95 XJ Auto - trouble moving forward from a stop

1995 2wd Cherokee Country Automatic 150k miles

Everyday for the past month.. crank the jeep, put in reverse and rolls back just fine. However, once in drive she has trouble moving. I have to really give her gas to move. When I do give a slight amount of gas, I hear a metal crunch noise coming from the back as if something is trying to move but can't.

Once warmed up and driving for about 20 minutes it seems to be fine. After a long drive, if I stop the vehicle and then crank it up again a short time later, the problem is back but even worse. It really takes a long press of the pedal to get her to move.

It never bogs on me and seems to move easily in all other gears. Funny thing -- when it sits in the sun for a few hours the problem strangely isn't there.

Tranny shop said my trans was fine four months ago. I changed the filter and gasket about 3 months ago and filled with lucas stop leak due to seals leaking. Fluid levels are fine and hasn't leaked since.

Any ideas?

check your rear u-joints and take your cover off your diff and look at the gears. Clean out the case, brake cleaner works great for cleaning in the case. Check it for excessive wear/play(bad mesh/worn mesh) in the gears and look for any chipping/scaring, cracks, etc.

Also take your drums off and make sure none of your brake hardware has come loose and is catching on anything make sure the ebrake cable is not just hanging out to as that can catch alot of stuff in there.

The AW4 is controlled by the TCU (under driver side dash) Pull the fuse and see if it shifts manually. If so, probably lies your issue.

Which fuse? .. I read somewhere 13, but haven't found a clear indication yet. Photo of my fuse box attached.

I would recommend putting a pressure gauge on the tranny. When in reverse the pressure is higher and I have seen many trannys that would only go in reverse for the first minute or so, then as it warmed up the seals in the pump would seal and it would work fine in drive. That said, it normally doesn't make a crunching sound.

A crunching sound could be a bad ring/pinion or possibly a bad rear brake.

You say after it gets warmed up and driving for 20 minutes it goes away. So if you can't go forward, how do you drive for 20 minutes? Does it pop, then everything if fine until you stop and then start up again?

Yeah.. the crunching noise may not be directly related. I'll examine the drums when I do the fronts in the next few days.

To be more specific about the problem... From a stop I can move forward by pressing the gas, but it doesn't move on it's own in drive. In fact, I can stop at a stop sign when the vehicle is in drive and not even have my foot on the brake. It just sits there until I give it gas. I live in Atlanta so I have a lot of start stop start stop. About 15-20 minutes of city drivin will make the jeep act normal wherein I have it in drive and I have to put my foot on the brake to prevent it from moving forward.

I'm worried it's the trans so I was going to take it back to the man to have a look. The last time he mentioned he tightened my torque converter bolts. Is it possible it's related to this? I'm doing the front brakes and rear diff fluid change very soon and will post some pics of anything suspect.

old_man said:

I would recommend putting a pressure gauge on the tranny. When in reverse the pressure is higher and I have seen many trannys that would only go in reverse for the first minute or so, then as it warmed up the seals in the pump would seal and it would work fine in drive. That said, it normally doesn't make a crunching sound.

A crunching sound could be a bad ring/pinion or possibly a bad rear brake.

You say after it gets warmed up and driving for 20 minutes it goes away. So if you can't go forward, how do you drive for 20 minutes? Does it pop, then everything if fine until you stop and then start up again?

Click to expand...

x2 on ALL of this. I do believe your crunching sounds and forward movement problems are not related.

My first stop would be to pull the rear drums and have a look-see, drums don't grab as hard going in reverse as they do going forward. it's possible that you have something bound up in the drum keeping the shoes from retracting all the way.. first and foremost if you are lifted would be the ebrake cables being out of adjustment, they need to be adjusted after a lift because the cables will be pulled tight, like having the ebrake pulled a bit. This would also explain why the problem goes away after driving for awhile, as the brakes heat up the become less efficient. After you've been driving enough to make the problem stop, try putting your hand on the rear wheel near the center, if it's hot enough that you don't want to keep your hand there your rear brakes are probably dragging.

It could also be related to the torque converter slipping badly, but that would generate tons of extra heat and would likely make it run hot because the stock transmission cooler is inside the radiator.

Let's say I take an infrared thermometer and check the temps on the trans... what should be normal? what should be unacceptable? Usually temps run at 190-210 when highway driving. In traffic we go up to 220-230ish range.

I do have a noise similar to the loose flex plate torque converter bolts.. that may be at play. I also have an exhaust leak at the cat and the exhaust manifold so noises are hard to diagnose.

The TCU fuse is under the pass side dash close to the TCU.

Didn't have to cut the TCU afterall... I've pinned it down to the e-brake cable. When I pull the e-brake and then release... somehow it gets stuck won't disengage. Simple solution is to just not use the e-brake. I haven't used it in a few days and have yet to experience forward movement issues. Will be examining all four brakes tomorrow.