Clunk on Accel or Decel

[kwjosh]

7 Cherokee, 360, TH400, full time 4wd, low range reduction unit, When travelling on highway at speed, if i take my foot off the gas there is a noticable clunk feel in the driveline, this also occurs when I put my foot back on the gas. Also, there is a patterned vibration at speed, by patterned i mean vibes 3 secs, smooth 3 secs continuous???

[gsmikie]

check u-joints

[kwjosh]

they're fine, this is not a u-joint probelm, that's the first thing I checked out

[Iron Horse]

Tranny mount?

[joe]

<blockquote>quote:</font><hr>Originally posted by kwjosh:
they're fine, this is not a u-joint probelm, that's the first thing I checked out<hr></blockquote>
You prolly have but I can't emphasize enough...have you taken a really good look at the front drive shafts Cardan joint? If you're wrong here and that joint goes south on you while you're goin the road it will remove very large chunks of the transmission case(read: it'll destroy the case) :(
I would take the shaft out, lock in the e-drive and take it for a ride and see if the clunk/vib is still there just to make "sure" it's not the front shaft. If you mis-call this one it gets expensive in a hurry.
If that turns out not to be it I'd look at the trans/x-case mounts and the eng mounts.