My truck never had a problem shifting into and out of 4 wheel low until after the trans was built. Now when it I shift into 4 low I need to be rolling slowly. But when I shift out of 4 low the truck starts to grind and I have to shut it off. When I turn it back on it stops grinding and its out of 4 low. Any ideas on what could cause this?

Going into and out of 4 low, I think you are supposed to be stopped and in "N". That's what I do and it works good every time. Is the transfer case full of fluid?

jb

Going into and out of 4 low, I think you are supposed to be stopped and in "N". That's what I do and it works good every time. Is the transfer case full of fluid?

jb

I do the same and have never had a problem. Never tried with the truck moving though.

Ya, you have to be stopped and in neutral when shifting into and out of 4-low. 4-hi doesn't matter, you can shift on the fly. but again with 4-low, you must be stopped and in "N". If you were stopped and in "N", then i would just call the tranny shop and make an appointment. You might do that anyway, if the transfer case was grinding, you might wanna have those gears checked out.

When I'm not moving and in neutral it won't work, I will blink on 4 low for a couple seconds then it goes back to 2 hi or 4 hi (depends what the truck was in before). I did a search and found in this section of the forums where a couple other guys had to be rolling slow put the truck into N then hit the 4 low button and it would work. I think I'm goign to take it to the dealer for warranty work. Nothing has been done to the t-case so it should still be covered.

Every one I've owned I had to be rolling slightly in N.

Every one I've owned I had to be rolling slightly in N.

X2 and it won't shift if you're moving too fast.

the owners manual says you can do it while moving but not more than 2~3 mph it recomends to do it at a dead stop

Neutral, and free to roll, but not rolling fast, just loose, like one tire revolution max.

I've always done this because I came from cast iron all gear driven NP208 transfer cases, and you HAD to allow for slight wheel movement, in order to mesh up, without messing up, the gears.

I found the electronic shifters with the chain drive still benefit from being free to roll. Eliminates binding.

While stopped, drive to neutral to reverse always works for me. Don't stay in neutral too long or you'll definitely be grinding some gears when the now moving transmission engages the fully stopped transfer case.

Neutral, and free to roll, but not rolling fast, just loose, like one tire revolution max.

I've always done this because I came from cast iron all gear driven NP205 transfer cases, and you HAD to allow for slight wheel movement, in order to mesh up, without messing up, the gears.

I found the electronic shifters with the chain drive still benefit from being free to roll. Eliminates binding.

Fixed it for you.

The NP205 was all gear driven cast iron case, the NP203 had an all gear reduction box made of cast iron with a cast iron chain drive and a aluminum encased differential assembly (Heavy SOB), The 208's were the first gen all aluminum case with a chain drive (but a MUCH better gear reduction).

As for the proceedure, yes, that seems to work on my 80 Chevy with the Cast Iron T-case and on my 2006 GMC.

Yes... thank you Leadfoot. You're right. NP205, not 208.

Almost 30 years have gone by since those units were new, kinda lost track.

Just thought of something. When I built the trans I drained the transfer case of the ATF and filled it with three quarts of synthetic 5w-30... Could that some how be causing this? I doubt it b/c so many guys run it but I was just thinking.