Transfer case. Good or bad?

[rasouth]

I have a '96 4-wheel drive Exploder that has developed a buzzing or whining noise when coasting. At first I thought possible transmission problems but have been pushed towards possible transfer case problems. After Exploder has been driven and warmed up a whining/buzzing noise comes from the TC/trans area when I start to coast down hill. The noise will go away when I press on gas pedal or slow down below 30mph. I have read other posts that have similar problems and that is how I was pushed towards transfer case. Not sure if I want to rebuild or get another one from salvage yard. My question is...Is there a way to tell a good from a bad transfer case if I bought one from a salvage yard?
I have tried flushing mine and got nothing but black sludge from it. It looked like runny peanut butter. I ran several bottles of old ATF through it to flush out as much sludge as I could and then filled with clean ATF. I plan on running it for a while and then flush again, but as of now I still have same problem.

 

[XLTrunner]

Are you able to shift in and out of 4-wheel drive? If you had that much sludge inside the t-case, you might want to remove and clean the ends of the Halls Effect Sensors. I can guarantee they are coated with it, too.

I went thru a t-case rebuild last summer and, like you, first considered a used one from the local Pick-n-Pull. But, I didn't know of any way to determine whether it would be usable, either. In the end, I took my truck to the local tranny shop who rebuilt it for around $800. Here is an older thread that is a great tutorial as to how the 4405 Borg Warner works and can be disassembled/rebuilt.

http://www.explorerforum.com/forums/showthread.php?t=182071

Lastly...you're sure the noise isn't coming from the rear diff?

 

[rasouth]

I'm pretty sure that the noise is not coming from rear diff. Everybody that has heard the noise agree that the noise is coming from the middle section of car, not the rear.
I don't believe that the 4-wheel drive is effected. Once, when the noise first appeared, I pulled over and stopped the car. When I tried to shift into drive or reverse I got the buzzing/ grinding noise, as if it was not engaging. I tried the 4-wheel drive switch and still got the noise. After a few minutes I was able to engage drive and drove home with no problem except the noise would reappear when coasting downhill.

 

[drdoom]

It is either the t case or mismatched tires.

 

[drdoom]

If it is the t case eventually you will lose engagement altogether and you won't even be able to shift into park without cutting the engine off. You will have 4low though to get yourself off the road.

 

[rasouth]

It's not the tires. They are fairly new and the same size.

 

[drdoom]

Well the best thing is to rebuild it then. Make sure to have the case halves sleeved and use the fork upgrade.

 

[rasouth]

Thanks for the input and information. I have found a couple of used t-cases listed at local salvage yards or online but I have no idea if they are good or not. Don't know if I want to gamble on a $200 t case versus an $800 rebuild.

 

[XLTrunner]

Therein lies the dilemma I was faced with. I would encourage you to discuss the cost to rebuild it with your repair shop before making the decision. It may well be substantially more than $800.

At the time, I also researched purchasing a rebuilt unit from Midwest Transmission Center (who's within an hour's drive of me) and it was going to cost around $900 (after core charge deduction) by the time I paid 7% sales tax and gas to run down and pick it up...and, I'd still have to remove and install myself; which I wasn't totally comfortable with laying on my back in my driveway trying to maneuver that heavy thing in and out of the truck. Seems I also recall the two upper mtg bolts are extremely difficult to access without lowering the transmission or cutting an access hole in the truck's floor? For me, this was just one of those times when I felt it's worth paying somebody to do the work. And, as it turned out, ended up being cheaper than buying a rebuilt unit and installing it myself.

Good luck with it.

 

[kevinspann]

I've got to pull my transfer case as well...

Has any one else had issues getting the rear driveshaft to T/C flange bolts out? I have the parking brake set, and am putting enough torque on the bolts to over power that. Granted, the parking brake has never been strong enough to hold the Explorer on an incline, but I don't feel like the bolts should be that hard to get out.