Hi, I'm new to working on military transfer cases and need your help.
I have a used T136-27 air shift transfer case.
the pinion nut and washer are missing from the input shaft.
when spinning the input shaft it walks front to back and makes noise.
I will be starting a tear down tomorrow to see if I have bearing damage or gear damage. my first question, does the pinion nut preload the bearings on the input and control the walking motion I am seeing? (kind of like the pinion in a automotive differential) or am I going to be surprised tomorrow and find a junk gear.
If somebody can point me in the right direction to purchase a maintenance or overhaul manual for this transfer case I would appreciate it.
Thanks
The manual is TM9 2520-246-34 or TM9 8623. The nut on the shaft holds the bearings tight on the shaft. If it is missing, the shaft will do like you said. If this transfer looks to be messed up, you are better off buying a known good one from a SS member parting out a truck. By the time you buy a bunch a bearings and gears, you will equal the price of a good unit. I just got finished with a Timken T-77, it took weeks of part-time fiddling to get it rebuilt.
Thanks, I'll look for the manuals I understand what you said about the cost if the transfer case needs a lot of work. the front bearing is $160.00
I'm hoping the inside look decent (of course that would not be my luck ha ha).
If I need to replace the front bearing along with the missing nut and washer and related gaskets I'm already looking at $200.00
Front bearing missing???? Do you really mean the bearing or just the retainer which also holds the seal? Also, you didn't mention if the companion flange is also missing or not. ??
FYI: All 6 bearings on the input shaft are ball brg. type, so there is nothing to preload. As NDT said, the complete shaft assy with gears and syncro is held in place by exactly that (your missing) nut which presses the washer, companion flange and front bearing together. Without it the shaft can slide in and the syncro starting to engage (if it was in neutral) and also the gear on the opposite side can eventually touch the housing. See drawing.
For peace of mind you can pull the drain plug and see what the magnet had collected.
The companion flange (the attachment flange for the driveshaft ) is there.
The retainer is still there (if we are talking about the cover plate bolted to the main cover).
What I do know is missing is the washer, nut and cotter pin on the front side of the input shaft.
you brought an interesting point to light, I was under the impression that the bearings were tapered rollers that required pre-loading to reduce the shaft end play. Now that I know they are ball bearings I question why a ball bearing would cost me $160.00 (unless that price is a kit price and includes all the bearings on the input shaft)
Thank you for the cut away diagram. if anybody has a link to an exploded view of this transfer case I would be very grateful.
Thank you for jumping in so quickly with the advice and questions, this will really help me on the project.
I thought some pics would be better than the exploded diagram in that manual...
So if your TC doesn’t look like pic#1 because the outer bearing is missing you might also need the spacer that goes between brg. and comp. flange.
The next pic shows the 3 bearings and 3 spacers installed in place.
In the last one you can see all the parts involved, in the correct sequence.
As for the bearings, the large one is a common 6310 NR (= grooved W/ retainer ring) which sure cost less than that.
Just in case, the two smaller ones inside the gear are high capacity type (15 balls), one side shielded. In the NTN catalog you find it as a #BL210 Z (90x50x20). Those usually cost 2 -3 times as much as the std. ones, so that would possibly explain the $160.-
Awesome pictures thanks! by the looks of things I am only missing the front nut and washer.
I have a manual on the way. I wanted to start the disassembly yesterday but life got in the way.
I'm taking the T.C. to my shop tomorrow and hopefully I'll start taking it apart, I'm right in the middle of re-flooring a boat, the wood should be delivered in the morning, I'm hoping to turn my son loose on that job so I can dive into the transfer case. Then I need to design a support cradle in order to mount the T.C. in our truck. (that is if the T.C. is worth repairing).
I'll keep you posted on how it goes, I have a feeling I'm about to learn a bunch about T.C's
Well I have the transfer case completely disassembled, the good news is I only have a few minor problems (two bearings on the input shaft need to be replaced). I found the shaft end play was caused by the rear retainer clip was broken and laying in the cover plate. the good news is the shaft (or gears) did not hit the inside of the case so there is no internal damage. the best price I have found on the BCA 1210S bearings is $110.00 each. as it stands right now I think the repairs can be done for a grand total of $250.00, so I'm pretty happy about that.
__________________
"IF WE EVER FORGET THAT WE'RE ONE NATION UNDER GOD,
THEN WE WILL BE ONE NATION GONE UNDER."
Ronald Regan
$110 ea just for those bearings? Man that hurts!
Another reason not to scrap the old sprag T-cases: that pair of brgs. inside the smaller gear (low range) usually lasts forever.
I'm curious now to know what the equivalent Japs. NTN would cost me here.
G.
Update: FYR, BL 210 Z (NTN Japan), my cost = U$S 35, tax incl.!
Last edited by gringeltaube; 02-10-2009 at 11:15.
Reason: Update....
Better news I was able to track down the bearings through a company in New York,
the high load shaft bearings that were $110 ea are now $33.50 and the two case bearings have come down from $230.00 to $95.00.
I did not have to compromise on the brands I can still use BCA, SKF, and FAG.
I should have the gaskets and bearings in about a week. in the mean time I'll get the case cleaned and powder coated and have it ready to assemble when the bearings arrive.
__________________
"IF WE EVER FORGET THAT WE'RE ONE NATION UNDER GOD,
THEN WE WILL BE ONE NATION GONE UNDER."
Ronald Regan
136-27 transfer case
