TJ knocking

[bigdelman]

I own a 1998 TJ 4.0 sport and it knocks twice in quick succession every 4 seconds at 30 mph. I think it is coming from the rear diff, but not sure.
It speeds up the faster I travel and not engine rpm. It is also louder when under load but can be still be heard when slowing down or out of gear.
Pleas can any 1 help?
Thanks John. :???:

 

[SteelHeadz]

First, Check the U-Joints.. And Welcome to Jeepz..

 

[Crazy4diesels]

If it's a big knock, and you think it's coming from the rear diff, I would remove the diff cover and check it out. Your ring gear bolts might be falling out. As they back out of the ring gear the heads start to strike the housing. They will eventually break off and land in the bottom of the pumpkin. The threaded sections will then continue backing out until they, too, fall into the pumpkin. Odds are you have a Dana 35 which don't really have enough ring gear bolts to start off with. They really should have had two more bolts in there. This happened to a guy's Jeep here at work. If I recall, all of his bolts fell out and the Jeep stopped driving. Luckily, the pieces all stayed in the bottom of the pumpkin and did not get chewed up in the gears. Some loc-tite and a set of new bolts and he was all set. Best of luck - John

 

[xt master]

You may have broke one or two teeth in the rear.May want to pull off the dif cover and check for metal shards.

 

[bigdelman]

Much thanks to SteelHeadz, Crazy4diesels and xt master.
The U-J’s, look and feel fine, but I am going to replace along with pinion seals as they to my knowledge are original. I am going to remove the diff cover this weekend and have a look. Also I think it is a Dana 44, as the diff cover is not a complete oval, it is flat at each side.