Transfer Case Jumping out of High

[m139h2otruck]

I have run a search on this topic, but still don't have a very good picture of the solution, except for a full replacement of the transfer case. Could it be as simple as an adjustment in the linkage? Are there detent balls/springs on the shifter rods? Bad/dirty oil causing who knows what for problems? Anyone have this problem but was able to solve it without changing the whole box? Thanks

 

[acetomatoco]

Usually just adjustment of th linkage...get the manual breakdown and see how the rods move in and out..and the detents..disconnect linkage and see if the rod is in the detent or jumps in when you disconnect... I have a 5 ton that when going into low, the lever hits the floor if you try to do it slow and the shifter stays in neutral... If I really slam it, it will engage low...thru inertia... Onadesedays I am gonna fix it.. but in the meantime I just slam it.... ACE

 

[SasquatchSanta]

I experienced this same problem with an M37 transfer case several years ago. After rebuilding the case it wouldn't stay in high gear without applying forward pressure on the shifting lever.

I pulled it back out, carefully inspected it --- couldn't find anything wrong, and ended up rebuilding another case. The rebuilt case is still in my garage --- tucked under the bench.

I'm told if you constantly apply pressure to keep a transfer case in gear is't only a metter of time before the problem will get worse .

I'd also like to know what causes this problem.

 

[m139h2otruck]

Since getting the truck and trying the gears around the yard, the transfer still will not stay in Hi unless you hold it. Found a hole drilled through the handle and a rope with a hook in the cab, and guessed that the drivers were hooking the rope up and holding it in hi to drive! disconnected the shift rods and readjusted so the handle just hits the floor in low and still it will not stay in hi. Shifter feels like the detent ball is not engaging the grooves in the shifter shaft. Even took the spring and ball out and sprayed WD40 (heavy) in the hole. STILL no luck. Drained oil and changed to GL-5 (Sams Club) and the oil, while black, did not have any big chunks or much metal at all (less than transmission).

Any other suggestions?? I think the transfer is original, even though the engine has a 1989 rebuild plate on it.

 

[jwaller]

mine was jumping out of high and I had to replace my xcase.

 

[m139h2otruck]

jwaller: Did you ever determine why the shifter was jumping out of gear?

 

[jwaller]

it was some problem in the case itself. I used a ratchet strap to hold it in H for a few months and then it started doing it in L as well and I finally replaced the whole unit and the problem went away. I did find a large chunk of metal that dropped when I changed the fluid.

 

[JDToumanian]

The TMs state that popping out of gear is due to worn gears or bearings. This is assuming, of course, no other obvious cause like linkage adjustment or broken / missing detent ball, plunger or spring. It's cheaper to swap out the defective transfer case for a good used one than it is to rebuild the one you have.

Jon

 

[devilman96]

Often times this starts with poor maintenance pratices where shift linkage is concerned . To much slop allowing the shifter lever to bounce while driving causes wear on the detent and eventually it moves on to the forks themselves.

Using a bungie or rope to hold it in is certain death to a TC. If the problem is corrected fast enough by replacing the detent this can be avoided.

Keeping the linkage with proper tension and adjustment along with frequent fluid changes will help keep you out of this mess all together.

 

[supermechanic]

Just bite the bullet and get a new case.
I played with a case that had the same problems as yours for more than three years,
all I got was experience climbing in and out from under the truck.
Just before the case came out, it wouldn't even drive in reverse in high range, had to shift to low to go backwards.
I got a good deal from Ken Kublo in Pa.(570) 663-2805.
I still have the old case, someday I may get around to opening it up to find what the problem was.
P.M. me if you want some ideas on the best way to replace the unit.

 

[saquishmike]

What is a used t-case going for?

 

[supermechanic]

I paid 750.
both eastern and memphis want much more.
if kublo has one he will stand behind it, when i got mine, they said if it proves that the replacement is bad, they will take one from a running truck that is known good.

 

[5ton beachbuggy]

I had a 5 ton transfer case that started jumping out of highrange. I found a broken snapring on the back of the input shaft. take the cover off the back and check it. I put a new snapring on and fix the problem.

 

[MilitaryRestoration]

ahh this sounds soo familiar :-/ unfortunately the best thing to do is replace it and when you do so make sure, if using a helper, they hook up the air shift lines correctly or else you'll have even more head aches like I had to go through...

like someone said above when the lever isn't adjusted correctly is rides on the little detent eventually just wearing it out... and this is what holds it in. We ratcheted the crap out of ours to the back of the cab and it last maybe...another 50 miles until high range went completely out, so then tried adjusting it even more and ratcheting that to the cab again and ... nothing. So luckily low still worked for us and we legged it back home. Like I said though, save yourself some trouble/time and just get a new xfer case and then rebuild your old one and keep as a spare. Only time till the new one does the same or who knows what else can go wrong. I did a write up about my problems, should be able to find in in 5ton area. If you have any other questions dont hesitate to ask me. I know what you are going through and what you are about to be going through :-/

ps dont forget about the air lines lol... can't preach enough. Caused me head ache after head ache, not to mention lost money with truck sitting for months

 

[saquishmike]

Thanks for the great advice guys . Will try easy stuff 1st and hope for the best.

 

[98hd]

I replaced mine also, due to popping out of high. I paid 400 for mine, but it came with no guarantee that it would be good. Got lucky and it was though.

 

[BEASTMASTER]

hey mike, chuckrans junkyard in bridgewater had a 5 ton up there a few weeks ago. used to belong to town of halifx for snowplowing. had a nice cummings in it to.

 

[saquishmike]

Thanks Beastmaster I will give them a call. And does anyone know if the drive train in the 50 series is the same as the 800?

 

[jatonka]

The transfer cases are the same in the 5 tons. Gasser, Multifuel, Cummins. But not the 900 series of 5 ton, totally different. JT

 

[MilitaryRestoration]

jatonka is completely right... however the drive lines are different when comparing from multi fuel to cummins... My donor truck was a 50 series and so just swapped drivelines and she works...