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Weird 4l60e problem

Posted: Fri Mar 06, 2015 6:50 pm
by Pontiac_Puller
Helped out a friend with his truck, it's a 1994 Chev half ton 4x4. He had a leaky cooler line and it dropped all his fluid on the highway. By the time he got home he had burned out the 3/4 clutch pack. I tore it all apart, found a cracked, (but not broken) sun shell, as well as the burnt clutches. I replaced everything, flushed all fluid from everywhere, got him back running. Everything worked as it should.

A few months went by and then he called me, saying reverse was acting up. I stopped by and took it for a drive. Everything feels fine going forward, goes through all gears as it should. Even when you put it in reverse, it feels fine, but it wont roll backwards on its own, and you really have to give it gas to get it to move. As soon as you let off it stops, as if the brakes are half stuck on. I put it up on a jack, took the tires and drums off, and it still acts up in reverse, so it's not the brakes.

I can't help but to think it's in the transmission, but have not found any known problems that match my symptoms. Has anyone encountered this?

Re: Weird 4l60e problem

Posted: Fri Mar 06, 2015 7:15 pm
by ingram
I have some experience with that transmission and always interested in solving problems with them. I don’t think it’s a transmission problem. Might be in the transfer case or some other part of the driveline. Let us know what you find.

Re: Weird 4l60e problem

Posted: Fri Mar 06, 2015 7:57 pm
by Pontiac_Puller
My next move is to put it up on a hoist and pull the rear drive shaft to see if the axle is binding. If not that, I'll pull the T-case and see if it still has issues. I do have a spare case if it's the problem.

Re: Weird 4l60e problem

Posted: Sat Mar 14, 2015 8:06 pm
by TexasT
If it has an NP246 transfer case, check the fluid level. They are known to have the pump rub a hole in the case letting the fluid out. Then the case pretty much grinds itself to death with no fluid.

Re: Weird 4l60e problem

Posted: Tue Mar 17, 2015 2:26 am
by Pontiac_Puller
NP241, and does not appear to have any issues.