Well, here seems to be the first issue popping up with the Jeep.
As soon as I get to work and put it in reverse to park, it made a funny sort of noise as I backed up. Not a grinding, more of a vibration. Put it in park and fine. When I shut it off it made a strange sort of 'thump' at the end.

Went back out after opening up the shop and started it back up. There's a faint, but definitely there, vibration. It's a deeper sort of sound so it 'feels' like something large. It feels like it's coming from around the motor or transmission area. I went out and gave the motor a few revs but it didn't seem to move too awful much didn't hear it out there either. Went back in and shut it off, the 'thump' at the end happened again. Started it a third time and drove it around the parking lot, realized it really only does it on startup and shutdown, plus in any forward gear, only with the foot or emergency brakes applied. Let go of those and nothing.

Had my coworker get in and brake-torqe it a bit, but the motor didn't really move a large amount. I watched the transmission and it didn't seem to move at all. Again, the noise is only seemingly in the forward gears when the brake or ebrake is applied.

Even if I didn't see the engine move a great deal, I'm still inclined to believe it's the motor mounts. They are probably the ones from the factory, they don't appear to be excessively worn out but who knows.
Possibly related issues are that on the odd occasion when leaving a standstill, the mechanical fan tickles something (I assumed it was a piece of the broken fan shroud but if it was the motor mount going bad when whole time, I could assume it would cause this) and sometimes when leaving from a stop, there is a popping sort of noise from the driver's side, which I was thinking might have been a control arm bushing.

What do you guys think? I know diagnosing sounds when you don't hear it yourself is tough, but I might be able to throw pics up later.

 

I had all sorts of clunks and bumps, especially in reverse. My motors mounts didn't LOOK terrible from up top, tough to make a call on my trans mount.


I replaced all 3 and it made a VAST improvement! YMMV

 

It doesn't look too Terribly difficult to change the three mounts, and they aren't all that expensive each. I'm hoping that's what it is because I'm not exactly sure what it would be otherwise.

My first car was a 97 Avenger, the engine crossmember wasn't bolted in the front for maybe two months after I got it worked on by some individual, so I'm leery of this sort of situation. It seems OK to drive at least home, in any case.

 

after driving it home yesterday, it didnt really make the noise after i left the shop at any of the stoplights or other stops i had to make. however it did seem to make extra noise when going over bumps or around corners, especially to the left.

When i got home, i could not get it to make the noise/vibration in any gear.

It also seemed to shake a bit more at 55-60 than i remembered it, though that could just be me worrying about it. I can order new mounts but im not really wanting to drive it back to work today until i get it fixed.

 

If the motor mounts are original on that '96 Cherokee then they have completed the service life

When I changed mine I used my jack to support the load for the rear mount. I used my engine lift to support the load for the front mounts. In both cases a jack stand was used for safety, in case the jack failed.

On my vehicle, I've replaced all the original rubber parts, now it again drives like new.

 

They aren't bad to do at all. Trans mount is a breeze, driver side motor mount also pretty cake. Passenger side was a bit tight but I was able to make it happen without removing anything else. Having a helper to manage the jack and occasionally a pry bar makes things easier.

 

RG,

Here's a write-up to help

https://www.quadratec.com/c/howto/ho...ep-cherokee-xj

If you replace w/ custom after-market (BrownDog, etc.), follow their instructions.

As stated, replace trans mount also and remember to leave the hardware for it loose while doing mm's. Very important.

If you don't wheel or have a heavy foot, rubber mm's should serve you well. Don't recommend cheap ones. Typical life expectancy is maybe a year or so.

Let us know how it turns out.

 

how important is it to do the trans mount at the same time? more like a good idea, or will something go wrong if it waits a week or so?

I ordered some mounts and they came today, but i didnt get a tranny mount. they arent BrownDog, but they should suffice for at least a while enough to get the BDs.

I should probably invest in some PB Blaster this evening at the store, seems like a going trend on these things... I need to inspect the hardware for cracks, right? or is it a good idea to just go ahead and get replacement grade 5 hardware?

 

Hardware is likely fine but certainly give them a good look over. I had no issue with rust / seize on any of mine. Motor mount bolts / nuts don't see as much moisture as things underneath like suspension.


Personally I'd replace all the mounts at the same time but depending on the condition of the trans mount you may be fine. I'd take a look. Regardless you'll want to loosen everything up for the trans mount when you do the motor mounts anyway so kinda silly to not replace what will already essentially be half out....