I bought a 96 f150 5.8 v8 4x4 eddie bauer edition this summer and have been tinkering with it every financial chance I get. Now that we are finally into winter here in Colorado I have noticed a very uncomfortable shaking when the truck is in 4 wheel drive. I have pretty much narrowed it down to a bearing in the transfer case and was wondering if anyone knew where I could find a decent remanufactured or used t-case. Or if you have any ideas as to what else could be causing this. the transmission is e40d and i believe the transfer case is warner 1356 electronic. Thanks in advance and I look forward to learning more about our trucks everyday.

 

Only in 4x4 right? Any play in the front u-joints?

 

Correct, and I haven't noticed anything out of the ordinary, it is only really truly noticeable at higher speeds, about 60 or so you can really start to feel/hear it, but if you pay close attention it can be heard above 40.

 

If the roads are clear enough to be doing 60, you don't need to be in 4wd.

I'd be more inclined to think this vibration is caused by something in the front driveline: axle u-joints, driveshaft u-joints, bent driveshaft...

 

+1, what he said. Not much in the transfer case that causes a vibration when bad only in 4 wheel drive. What I would do is remove the front driveshaft and take it for a ride in 4 wheel drive. Make sure both hubs are unlocked. Bet you won't get the vibration then, but if you do and it's only in 4Hi we can look at the transfer case. If you don't get the vibration, then we know it's in the front driveshaft or axle(s) so we'll check the axle next.

Next step is leave the front ds out and drive it with the hubs locked... if it vibrates then it's in the front axles. No vibration, it's the front driveshaft.

If you have auto hubs you'll have to reinstall the front shaft to get the stupid hubs to lock in for the second part of the test. Or do what I said in reverse order.

 

Sounds like my truck when I had a driveshaft U joint going bad.

 

4WD gets used so infrequently on most of these trucks it's FAR more common for the front drive U-joints to dry out and seize, so looking for loose joints is a complete waste of time and it's is extremely uncommon for the T-case to have any issues... ever. The drive axles have to be removed from the vehicle to change the u-joints .. which is a pretty big job but if you replace them all with greasable versions it's quite possible you'll never have to do it again.

 

Thanks guys, looks like I'll be replacing u-joints to start with this weekend and see where that gets me.

 

I agree. Even my 08' says not to go over 50 or 55 mph in 4 wheel drive in the owners manual. The only vehicle that doesn't state a max speed is my wife's Jeep Patriot. Apparently you can drive 100 mph in 4 wheel drive in that thing.

 

why do the drive axles have to come out to change the u joints in the shaft??

 

Because there is no room to get the caps of to change the joints...

 

ok ,I misunderstood, i thought they were talking about the drive shaft,not the axle shafts.

sorry ken

 

they are talking about the axle shaft u joints having to remove the axles. the front drive shaft u joints just the shaft has to be taken out.

 

ok,thanks , my bad

ken

 

I have a write-up that will take you all the way up to the front axle u-joints, if you need it look for the Front End Rebuild link in my signature. Also, since you want to check the T-case, I would just recommend an ATF replacement, there are two drain plugs on the rear cap of the case, the top one is actually a filling plug, take the lower one off to remove all the old fluid, then seal it back and fill it with 2 qts. of fresh ATF, or until you reach the filling plug.