HMMWV WONT STAY IN LOW GEAR

I have a 1989 HMMWV 6.5 non turbo with a 700R transmission installed. Transfer case (H) and (HL) work fine. When I shift transfer case into (L) I have to physically hold shifter in low position or it immediately jumps out of (L) position. The 700R transmission was already installed when I purchased the vehicle. Does this have something to do with the transmission or is there something else going on? When I hold in low gear it works fine. This did not just start. It has been doing this since I purchased the vehicle back in July.

The L versus H or HL is part of the transfer case. Could be several things, but the easiest (and most hoped for) is that the linkage is misaligned. Get under there and inspect the t-case linkage and get some pictures of the shifter as well. Since it has a 700R it has had shift linkage modifications or at least a new shifter to accommodate the 4 speed, 1989 it would have almost certainly left the factory as a 3spd.
Take some pictures, post them, folks here will help you sort it out.
Bulldogger

Bulldogger said:

The L versus H or HL is part of the transfer case. Could be several things, but the easiest (and most hoped for) is that the linkage is misaligned. Get under there and inspect the t-case linkage and get some pictures of the shifter as well. Since it has a 700R it has had shift linkage modifications or at least a new shifter to accommodate the 4 speed, 1989 it would have almost certainly left the factory as a 3spd.
Take some pictures, post them, folks here will help you sort it out.
Bulldogger

Click to expand...

Thank you very much. I will check out the linkage as suggested.

@Inspector 1

Does the transfer case lever line up with the markings on the label plate? Are you pulling against the end of the slot when holding the shifter in low range?
If so, those are clear indications that an adjustment should be made. I just went through this. Getting the lever lined up with the marks straightened everything out.

Ajax MD said:

@Inspector 1

Does the transfer case lever line up with the markings on the label plate? Are you pulling against the end of the slot when holding the shifter in low range?
If so, those are clear indications that an adjustment should be made. I just went through this. Getting the lever lined up with the marks straightened everything out.

Click to expand...

The (H) and (HL) seem to line up fine. I have no problem with either one. I will check the (L) as there may be a bit of a difference. Thank you. I will report my findings.

I would go with (hopefully!) linkage or
Could be the nylon rub blocks inside
the transfer case. Not a big deal to change
but you have to remove it, again not that
Hard. But!!! Once you have it out look at
The chain and now is the time to think
about changing it and while you’re at it
put in new seals.

sue said:

I would go with (hopefully!) linkage or
Could be the nylon rub blocks inside
the transfer case. Not a big deal to change
but you have to remove it, again not that
Hard. But!!! Once you have it out look at
The chain and now is the time to think
about changing it and while you’re at it
put in new seals.

Click to expand...

And if you drop the tcase , also consider a new cooling loop....

Linkage adjustment is probably the first step to resolving your issue but years back I had a manual transmission in an old MG that jumped out of gear unless I held it in and that turned out to be a bent shift fork inside. If someone tried to jam it into a different range hard enough they might have bend something inside and we all know 18 year olds driving someone else's trucks can get brutal at times! And don't forget the histories of these trucks and where they could have been. Someone may have been trying to save their ass jumping out of a ditch in a firefight!