2000 wj 42re transmission thump 3>4th gear

[rabdav]

Hi, has anybody had a problem that on acceleration at between 40-50 the last gear changes comes in with a thump (but not every time), if I release the throttle just before the change the thump doesn't happen !! sometimes it feels like it is going into 4th & out & in again
I have changed the trans oil/filter, checked the cable adjustment & the band adjustment, changed the output speed sensor, help please

[91 bird]

could be a loose u-joint or a little slop in the rear dif ring gear.

[fredjacksonsan]

My 2004 thumps slightly when it goes in to lockup, you can feel when it locks up depending on how much throttle you're giving it. Usually under really light acceleration it will go in at about 47mph; if I'm accelerating onto the highway it'll be as high as 60 or 65 and is not as noticeable.