spun inside the inner race. It also has a red color on it so I’m wondering if someone tried a bearing retaining compound on it in the past.

I was hoping to just reseal and run it, but I’m feeling more and more like I need to take it apart. What are my options? Do I need a new/used input shaft? Bearing retaining compound? Hard chrome it back up then grind to spec? Run a bushing turned to size instead? I am open to opinions. Thanks!

 

[charliemeyer007]

Yep, looks bad to me. I would rip the whole gear box apart for inspecting and cleaning - fix what ever is wrong: bearing, seals, shafts, gears.... Should then be good for many years.

Isn't that bearing in the flywheel actually a bushing - maybe they ran for a long time with loose bolts.

If the rest of the gear box is in good shape - you could carefully make that shaft undersized and make a new pilot bushing with an undersized hole to fit.

 

[Green Bean]

I don't know if it would be advisable or not but perhaps a speedi sleeve? Builds - The "Red Rocket" Troopy - https://forum.ih8mud.com/threads/the-red-rocket-troopy.1205247/page-66#post-15082353

Speedi sleeve help needed (Found Solution)

Putting speedi sleeve on parking brake hub. Used the install tool provided after putting jb weld on shaft. Bottomed out the install tool and sleeve still needs to go approximately 1/4 inch. So I got the sleeve off of hub, cleaned the hub back up and ordered a new sleeve. What have y’all used...

forum.ih8mud.com

 

[Living in the Past]

Isn't that bearing in the flywheel actually a bushing - maybe they ran for a long time with loose bolts.

Pilot bearing is a ball bearing. Not uncommon for them to come apart when pulling a transmission. Can see the end of pilot bearing on end of one of my spare four speeds.

 

[Mark Jennings]

The pilot bearing is a small roller bearing and goes in the flywheel end of the crankshaft. You should at least replace the pilot. Personally I would replace the transmission input shaft. I doubt you could find a speedy sleeve that small and it probably wouldn’t last. If your not to sure about disassembly/reassembly of your 4 speed, most transmission shops could help your out or maybe a used transmission from Mud classifieds.

 

[Mark Jennings]

Pilot bearing is a ball bearing. Not uncommon for them to come apart when pulling a transmission. Can see the end of pilot bearing on end of one of my spare four speeds.
View attachment 3587435

Gosh dang @livin in the past, that there be one heck of a transmission spare pats bin!

 

[Living in the Past]

The pilot bearing is a small roller bearing and goes in the flywheel end of the crankshaft. You should at least replace the pilot. Personally I would replace the transmission input shaft. I doubt you could find a speedy sleeve that small and it probably wouldn’t last. If your not to sure about disassembly/reassembly of your 4 speed, most transmission shops could help your out or maybe a used transmission from Mud classifieds.

Problem with a speedy sleeve those are designed to use with a seal would have to machine the shaft and install a sleeve that fit perfectly in the bearing. Pull the transmission apart to machine the end of the input shaft would just replace it.

 

[ryanwk628]

The pilot bearing is a small roller bearing and goes in the flywheel end of the crankshaft. You should at least replace the pilot. Personally I would replace the transmission input shaft. I doubt you could find a speedy sleeve that small and it probably wouldn’t last. If your not to sure about disassembly/reassembly of your 4 speed, most transmission shops could help your out or maybe a used transmission from Mud classifieds.

Yup, 15mm ID sealed bearing. This one must have locked up and the shaft spun in it. I didn’t realize it was bad when I bought it, only noticed it now going through and inspecting it. Doing research I’ve seen others use a bushing for just that reason, let the bushing wear rather than the trans. Advance Adapters uses bushings in a lot of their kits mixing odd trans and engine combos, so my thought was perhaps one could be made to match…

I guess I’m on the hunt for a trans or shaft, but thats what I was hoping to avoid.

 

[ryanwk628]

I don't know if it would be advisable or not but perhaps a speedi sleeve? Builds - The "Red Rocket" Troopy - https://forum.ih8mud.com/threads/the-red-rocket-troopy.1205247/page-66#post-15082353

Speedi sleeve help needed (Found Solution)

Putting speedi sleeve on parking brake hub. Used the install tool provided after putting jb weld on shaft. Bottomed out the install tool and sleeve still needs to go approximately 1/4 inch. So I got the sleeve off of hub, cleaned the hub back up and ordered a new sleeve. What have y’all used...

forum.ih8mud.com

I was thinking something like that, maybe turning it down and shrinking on a sleeve, or perhaps I could get it plated up 0.005 per side.

Loctite makes bearing retaining compounds that would handle 0.005 per side, but I’ll hate myself if I ever need to get it out in the future

 

[mattressking]

Run a wider bearing and you'll be good.

Use Nachi 5202Z, it'll grab the rest of the input shaft, easy fix. Pics courtesy @OSS

 

[ryanwk628]

Run a wider bearing and you'll be good.

Use Nachi 5202Z, it'll grab the rest of the input shaft, easy fix. Pics courtesy @OSS

View attachment 3587724
View attachment 3587729

Mud to the rescue! Thank you!