AMC Eagle Den Forum

The Shop => 4X4 and Driveline => Topic started by: drock87 on September 16, 2013, 05:21:51 PM

Title: Thumping feel.....tranny mount, ujoints, engine mounts????
Post by: drock87 on September 16, 2013, 05:21:51 PM
There is a similar thread, but I feel the "thumping" underneith me when going over bumps, coasting (especially around a turn), in reverse, and especially in 4x4. Now...If I'm in 4x4, it is accelerated if coasting, but under heavier acceleration, it is much less noticable. In another forum, the throughts were either the front driveshaft slipyoke or tranny mount. Thoughts?
Title: Re: Thumping feel.....tranny mount, ujoints, engine mounts????
Post by: IowaEagle on September 17, 2013, 06:29:54 PM
I would check the transmission mount first.
Title: Re: Thumping feel.....tranny mount, ujoints, engine mounts????
Post by: Gil-SX4 on September 18, 2013, 01:10:05 AM
Check the muffler first, if you really don't hear it at faster speeds but hear it at slow speed when hit-ing bumps in road, check drivers side rear bracket before rear wheel, drivers side before pipe takes the loop over rear shock tower, or rear wheel shaft.
Title: Re: Thumping feel.....tranny mount, ujoints, engine mounts????
Post by: Gil-SX4 on September 18, 2013, 01:18:52 AM
Thoughts? If other site is the "Nest" throw any idea's of info in the trash where it belongs!
Write me and tell me where the thump sound seems to come from, back front, drivers side, or left side.
Get it, if you can on a lift, check trany mounts just by pushing up at trany back end, it really sounds like your pipe bracket or clamp is broken. 
Title: Re: Thumping feel.....tranny mount, ujoints, engine mounts????
Post by: IowaEagle on September 18, 2013, 08:55:29 AM
Good suggestions Gil.  Uni-body cars tend to transmit sounds to other places in the car were the problem is not at.  One test is to put it in first gear and then romp on the gas pedal, if there is a lot of shudder and the gear shift really vibrates it may be the trans mount.
Title: Re: Thumping feel.....tranny mount, ujoints, engine mounts????
Post by: 1985amceagle on September 19, 2013, 06:43:26 PM
Quote from: Gil-SX4 on September 18, 2013, 01:18:52 AM
Thoughts? If other site is the "Nest" throw any idea's of info in the trash where it belongs!
Write me and tell me where the thump sound seems to come from, back front, drivers side, or left side.
Get it, if you can on a lift, check trany mounts just by pushing up at trany back end, it really sounds like your pipe bracket or clamp is broken.

the other forum was Evolution, here is the topic: http://forums.amcevolution.com/viewtopic.php?f=14&t=1632 (http://forums.amcevolution.com/viewtopic.php?f=14&t=1632)  if it was on the nest, it looks like steve threw the forum away again. (http://forums.amcevolution.com/images/smilies/download%20(11).gif)   Drock, how close is the driveshaft to the tail pipe? could the drive shaft be hitting the exhaust pipe? ???
Title: Re: Thumping feel.....tranny mount, ujoints, engine mounts????
Post by: IowaEagle on September 20, 2013, 01:42:44 PM
Yes, it could be one of several things.  A close examination under the car is in order.  The exhaust pipe by the trans/transfer case could cause that.
Title: Re: Thumping feel.....tranny mount, ujoints, engine mounts????
Post by: EAGLER on September 20, 2013, 05:03:59 PM
it also could be a bad tranny mount it can cause that sound or the exhaust pipe as doug said
Title: Re: Thumping feel.....tranny mount, ujoints, engine mounts????
Post by: drock87 on September 26, 2013, 08:11:25 PM
Hi. Thank you for all of the replies; sorry I have been quiet. My exhaust has seen better days. My hanger near the rear is, well, gone. However, the shifter does move around a little (but, it's always done that) in first. It does get more noticable in 4x4. I notice it more like if I'm coasting than under acceleration...like sort of right under my driver seat. I did get underneath the car and "shook things around a little" with no conclusion. I also notice it if I"m on an off ramp coasting around a turn.

Oh, everything vibrates pretty bad in reverse.

Do you really think that could be the exhaust th
ough?
Maybe have my mechanic who did the rear end and the transfer case look at it? I just don't want to fcuk something up by driving it too much!
Title: Re: Thumping feel.....tranny mount, ujoints, engine mounts????
Post by: IowaEagle on September 26, 2013, 08:16:04 PM
Still sounds like the trans mount is suspect.
Title: Re: Thumping feel.....tranny mount, ujoints, engine mounts????
Post by: drock87 on September 27, 2013, 08:19:41 AM
Iowa---how big a deal is that?
Title: Re: Thumping feel.....tranny mount, ujoints, engine mounts????
Post by: IowaEagle on September 27, 2013, 09:51:05 AM
If you get a new one, it will probably be for a manual transmission application as the one for automatics is rarer than hen's teeth.  You can modify the manual one by removing the mounting studs on the bottom side and then use the factory (or better yet new) fasteners.  See the picture below, numbers 2 and 3, for the difference.  Replacement is fairly simple with hand tools and a jack.

(http://wiki.amcevolution.com/images/9/9b/84880087.jpg)
Title: Re: Thumping feel.....tranny mount, ujoints, engine mounts????
Post by: drock87 on September 27, 2013, 01:15:26 PM
This almost looks mythical...is this something I can actually do myself??
Title: Re: Thumping feel.....tranny mount, ujoints, engine mounts????
Post by: IowaEagle on September 27, 2013, 01:51:48 PM
You should be able to.
Title: Re: Thumping feel.....tranny mount, ujoints, engine mounts????
Post by: drock87 on October 15, 2013, 03:22:54 PM
Hey all! Finally had my transmission mount replaced; that was the culprit! I used the manual tranny mount available from RockAuto, and had my mechanic install for me. Feels SO much better!
Title: Re: Thumping feel.....tranny mount, ujoints, engine mounts????
Post by: IowaEagle on October 15, 2013, 03:25:55 PM
A Thumbs up for perseverance and getting it solved.