I just put on 4 new tires. This 1999 Cherokee sport had 235/75/15's on it. I had another Cherokee that had 215/75/15's. I had two of those laying around so I figured I'd put those on the front and 235's on the rear.

It snowed today and I haven't been able to get the 4WD Part Time out of gear. I drove like 20 miles and when I got home I'm guessing the gear box was so hot it was smoking.

Someone tell me WTF is going on.... to summarize I have 215/75/15's on the front axle and 235/75/15's on the rear and cannot disengage from 4WD.

 

why on earth would you think it's a good idea to mismatch tire sizes? And then proceed to put the vehicle in 4wd?? The difference between those 2 sizes is an inch and a half... That's a HUGE no no in 4wd vehicles...you ****ed up your transfer case doing what you did man haha.

 

Yes that is not a good idea, however if you put the lever in 2WD and back up a little it will probably shift out. It is only a little spring in there that disengages it

 

i asked two mechanics... they didn’t say absolutely not, they didn’t say it’s a problem. Obviously the ideal plan would be all the same size.... oh well.

 

if the transfer case is ****ed, i’m Guessing I need to disconnect that drive shaft?? What’s next, get one from a junk yard?

 

Apparently they WERE NOT MECHANICS. This has been a very well known truth for over a hundred years of 4x4 development. Fire those guys... lol

 

The driveline is in a bind, preventing shifting out of 4x4. Lift one wheel, front or rear off the ground to relieve tension, then try again. Or drive it onto dirt/grass and try shifting.
Driving in 4-Part-Time with mismatched tires will create excessive heat in transfer case. And since there is only just over a quart of fluid in it, and has limited cooling ability, it does not take long to toast the fluid and bearings.
If it was run in 4 Full-Time with mismatched tires, it would still make more heat than normal (due to internal differential) but would likely be just fine.

 

Thanks man..... Trying to save a couple bucks may have cost me a few bucks....

 

as is usually the case man. Don't go back to those 2 mechanics.... try the recommendations above. 20 miles may not have been enough to damage everything, but I would drain the fluid and see how it looks.

 

Oh and where did you have the tires mounted? The shop that did it should have noticed and told you it was a no go...unless one of those mechanics mounted them lol

 

And once again it comes full circle why paying a little more an hour for someone who actually knows what they are doing is so important.

 

Personally, if you don't hear crunching noises the tcase is not messed up. Just in a bind. If you try what I said, it will probably just unshift itself when you back up slowly

 

My 4WD indicator is finicky and does not always illuminate on the dash when engaged, I forgot to shift out of 4H after some offroading and drove about 100 miles home on the highway in dry pavement, only noticed when pulled into driveway, transfer case still fine but then again I had matched 32 BFGs all around, good luck.