Ad blocker detected: Our website is made possible by displaying online advertisements to our visitors. Please consider supporting us by disabling your ad blocker on our website.
Hello. I need some help. My 88 GW has started idling rough, but ONLY in reverse gear. It is so weird. It fires up fine, idles smooth in neutral and drives without incident. However, when I shift to reverse, it starts vibrating rough, even as I am pressing the brake. When I give some gas, it shakes as I am reversing, but then does okay with a little momentum, but then when I shift to drive, does perfectly fine. I read it might be an engine mount issue, but it does not seem to be that to me. I would greatly appreciate your collective wisdom!
Have the hood open with somebody looking at the engine from the side, NOT from in front, and then while pressing the brake pedal FIRMLY and the parking brake engaged, shift it to reverse. See if the engine torques over. Do the same drive. You can also apply a very small amount of throttle to see if it really moves.
The engine will move a small amount with good mounts, but with bad mounts, its normally pretty obvious that it moves more than it should.
the transmission has a mount too. Honestly the mounts on these engines are flat solid blocks of rubber.. Unless they rotted comoletetly or the metal part rusted off i doubt engine mounts are bad.. They rarely go bad on these trucks.. Unlike those round hollow mounts on the newer grand cherokees
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)
candymancan wrote:the transmission has a mount too. Honestly the mounts on these engines are flat solid blocks of rubber.. Unless they rotted comoletetly or the metal part rusted off i doubt engine mounts are bad.. They rarely go bad on these trucks.. Unlike those round hollow mounts on the newer grand cherokees
You must be lucky. I've replaced engine and trans mounts in all three of the FSJs I've driven, usually one of the first things to get done. Polyurethane ones seem to be holding up pretty well.
Ron
2005 KJ, Hit-n-Run, 2am 6-17-2012, Totaled.
1977 SJ J10, 4v360, T18, D20, 37x14s, SOA & SF on tons, still ugly.
1978 SJ Wagoneer, 4v360, QT, 33x12.5s, lift by Sawzall NOT Running
1977 SJ J10, SniperEFI 401, QT, D44s, 31X10.5s
2006 KJ
Mars wrote:One man's trans leak is another's penetrating oil
candymancan wrote:the transmission has a mount too. Honestly the mounts on these engines are flat solid blocks of rubber.. Unless they rotted comoletetly or the metal part rusted off i doubt engine mounts are bad.. They rarely go bad on these trucks.. Unlike those round hollow mounts on the newer grand cherokees
You must be lucky. I've replaced engine and trans mounts in all three of the FSJs I've driven, usually one of the first things to get done. Polyurethane ones seem to be holding up pretty well.
x2 I've had to replace torn engine mounts on almost every FSJ I've owned. Heck, I've had to replace my trans mount twice on the one I own now.
-Jonny B.
1979 Cherokee Golden Eagle - UNDER CONSTRUCTION
7" lift, 35x12.5x15
AMC 401 - Pro-FLo 4 FI
NV4500/NWFBB/NP205 - Triple Stick'd
F D44 - 4.10, Eaton E-Locker
R M23 - 4.10, Detroit Locker
1979 Cherokee Chief - Parts
1979 Cherokee Chief - Parts
1979 Wagoneer - Sold
1981 Cherokee Chief - Cubed
Have the hood open with somebody looking at the engine from the side, NOT from in front, and then while pressing the brake pedal FIRMLY and the parking brake engaged, shift it to reverse. See if the engine torques over. Do the same drive. You can also apply a very small amount of throttle to see if it really moves.
The engine will move a small amount with good mounts, but with bad mounts, its normally pretty obvious that it moves more than it should.
for the one man (person) operation : put front bumper against a utility pole ( a large one), put in D(rive) and while standing on the side give it some gas by pulling the throttle cable, it is always a surprise to see the engine trying to lift itself from the engine bay
Michel
74 wag (349 Kmiles... parked, next step is a rust free body)
85 Gwag (229 Kmiles... the running test lab)
candymancan wrote:the transmission has a mount too. Honestly the mounts on these engines are flat solid blocks of rubber.. Unless they rotted comoletetly or the metal part rusted off i doubt engine mounts are bad.. They rarely go bad on these trucks.. Unlike those round hollow mounts on the newer grand cherokees
You must be lucky. I've replaced engine and trans mounts in all three of the FSJs I've driven, usually one of the first things to get done. Polyurethane ones seem to be holding up pretty well.
x2 I've had to replace torn engine mounts on almost every FSJ I've owned. Heck, I've had to replace my trans mount twice on the one I own now.
Interesting. then maybe mine were replaced at ine point.. but they look brand new still.. to me its weird how a solid block of rubber would fall apart unless it got dry rotted or melted from oils and stuff on it.
I guess i take my statement back.
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)
For those of us who wheel real hard, it's a good idea to put a small chain around the frame and engine side of the mountain. If you hit it hard enough the fan can get into the radiator and ruin your day.
Elkman06