CAEMI

I've got a mystery clunk.

I start the engine after sitting overnight, put it in drive or reverse, and get a clunk...feels like kinda under the drivers seat or maybe under the trans tunnel.

It does not do it again...unless it sits for a while. Then I get one clunk. It is a distinct clunk...but just one.

Going down a washboard dirt road I get stacato clunks but figure that's normal.

1991Jeep_Man

It's simply an old transmission doin its thing. Mine does the same thing after sitting for while.. especially if it is cooler.

CAEMI

I'm hoping thats it. Feels kind of like a control arm but when I look them over, they look perfect. Can't find a thing out of place under there.

1991Jeep_Man

Is the tranny mount tight? Also, try running a bottle of Lucas Tranny Oil in it. That's what Im getting ready to do.. You figure years of service, any tranny fluid changed or not is gonna develop some crap on the valves. Lucas should clean that right up.

boy_named_sue

Does it "clunk" into gear immediately when you shift into gear, or is there a pause? Could check for low or bad tranny fluid, or a gunked up filter. If the fluid's not moving properly, one of the tell-tale signs is a hesitation when shifting into gear, especially when cold. Had that issue a couple of times. Also, when driving down the road, if you take your foot completely off the gas and tap it, can you reciprocate your "clunk"? if so, perhaps check the u-joints on the drive shaft and/or rear differential.

Diesel

Bad idea.

http://www.bobistheoilguy.com/images/lucas/lucas.htm

95THORxj

wow!!! good info dude. never even thought of that.

CAEMI

I'm gonna take the xj for a drive today and check out the trans behavior. It seems to shift crisply and I have not noticed any delay in engagment, but I'm going to check it out.

Diesel: Thanks for the link debunking, again, the oil additive fraud business. Like K&N filters, it can't be repeated enough that this stuff is snake oil.

lurk520

Mine clunks when ever shifting from reverse to drive, but I read a tip on here that works for me, shift into reverse-back out of your driveway or parking spot-hold your foot on the brake for about 3 seconds-then shift to drive. I think my trans mount is shot though, so I'm hoping to replace it soon along with the fluid and filter, I will let you guys no if it resolves the issue. As for the Lucas additive, I used the Lucas engine oil stop leak on my last oil change and it seems to be working for me, my oil loss seems to be gone or at least dramatically slowed down, and my oil doesn't appear to be any weird color either, but who knows, maybe it really is bad......

thelittlebrutethatcould

mine clunks when going from reverse to drive, never heard of the braking thing, i'll try that...but i've also got the braking clunk too, and other threads say that it could be a control arm bushing, so that sounds good to me...hopefully something this simple is all that is wrong with both of ours