Hey guys, new here, and new to jeeps. Just bought a clean, 1996 Cherokee. It was a southern car no rust or rot and very well maintained.

I ran into a problem I've noticed, and before posting here I did some research.

Here's the deal, shifting from park to reverse or park to drive...good. Nuetral to drive, nuetral to reverse...good. Now reverse to drive or drive to reverse...I get a nice, decently loud bang. Sounds like metal.
When the bang happens the truck does lurch a little.

1. u joints are all good.
2. Read that I should grease my slip yoke. I will, and report back.
3. My rear brakes are shot, I'm going to be replacing them tomorrow. Was told them being super work could potentially make a bang.
4. To me is sounds like slack some where. Because reverse and drive are opposite directions, it has the most slack at that point.
5. With transfer case in nuetral. No bangs, no lurch.

Any ideas? Between the brakes, slip yoke being dry, and possibly the transfer case chain? Only other think I could think of is the rear.
Guy before me did the pinion seal...maybe he didn't retorque it properly?

Any help would be appreciated. I tried to Diag and research as much as possible before posting...I'm not new to forums.

Either way, I appreciate the help. Thanks guys!

 

If the gears were not setup correctly the wear is greatly increased. If the R&P are trashed and you were going to regear to a different ratio anyways now would be the time.

 

Check for excessive backlash in the pinion gear. If there is a lot of slop you can try and tighten the pinion nut up a little and see if the backlash is reduced.

 

could be one of a number of things.
drive shaft u joints ( i know you said they are good, but could be misdiagnosed)
transmission mount
engine mounts
control arm bushings
brake caliper bolt loose or missing (or rear brake problem as you mentioned)
slip yoke but i doubt it
pinion bearing

since you are having a hard time diagnosing it yourself, maybe take it to a shop, have them diagnose it and go fix it yourself if you're capable of it.
it's free and less time involved for you.

 

I don't have a problem diagnosis it.
I know a good deal about cars. I work at a dealer. I just don't want to jump to conclusions and looking for more common problems, if anything.
I've pretty much gone through common things too go wrong.
U joints are good, no play.

I will not have anyone else touch the car. I know how some mechanics and places are. On top of that, you don't learn anything that way.
Motor mounts, sounds too solid/metallic for that too me. And comes from the back of the car it seems. The engine does hop a little when shifting. But nothing too crazy with a pry bar on the mounts.

No control arms in the rear. So can't be that.
Id imagine the transmission is fine, as it shifts fine.

Too me it seems to be pointing to the rear, in which like he said above, I would like to check back lash, get a new crush ring and retorque to spec.

 

So I just went outside, put the transmission and transfer case in neutral. Went under the vehicle, and turned the rear driveshaft back and forth until the pinion would contact the ring.

Seems, excessive. I took a video. I'm not sure how to post it.
To be sure id have to open the housing and check with one of my dial indicators.

I'd say the driveshaft turns a solid 1/8th to 1/4 Inch. 1/4inch at very max.

 

That's not too much play, that's about normal.

 

I may have under estimated the play. I took a video like I said. Looks more like almost a quarter turn. And just turning it by hand you can make it bang.

 

I think you will need a yardstick versus a dial indicator to measure the backlash if you can turn the drive shaft a quarter turn.

 

Well, I believe you'll see more at the drive shaft than at the teeth.

 

With that much play you should also have some in and out movement of the pinion shaft.

 

i know there isn't any control arms in the rear.

that's all i've got without being there, so without sounding rude, good luck.

 

Then why ask

Check that the U-bolts are tight on axle (not just "look")
How are the bushings in springs.
Engine idle not too high?
When was trans fluid last changed? What did it look and smell like then?
Ever adjust TV cable?

Though it "MIGHT" be a bit hazardis, have someone you trust shift form P-R and back and forth while you poke yo noggin under it. Have to do it the same as you "normaly" do, IE. if you don't press brake while shifting, neither should test dummy.

 

Do tell.

 

It could be slack in the chain inside the transfercase.