Both Rear wheels locked up while turning. Any ideas?

[NNespeca]

Figured you guys might get a laugh at a couple of these pics, some of these press setups have been real sketchy. Definitely a two man job, one guy to work the jack, another to hold and then catch the shaft assembly once the bearing pops off. One problem area, had to cut out the outer race on the inside of the input shaft, not enough room to get the jaws of the bearing puller in there, service manual does recommend a special tool for that go figure. Other than that it has gone smoothly. One piece of advice, make sure to order extra balls for the syncro assemblies. Those little things like to shoot across the garage while trying to reassemble. And make sure your press has plenty of clearance.



Anyways, I have 3 full days in on this project so far, hoping to get a 4th in this weekend. I've got all of the bearings replaced on the input, output, and countershaft. And the only bearing that looked/felt bad was the rear output tapered roller so I kind of feel like replacing every single bearing was overkill, oh well, piece of mind I suppose. Next steps: need to pull a couple outer races out of the housings, clean everything up, replace seals, and start reassembling. I imagine it will be a little tricky getting the endplay shimmed to spec. Oh, and gonna replace the rear main seal and clutch while everything is torn apart. Lots of fun...

 

[NIsaacs]

Looking good! Based on what I can see in the pic's and your observations, you might not have found the culprit that locked your axle.



Nick

 

[NNespeca]

My only theory at the moment is that the trashed rear bearing allowed enough endplay/chatter into the output shaft to allow the syncro to accidentally engage two gears at once, possibly 3rd and 4th. I seriously doubt the rear bearing alone could seize the entire driveshaft/axle.

 

[NIsaacs]

Yes, like you say, the bearing is bad but not that bad. Locking two gears is possible but not probable, especially 3rd and 4th, they are on the same fork and shift collar. The forks would prevent any two gears from engaging unless they were bad or there would need to be significant end play in the bearings on the main shaft. Again, the bearing in question did not look bad enough to cause all your head ache's.



Nick

 

[seafish]

NICE work, especially with all the press improvisations, so far... . and I DO hope that it cures your lock-up problem!!!

but NIsaacs might well be correct in saying that it MAY not... that bearing you noticed, while obviously running a hot at some point,at least in the pic you posted, does NOT really "look" damaged enough that it would allow enough play to let the transmission shafts bind up.

Did you check that particular bearing for radial and/or end play while it was still on the shaft??

 

[EricBu12]

Also the problem with that rear bearing is that it can be dry when running. . a lot of people overfill the transmission by about a quart or so. . When filling, go to the normal fill amount then tip the truck on the right a little to shove another quart or so in it. . this is what I did with my 2001 5600.

 

[NNespeca]

I started reassembling the transmission today, using a cherry picker I lowered the input/output and counter shafts into the bellhousing along with the shift forks. It was a little tricky getting everything lined up while slowly lowering making sure nothing was binding. Got that all done and then ran into a fairly major problem while getting ready to drop the main case over everything. In the main case I pulled the outer race of the "bad" rear output bearing. I then proceeded to press in the new outer race, there was no press, it slid right into the bore! I measured the two for comparison sake and the brand new 45220 Timken Outer Race was roughly . 016" undersized. The bad bearing actually enlarged the outer race of the bearing and also enlarged the bore ID in the casting! I've never seen that before. Pic below shows the larger bad bearing on the left and smaller new bearing on the right. Going to visit a local machine shop Monday to see if they can sleeve and rebore or shim or something tricky to get this bearing to fit properly. Looking online there is a "new" main case on eBay for $600, might be an option if the machining fix doesn't pan out. Anybody seen this before?

 

[Yo Hoot]

. 016" and the race isn't cracked? Wonder if it was an oversize bearing if such a thing exists for some previous botchup?

What does the new OD measure? I looks like it's supposed to be 4. 125"

 

[Nyoest]

Where did you get your bearing kit? I'd try to order another from an other source or obtain measurements to verify your new race is correct.

Is there any evidence of the race spinning in the housing? Color or metal transfer?

It could be a repair for an old bearing that spun in the housing.

 

[NNespeca]

The new 45220 cup OD measures 4. 125" which matches the specs on Timken's website. The "Bad" cup OD measures 4. 138" to ~ 4. 141". It doesn't appear to have spun in the housing. It does look like there was a lot of heat and wear on the tapered face. See pic below, its fairly obvious the old vs new.



I ordered the bearing kit from quad 4x4 in Montana. The bearings all seemed fine, there were a couple Timkens with "India" stamped on them instead of "USA" but other than that no complaints.



I will look around to see if Timken offers an oversized Outer Race.

 

[Yo Hoot]

That's interesting. I'm wondering if the heat took the hardness out of the race, allowing it to stretch.

They say the problem is not enough lube to that bearing... is there a mod that helps with that I'm wondering?