Getrag blues
 

Good morning guys,
so one day coasting to a stop on a highway construction the transmission started doing a whining noise. After i took off from the stop i went through the gears and could hear the whining noise still. At highway speed in 5th gear i felt like a shudder or jerk from under the cab and went to the shoulder on the highway. I let off the throttle, and coasted alittle bit then got back on it and i lost 5th gear. The truck acted like if i was in neutral. I drove it home for about 10 more miles in 4th gear. I removed the transmission and upon disassembly found out the rear counter bearing was toast. This transmission was rebuild a year and a half ago and had less than 8k miles on the rebuild. When i took off the rear bearing retainer/ transfer case adapter, the bearing was completely destroyed. I did not see any shims on it, only on the output shaft. Im pretty sure this “reputable” shop got the preload wrong and caused this damage. The bearing also spun on the bearing retainer. Attached is a pic of the retainer. Is it reusable?
https://cimg2.ibsrv.net/gimg/www.die...0501b4480.jpeg
https://cimg4.ibsrv.net/gimg/www.die...5078d8df8.jpeg
https://cimg9.ibsrv.net/gimg/www.die...67ef27f78.jpeg
https://cimg1.ibsrv.net/gimg/www.die...7c3b93dac.jpeg

It's the lip on the edge of the pocket that matters. From the pic looks ok. There should be shims in there. At least you don't have an exit hole in the tailhousing. (I have a core like that.)

From what I have read, the bearing preload in the Get-Rag is critical. I got a rebuilt G360 from an outfit in San Antonio TX and the preload is loose. The trans rattles like the dickins in neutral. Otherwise it shifts and sounds OK when pulling or when the clutch is disengaged (pedal down). Put it in neutral and let the clutch out and it rattles louder than the engine and I have no muffler!

I read that having the preload to tight will toast the bearings. I figure I'll drive it for a while longer but now that I have a good garage here in Oklahoma I'll eventually get the time to tear into it myself and see if I can get it right.

Thanks for replying Edwin. Yea this “reputable” shop is in San Antonio also. They have rebuilt it 3 times already under warranty. This time it lasted alittle longer than the one year warranty and they wont warranty it. When they rebuilt it the first time it rattled like crazy also in neutral. This time it seemed nice and tight, no rattle at all but no shims on the counter shaft leads me to believe the preload was wrong.

U2 slow, thanks for your input. If you zoom in on the pic you can actually see where the shims rest, and it look worn from the spun bearing. Im not too sure though. If it is worn do you think a machine shop can clean it up and as far as the preload goes, can i make up for it with more shims per say?

If still has a good surface, then yes, as many shims as it takes to get the preload spec.

manual:
http://www.dieselhub.com/pdf/getrag-g360-manual.pdf

I would de-burr that pocket and reuse it. I have all of mine set up on the tight side of the specs. Taper bearings tend to wear a little and cause the set up to lose preload.

I finally got all the parts needed for this rebuild, and upon removing the counter shaft i saw that the cluster is alittle damaged at the rear where the rear counter shaft bearing got spun. Do you think i can run it like that or should i replace the whole cluster?

Thanks for all the input guys!

If you can knock any burrs off, and seat the bearings and clips properly... I would attempt to run it.

Just remember the getrag doesn't tolerate lugging well, and that 4th is your strongest gear because it doesn't run power through the countershaft.

When I rebuilt my NV4500 it took me weeks to get the pre-load right on the counter shaft and main shaft....this included time waiting for another shim package to show up.;) I had to make a back yard press to load the bearings, under my bench with a bottle jack, it's this "loading" of the bearings that make all the difference in getting the pre-load correct. And don't just say good enough if your off by .001 or so...I spent extra time to make sure I was dead center in the range that they allowed...I have over 100K miles on my rebuild so far with a ton of loaded highway miles and drive it everyday with no major issue.

Generally I would drop the bearing in there and then with a depth gauge I would drop that to the top of the bearing. This will give you a measurement of what you need to preload the bearing. You want it to be out about 6-8 thousand of an inch above the housing. Plasti gauges are nice if you want to get a better measurement.

That pocket looks good to me, if you did damage it a machine shop can do this easy! The method would be to cut the hole bigger and come in with a bronze seat with keyway that would take a race.

Hey guys, when the rear countershaft bearing spun on the case it made the diameter of the race bore bigger. Can i just weld more meat on that bore and have a machinist rebore it to spec of the race? Will it hold up? Right now as it sits the race will go in all the way by pushing it with my hand.

Ive just used Loctite 609 retaining compound or Permatex sleeve retainer when ive had those issues in the past. (It'll fix spinning races ect 100%) But It also depends on how bad it bored it out. Does it have room to wiggle around or enough to visably see a gap? (spinning is fine) Also im not certain but unless your input/output shaft(not counter shaft) bores are really bad i wouldnt put any on those races because I think theyre suposed to be able to move slightly from the preload to help lock it in place. (not 100%)

Once the race is in its bore, theres a little bit of wiggle to it.

Also guys, the countershaft was kind of hard to press out of the cluster gear. I dont know if heat was a factor that contributed to that. I saw the master tech video on youtube on the getrag rebuild and saw that it came out fairly easily. Will i damage the new countershaft if it is just as difficult pressing it?