Hello. I've noticed that my '94 XJ (auto 4.0) makes a hard jerk or thud when I am just starting to pull away from a dead stop. Maybe about the point you'd be going from 1st to 2nd gears. It almost feels like someone bumps into me from behind as it's a noticable jerk and thump. Hoping it's not the transmission. Any ballpark ideas on things to check for? It seems to get less noticable once I've driven a long while and things are warmed up. Thanks

 

With that title, I really didn't want to click on this tread.

Lube up the slip yoke for starters see what that does.

 

With this title I'm not sure we need to be talking about lubing things up either.

 

Reminds me of a common issue with my car. When the rear differential mount or the rear crossmember bushings are worn then shifting gears causes a "thump" from the rear end.

You are going to be looking for something loose from the transmission back to the axle.

Could be the tranny (yep, I threw that one in there) mount, transfer case mount, springs, shocks, etc.

Any loose bolt or worn bushing allowing for movement in the drivetrain.

 

Check you U-Joint's, maniac is right start at your trans and work your way back, give everything a real good shake.

 

What's a transfer case mount? I mean, I've heard of a transmission mount... But yeah...

And wow posts 2 and 3 made me laugh hahaha

 

Just a quick follow up. I never did get around to checking anything but noticed it would seem to make a bump when just backing up also so was leaning towards something being loose and shifting. Then the other day the problem just seemed to go away on it's own.

 

How's the fluid level with the tranny?
Not trying to be a pita but you gotta check the peoples suggestions instead of coming back here and saying you have not checked anything yet. : /

 

U-joints, tranny mount, lube splines at slip yoke, check for over adjusted rear brakes. I personally had two issues with rear end clunks, one of which I cleared up with Metamucil ......seriously though... one I cleared up by lubing the splines on the transfer case output shaft, the other one was caused by one of my drum brakes being over adjusted.....

 

I was going to check it out this weekend. Honest! But then when it stopped doing it I wasn't sure where to look anymore. I'll give it a good lube job today and look around a bit while I'm under there.

 

FYI you gotta drop the rear drive shaft to lube them splines.

 

No you don't. Just move the rubber boot out of the way.

 

Now some one tells me this!

 

Just did mine yesterday and tpday....no thump! You guys are the best! Indeed my driveshaft had to be removed in order to exposed the splines on the driveshaft.

 

I need to do this to my jeep. Can anyone give a good step by step on how to do this spline lubing?