Need some help troubleshooting this issue. I recently changed the clutch in my 91.5 W350 4x4 5 speed, as well as the rear main seal, getrag input and output shaft seals. It was a new clutch flywheel set from rock auto which I pressed a needle bearing style pilot bearing into the new flywheel. Once I put everything back together I went for a very short drive. 1st gear felt good, 2nd fine, 3rd I started to feel a rattling. When I started to go down a hill and the engine started to hold back the truck it got violent. Pushing in the clutch didn't help. I pulled over and even decelerating in in 3rd, 2nd, or first still rattled hard. When you are accelerating the sound goes away and its smooth.

I assumed I may have maybe pinched one of the shims putting the back plate on when I put in the new output seal on. I pulled the transfer case and back plate off to check at it was fine, all the shims were in the right spots for the output and counter shaft bearings. RTV'd the plate and put it back on, and went for another drive to confirm and same issue. The only other thing I did to the transmission was install a new input shaft seal and remove and install the gear shifter. I don't recall seeing any shims on the input shaft retainer when I did that seal Would that make sense with the issues I am having? I didn't check the diameter of the input shaft where it goes into the pilot bearing could it be something to do with the pilot bearing? The original one was just a bushing. I really am having a hard time coming to terms that I will likely have to remove the transmission again.

 

Could be just low quality parts.
I wouldn't use anything other than a southbend kit and they aren't even expensive.

 

I am pulling the trans today, should have a better idea this afternoon. I am thinking my input shaft at the pilot bearing section is worn. I was in a hurry to get the truck back together and didn't measure it. The original bronze bushing fell apart on removal so it may have worn the shaft out of spec. Its a stock truck and I have no desire to turn up the power so I thought a standard replacement clutch would do, maybe I was wrong.

 

The stock style 13" clutch is decent. I didn't kill my first one despite having turned up the power. I changed it just because I had a lot of hard miles on it, and I was swapping the trans anyway.

I'm curious about the pilot bearing. The only needle style I could find for it needed the flywheel bored out. I went with the bushing again. Also needs to be greased up. If you didn't change the input bearing (very common to change), you may have destroyed the pilot bearing quickly.

Getrag gets shimmed from the stern - both the upper and lower shafts.

 

I just pulled the tranny and the the input shaft doesn't seem to have any play, I pulled the retainer to check if anything was off and reinstalled. Everything seems fine with the transmission, I pulled the back off when I did the output shaft seal and all the shims were back were they belong, checked twice. The input shaft tip where it goes into the pilot bearing measured at 0.75" except in one spot where I measured 0.74". The transmission was fine before the clutch change so I am leaning towards a problem with the pilot bearing or replacement flywheel/clutch. My stock 13" one started slipping, its a truck I don't use very often so just bought a standard replacement, its a farm truck. ( https://www.rockauto.com/en/moreinfo...93&jsn=1&jsn=1 ) This is the clutch I bought to replace the original 13", rock auto says its a fit but I am wondering if it is not right. It came with a flywheel, pilot bearing (needle bearing), clutch plate, pressure plate, and throwout bearing.

I will pull the bell-housing tomorrow and check the clutch and the pilot bearing. I am wondering if I did something stupid like install the friction plate backwards, if that is possible.

 

Pulled the bellhousing this morning and the pilot looks good, measured it and is correct for the shaft diameter. I am at a loss here. Would a bushing like the original help this? Is it possible that when I pulled the front and rear retainers to change the seals I knocked something loose?

I see I posted this in the wrong section, it should be in the first gen section. Could a mod move this to the correct section? I might get a few more suggestions in the correct section.

 

Reading again... not likely the pilot bearing. That interface would only be 'worked' when the clutch is released. It can't make noise when in gear and driving. The input and bearing are rotating in unison with the flywheel.

Does the gear shifter 'move' when you're on/off the throttle? Was the c-clip on the end of the countershaft when you had the ext housing off?

 

I don't remember seeing the shifter move but I usually keep my hand on the shifter until I reach 5th gear so I feel like I would have noticed if if moved. The transmission was fine before the clutch change. The only thing I did to the transmission was pull the shifter, remove the input shaft collar to change the input shaft seal, and removed the trans adapter to change the output shaft seal. I did slide the races out and checked for pitting but aside from that I didn't dig into it. All c clips still in place.

Has anyone had success with the needle bearings for a pilot bearing? I am not sure if I want to get the new flywheel machined for a roller bearing while its out. I am not sure what happened but I think you are right that its not the pilot bearing. I will likely have to dig into the transmission and see what is going on.... I have pulled the trans 3 times now and I am not putting anything back on until I know what the problem was and have it fixed.

 

Sometimes disturbing well-used equipment can upset things.

I bought a core trans and a rebuild kit before I dared to dig into mine any further than a top-cover swap.

 

Where did you get your rebuild kit from? I am also from BC.

 

Rockauto.

 

Would you happen to have a part number? All I see is kits with ball bearings, did your kit have ball bearing or tapered roller bearings like the stock bearings?

 

US Standard Gear ZMBK261WS... has tapered bearings.

 

Strange, that number doesn't show up for 4x4, shows up for 2wd. Is your truck a 2wd? I would think all the internals are the same. I pulled the input and main shaft out and I don't see anything that looks bad. Some slight pitting on the internal race inside the input shaft but nothing too bad. I don't see how it could cause the problem I was having. Thanks for the part number, I will likely order and rebuild since it's already apart. Will probably order a new input shaft since they are under $100 on rock auto.

 

Yes 2wd. I think the kit had rear seals for both. I will have to check again once home from work.

Bearing endplay or the countershaft walking (missing or broken clips) can make a bunch of noise.

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