cali93zj

Hello everyone im new to this fourm. Im 17 years old and recently just bought my first jeep a 1993 Jeep grand cherokee Laredo 4.0 straight 6, 150k miles.. I knew nothing about jeeps till i started reading these fourms.... I wish i had read up before i made a purchase! My ZJ runs good and all but i have recently been researching transfer cases and have learned it has the infamous 249 transfer case): . the car dosent seem to bind when turning or anything and it did not seem to have a problem makeing it up my muddy/ very steep drive way after a heavy rain unlike my moms bronco that will get stuck unless 4x4 is engaged . My question is How do i know when the 249 transfer case is failing? and also when it does fail will the car be drivable? when the transfer case fails does the car become rwd ? or is it permantley in 4x4 ? These probably seem like very stupid questions too you guys but i had trouble finding any answers searching through the threads ... Thanks so much any help would be great!

dave1123

Welcome to CF!

Okay, I'll get your education started, LOL. The 249 t/case is a full-time 4WD with a viscous clutch to make up for differences in axle speed caused by cornering or traction differences. It applies power to both axles equally at all times. The viscous clutch is a sealed unit in the t/case with it's own contained fluid and friction plates. When the differences in traction between the axles is excessive, the clutch heats up, causing the plates to burn. They get sticky and don't release when they should, causing a binding and wheel hop when cornering sharply. I've never heard of a case where the clutch has failed completely, but if it does, you will still have rear wheel drive.

The problem with the VC is it's an expensive thing to replace, costing between $300 and $400 for the part, and disassembling the t/case to install. That's why when faced with this problem, most guys opt to install a part-time case like a 231 or 242. It is important to have all 4 tires the same size with the same amount of wear on them to limit slippage causing heat.

The 249 was designed for ease of operation where the driver doesn't have to shift to 4WD when road conditions change. It's great for people who don't want to worry about it and just drive.

Any other questions?

cali93zj

thanks so much Dave that calirified things up.. so pretty much as long as i dont have any binding or turning problems the VC is probably good? whats the best way to test that its functioning properly? i will defientley be switching it out for a 242 when it does fail.. which will probably be soon considering its has 150k miles

dave1123

Do a couple of sharp figure-8 turns slowly and see if it binds or causes the wheels to hop. This will be caused by the clutch not slipping and absorbing the different axle speeds. You'd get the same feeling with a 231 or 242 in part-time 4wd on dry pavement. That's why I like the 242 so much. It has a full-time option that replaces the VC with a differential. The only problem with that is if one wheel spins, you go nowhere. THEN you shift to part-time.

If you're going to eventually swap t/cases, you might want to look for the right one now. Check out http://jeepforum.com/forum/f13/trans...1-np242-685644 for the one that fits your jeep.

AdidasCJ

As explained above, just to add...

The 249 is a very stout transfer case! Reliable and robust. The VC is the drawback of the case when it DOES go out. However, NOT the end of the road for your jeep if it does fail on you.

You can rebuild the case but the VC is a tad pricey...

Or

You can hunt your local junk yards for a 242 or 231 transfer case where some will bolt right in and others only requiring to shorten the rear drive shaft slightly. (local driveline shop can help with this, again, not very costly.)

Just as an example, I pulled the 249 from my ZJ, NOT because it failed but because I wanted a select-able 4wd case. I scoured the junkyards for a few weeks and found a 242 that bolted RIGHT IN for about 120 bucks at my local pick a part junk yard.

There is a LOT of information and write ups for the ZJ's and Case swaps. Read Read, Read again then ask questions.

dave1123

I'm glad you cleared that up. The 249 is not a bad case, it's just when people start to have trouble with it, they sell the jeep, then WE get their problems.

BTW, what amazes me is nobody ever seems to have problems with the drive chain. The only time I ever heard of a chain breaking was in a Wrangler and that broke the case wide open! Of course he got some air and came down hard! LOL!