Mr. Plaine

Alright a little bit of a long story.

The origonal getrag in my truck lasted me 70k and the previous owner who knows how many miles, but the tranny did well. Since then i have re built it twice. Both times using all new bearings from an ebay vendor. Bothe times the pocket bearing between the input and the main shaft pitted the input shaft so i replaced the input both times.
The second tranny lasted me a year,20k miles. I shimmed it to the recomended .006 or .008 whatever and it worked great for the 20k then just took a crap on me.
The Second rebuild (third tranny) i did the same but shimmed it a little looser somewhere like .004. And i replaced all of the sycro's bearings and input shaft again. This has only lasted me 10K if that.
I am now a bit . As far as i can tell this time the only bearing showing major wear is the pocket bearing. Both times i rebuilt the tranny the shim stacks for the main and counter shaft have been different amounts, but they both had the same end tollerance, could this be an issue?
I am going to try and have the parts guy cross the bearings over and get all Timken, because i am not trusing these cheeper Jap bearings. I have never checked the shift forks for wear, just bolted the top plate back on. Could this be an issue?
The biggest trailer i tow is 6K. I do a lot of around town driving and my pump is turned up but nothing serious in terms of power. Any other suggestions.
Thanks

Ian

bgilbert

What lube are you using, although not 'that' important, but most important, are you overfilling the trans by 1 to 1.5 quarts?

Mr. Plaine

Mobile1 5-30 synthetic. 1 quart overfilled through the shifter. 5 quarts total i believe.

Ian-

rockfoot

You mentioned....
"shim stacks for the main and counter shaft have been different amounts, but they both had the same end tollerance, could this be an issue? "
Not sure if you meant to say "tolerance"... There should be no tolerance..... Those Timkins (cone shaped) bearings , japanese or not have to be preloaded... I went through all this about a year ago...

12valve@heart

I'm looking at your original post and I don't see where you say what part failed each time aside from the pocket bearing pitting the input shaft. Was it the pocket bearing that failed or was it another failure that caused you to tear into the tranny? Since you're talking about bearing quality, I'd assume bearing failure but which one?

Not knowing your driving style, one of the questions to consider is whether you tend to lug the motor. With the torque that the Cummins can produce, it can tear up a tranny if lugged.

Assuming that you preloaded both shafts to .004-.008, that sounds correct. Let us know a bit more about the rest of the damage and we'll try to help you diagnose it.

Haraga

Does anyone have the tapered bearing part numbers for the Getrag 360 input and output shafts? Also seal #'s of possible. Thanks in advance.

bgilbert

Why only replace them and not the two on the countershaft? I've priced them locally and it comes out to the same as the kit you can get from www.zbag.com. In this kit you also get gaskets and the front plug. Don't forget shims from zbag.com as well.

Haraga

I have the other parts and I just need the timken #'s because I am in town now and I will pick up the parts and take them to the truck 50 miles away. It will save me the trouble of a parts run. Thanks for the reply.