Transfer Case Problem with Low

[jamawieb]

I have a 1968 M35A2C with the air shift transfer case and can not get it to go into low gear. High and neutral shift fine but when I try to shift into low, it feels like somthing is blocking it. I tried rolling the truck in high and shifting the transfer case into low but it still would not move, I then took off the cover and the top vent cover off the transfer case but couldn't see anything wrong. Looking into the case from the top, everything looked really good, I looked through the TM but couldn't really tell anything from the diagrams. Has anyone else had this problem and found a solution? I've also adjusted the linkage but still could not get it into low gear.

 

[jamawieb]

Ok, so I guess no one else has had this problem. LOL! Does anyone have pictures of the transfer case internals that might give me some idea of what could be blocking it from going into low gear? The TM's do not give a clear picture of the inside. Thanks

 

[212sparky]

How about a picture of you're tc internals

 

[jamawieb]

It's still in the truck and can only take off the vent plate on the top and all I can see is the top of the shift fork. I'm trying to figure out if it's something that can be fixed easily with the transfer case in the truck. I'm really hoping that someone has experienced this and can lead me in the right direction. If not, i'll just have to replace it.

 

[212sparky]

It sounds like your synchro on the low gears are worn out or the shift fork is damaged

 

[randygk]

This drawing does not show the shifting fork or synchronizer assy which is on the center of the input (red) shaft.
The synchronizer moves forward (low range) or aft (high range) to engage a gear and drive the counter (center) shaft.
You could have worn synchronizer, bad bearings on low range gear causing misalignment,
or shifter fork problem

 

[m-35tom]

try shifting it with the truck going 10mph and see what happens.

 

[poppop]

When mine would not find low range it was a bearing gone bad on the shaft that the shifter operates on. When it went bad a piece of bearing got into the synco and busted it. When it tried to shift to low there were pieces missing on the shaft which did not allow for enough movement to get into low. I drove it a couple years at the Ga Rally with no low range but then it started making more and more noise so pulled it and opened it up and that is what I found.

 

[jamawieb]

Awesome guys, thank you. I'm going to drain the oil and see if anything is in it. I've tried driving it and shifting into low but it didn't work, same results.

 

[73m819]

Be carefull about driving and "forcing" into low, my 819 would not go into low, after I replaced the transfer, I FORCED it into low, locked things, had to use a bar to get it out of low, if it had been in the truck would have locked the truck up and not going anyware.

 

[jamawieb]

Update: I took the plug out and found bearings. I'm in the process of taking the transfer case out and wondering if anyone has a good source for internal parts. I have a feeling that the synchro is shot.

 

[michigandon]

Just started having the same problem with my truck.

 

[jamawieb]

Sorry to hear that, if you drain the fluid and find metal or ball bearings on the magnetic drain plug, you'll know for sure what the problem is. I just finished rebuilding mine and found that one of the bearings on the low gear synchro went bad. There a 4 bearings on the synchro and it seems everyones problem comes from the low gear bearing going bad. The case is really easy to work on but the bearings are expensive. I could have bought a used case for the same amount as I spent on the bearings for the input shaft but since everything inside the case looked near perfect, I went ahead and rebuilt it to be sure I wouldn't have any problems in the future.

 

[michigandon]

Looks like I've secured a take out from an ad on this site. I'll hang onto the old one and rebuild it at my leisure to keep as a "spare" (not unlike my old airpack and master cylinder).

Don't suppose you know the TM section to R&R the t-case?

 

[gringeltaube]

.....you know the TM section to R&R the t-case?

TM9-2520-246-34, section III and TM9-2520-246-34P

G.

 

[michigandon]

if you drain the fluid and find metal or ball bearings on the magnetic drain plug, you'll know for sure what the problem is.

Mine's full of shrapnel as well.

 

[m-35tom]

i can't imagine the bearings being expensive if they are ball, what is the number, i'll check my supplier. they usually are much lower than anyone else.

 

[gringeltaube]

Tom, the gears take two high load (15-ball)bearings each (BL210Z) and those usually cost at least twice as much as the normal deep groove ball bearings, same size. (I know that you know this... )

See my post with the "civilian" numbers for all 6 input shaft bearings, here....


G.

 

[m-35tom]

i would think that perhaps the failure of these brngs is condensation related since they are at the top??

 

[jamawieb]

i can't imagine the bearings being expensive if they are ball, what is the number, i'll check my supplier. they usually are much lower than anyone else.

I checked several different vendors, my father in law rebuilds tractors and had a supplier that he buys all his bearings from but all where very high. The input shaft bearings were the most expensive, the rest were some what reasonable.