I think I narrowed my problem of grinding between shifting up to 2 and down from 3 to the synchronizer; now looking around more and researching people recommend this and that for MANUAL transmissions, like redline, MTL, etc.
My question is what about an automatic? I have an AW4 (i think) in my 96 xj sport 4.0l and previously used Dexron/Mercon III. Maybe I should add some of the synchromesh hullabloo?
I also see people using 70w80 gear oil instead of ATF, but again, that was for manuals so for an automatic trans I can't find much info.
I am not leaking, I change regularly, but at this point im delaying the inevitable rebuild. 50mi/day commutes

 

Dex/Merc only in the AW4. It doesn't like other fluids.

I'd find a replacement and have it rebuilt now.. run it until it goes then swap it out.

 

dang, thats what i didnt want to hear. Should I just grab a rebuild kit and weekend warrior it? or just buy a rebuilt one? i have a backup car but id rather not drive that since its even beater-er than my XJ

 

you 100% have an AW4 trans in your XJ, they only came with an AW4 in the automatics. also Dex/mercIII is spot on like stated. These auto trans are very well known for outlasting the jeeps themselves and also not being very valuable to re-sale simply because they are beyond plentiful IF you do need to replace it. For what price you might pay for a used one i'd simply find the lowest mileage used trans available that was NOT in a wheeling rig and weekend swap it and be done with it - just my $0.02

 

Appreciate it; yeah I was doing more research and saw other people with the same issues, rebuild kits cost about the same as a used one, and prebuilt ones cost triple, which aren't worth it. Gonna try some junkyards around me and ebay/craigslist/everywhere else.

Appreciate it everyone!

 

I cant stress this enough - dont buy used parts off someones offroad jeep - wheeling jeeps just aren't cared for as well as they should be typically in my experience.

 

You 100% sure it isn't bad motor and/or trans mounts?

 

I'm not sure what would be grinding during shifts on the auto, since all the shifting is done with clutches and not gears locking in/out. There are no synchros in the automatic. Do you get same grinding in 4-lo?

If you do look for a used one, beware there were two changes over the years. Based on your moniker, you'll want a 1991-1996 AW4.
https://www.naxja.org/forum/showthread.php?t=1053970

 

I'll double check that when my brother comes home with it, would it make a difference if it seems to happen relatively more often when turning slightly? going around a 45 degree curved road it seems like it back out a front axle so it gets louder, then goiung back straight it seems to turn back to normal.
Again, this grinding/vibrating is not super loud or extremely grindy, just a grumble and medium loud on low gears.
When idling it does a low grumble but when i give it a small tap of gas in park/neutral it fixes itself
When I'm accelerating its fine, when it up shifts to 2 it grind for a second then stays relatively normal, up shift to 3 and its no grind sounds perfect, 4 perfect, down to 3 perfect, down to 2 grinding for a few seconds until i keep tapping the gas to quiet it down until it relaxes to semi-normal, down to 1 its fine for the reset of the drive.
THERE IS SOME TIMES from 2->3 it drops back down to 2 at a low grumble as if it doesnt want to go to 3 so I have to give it a bit more gas to stay in 3 but that usually happens when going up hills.

Wait that throws a whole wrench in my theory then... I thought autos had the synchros too?? NO grinding in any 4wd scenarios, hi or low (unless I dont put it all the way into position)

 

heres what it looks like, yes i know the hanger for the exhaust is missing lol

 

Maybe get the exhaust off the cross member and see if the noise goes away

 

i wont die if i go around the block without a crossmember will i? or should i threw the rear on jacks

 

I was going to reply but thought better of it..

 

The only thing I could think of as a quick test would be to wrap a welding glove (high temp resistant) around that section of exhaust and go for a very quick test drive to see if the noise goes. Lifting the rear on jacks is a pretty dangerous idea, one slip and you have a car in 2nd/3rd gear above you. Also testing when not under load may produce a different result. Removing the cross member will remove the transmissions support so also a bad idea.

 

Boy, I knew I was stupid but apparently I cant read while at work lol...
Ill try this tomorrow, that would explain the sound if it was the exhaust hitting the crossmember; still hunting for transmissions in the area either way