Bad motor mount or transmission mount?

4x4 AG · 2026-01-21T18:25:55-0700

What do they look like when they go bad?

As some know I am chasing things down on this newly purchased rig.

I don’t see the rubber missing, looks there and looks good. Doesn’t flex much when you rev the engine. But between the rubber and the metal you can get your finger in there a ways.

Is that normal?

macleanflood · 2026-01-21T18:30:25-0700

Cheap to replace.

Screenshot_2026-01-05-14-39-37-68_3aea4af51f236e4932235fdada7d1643.jpg

-Mac

4x4 AG · 2026-01-21T18:45:33-0700

I read about those and agree, inexpensive.

I just wonder if mine are bad. Not sure if they are original. I am 3rd owner and last owner had if 8 years and only put 20k on it during that time.

macleanflood · 2026-01-21T18:58:02-0700

If it's been replaced it shouldn't have any cracks.

Everything on these Jeeps that's rubber is more or less compromised after 25 years... mileage be damned.

That's hoses...crank pulley...PCV grommets on the valve cover...just to name a few...

-Mac

4x4 AG · 2026-01-21T20:23:05-0700

Yah I am finding that. But it is something we can work on. So that beats the alternative.

Not sure that it is my roughness and rattles at idle, but may be. Will post a pic when I can and let Yall keyboard diagnose it.

Chris · 2026-01-21T20:28:10-0700

If they're original and your Jeep is as old as it is, they should be replaced as part of preventative maintenance anyways.

This very well could be the cause of your roughness and rattles at idle.

machoheadgames · 2026-01-21T20:30:50-0700

If your engine doesn’t move much, I’d leave them alone. Used old OEM is often much better than any of the aftermarket options.

TJ4Jim · 2026-01-21T20:42:04-0700

4x4 AG said:
What do they look like when they go bad?

As some know I am chasing things down on this newly purchased rig.

I don’t see the rubber missing, looks there and looks good. Doesn’t flex much when you rev the engine. But between the rubber and the metal you can get your finger in there a ways.

Is that normal?

The gap between the rubber and housing would be considered normal but as suggested they do perish with age especially if there were oil leaks contributing. The trans mounts can also be a good source of vibes especially if a PO installed poly mount or a cheap aftermarket oem style.

4x4 AG · 2026-01-22T07:23:07-0700

what are the motor mount lifts folks talk about doing? The Jeep has a 4-4.5" Rubicon Express lift on it. looks to have a skid plate drop spacer, but nothing else.

Just curious what they are for?

macleanflood · 2026-01-22T07:50:04-0700

Motor mount lift might let you get rid of the spacer on the skid plate. But you probably need a slip yoke eliminator, a new rear driveshaft and adjustable control arms to be completely vibe free.

I have a JKS spacer MML and stock style Anchor mounts. I have a 1" body lift, SYE, and a UCF tummy tuck skid plate... bringing the transfer case up.

Lots of articles in the resources section you should read.

-Mac

4x4 AG · 2026-01-22T07:53:51-0700

macleanflood said:
Motor mount lift might let you get rid of the spacer on the skid plate. But you probably need a slip yoke eliminator, a new rear driveshaft and adjustable control arms to be completely vibe free.

I have a JKS spacer MML and stock style Anchor mounts. I have a 1" body lift, SYE, and a UCF tummy tuck skid plate... bringing the transfer case up.

Lots of articles in the resources section you should read.

-Mac

yah that sounds more serious than a 16 yo vehicle needs. Was just curious.

For now the Jeep is my oldest son's first vehicle. I told him if he ever wants something else I will take from him. Always loved the LJ's.

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