[Timmybung]

'97 "Sport" w.4.0l, 113,000 miles
So a couple weeks ago I was backing out my my brothers driveway and he noticed that the front driveshaft (the one that goes between the transfer case and the front diff) was spinning. At the time I told him that was normal, but upon reflection that doesn't seem right. Plus in the last couple weeks I've noticed a noticeable drop in MPG (down to about 10!) and it seems stiff when turning tight in a parking lot (like when 4wd is on)- could my 4wd be stuck on? I did a bunch of searching and couldn't find any likely culprits (could be that I wasn't searching for the right keywords)- any suggestions?
Thanks-
-Tim-

[Jerry Bransford]

The front driveshaft is being spun by the front axle when you're in 2wd, not the transfer case. The front driveshaft always spins even in 2wd because the wheels connect to the axle shafts which connects to the ring & pinion gears which spin the front driveshaft 100% of the time. The front driveshaft is disconnected inside the transfer case whenever you're in 2wd.

[GOLENJEEPTJ]

You would also feel a big difference in low speed turns if engaged.

[NotURMailman]

^x2... you don't have a problem (other than thinking too much).

[BlueFlame]

It's easy to check.
Jack up one front wheel.
Spin the tire, if the driveshaft spins, you are not in 4wd.

[dzride]

Originally Posted by BlueFlame

It's easy to check.
Jack up one front wheel.
Spin the tire, if the driveshaft spins, you are not in 4wd.

Like been mentioned before the drivesaft will always spins. You need turn off engine,jack up front wheel and put in gear if wheel will spin in 2wd you're fine.

[NotURMailman]

Originally Posted by dzride

Like been mentioned before the drivesaft will always spins. You need turn off engine,jack up front wheel and put in gear if wheel will spin in 2wd you're fine.

Blue Flame's point it that you won't be able to turn the front drive shaft with the rear tires on the ground if you are in 4wd, you just won't be able to turn the jacked up front tire...

[Fropleyqk]

If youve seen a sudden drop in MPG take a look at the basics: air filter, plugs, the 97's have distributors right? Check the plug wires, o2 sensors tire pressure. Good luck and isnt it an awesome feeling when you think something big is broke then everyone chimes in and tells you its normal? Like a huge weight being magically lifted.

[BlueFlame]

Originally Posted by dzride

Like been mentioned before the drivesaft will always spins. You need turn off engine,jack up front wheel and put in gear if wheel will spin in 2wd you're fine.

We are saying the exact same thing.

When you spin the tire the driveshaft will only spin if you're in 2wd.
(If you were in 4wd it would be locked to the rear shaft, so you'd have to turn the rear driveshaft too...)

[Fropleyqk]

Originally Posted by BlueFlame

We are saying the exact same thing.

I saw that too. I was going to make a witty comment there but I didnt...

[dzride]

Originally Posted by NotURMailman

Blue Flame's point it that you won't be able to turn the front drive shaft with the rear tires on the ground if you are in 4wd, you just won't be able to turn the jacked up front tire...

He is afraid that he is stuck in 4wd and if he'll turn his tire in 2wd, that means he is fine.

[NotURMailman]

Originally Posted by dzride

He is afraid that he is stuck in 4wd and if he'll turn his tire in 2wd, that means he is fine.

Umm... yeah... that's what I just said... it must be your day to repeat what everyone else said using different wording!

[dzride]

Originally Posted by BlueFlame

We are saying the exact same thing.

When you spin the tire the driveshaft will only spin if you're in 2wd.
(If you were in 4wd it would be locked to the rear shaft, so you'd have to turn the rear driveshaft too...)

Sorry Misunderstood