Broken Transfer Case Coupler! - Diesel Forum

tool_41 · 01-02-2008, 04:43 PM

A friend of mine has a '99 F250 Extended Cab, 4x4 (Electric shift with Manual Hubs) auto tranny, 5.4 Gasser.

She has been complaining about noise and vibration when driving and then just the other day a "Clunking" under accleration.

So I crawled under it the other day to discover that the cast iron section between the tranny and they transfer case is busted!

I'm not 100% sure what this part is, I only had a quick look and obviously saw what the porblem was in about 30 seconds, I think it is a coupler of sorts between the tail shaft of the auto tranny and the input shaft of the transfer case. Not sure if this is actually a part of either the tranny or
t-case.

She is a young single girl on a tight budget, 2500 miles from her family so it looks like I will be fixing it for her in my garage. I'm not a 4x4 guru by any stretch but I did replace the Manual Tranny and t-case in my '99 Dodge last year and it doesn't look that tough to get apart, (besides all the corrosion!)

Does anybody have any experience with these trucks or know anything about it??? I had a quick look in a Haynes manual but it didn't seem to show where the tranny and t-case splits or really have much usefull info at all, the Haynes for my '99 Dodge is much better.

Any help would be appreciated.

Thank you.

klhansen · 01-02-2008, 04:50 PM

The extension housing bolts to both the tranny and t-case, so you should be able to unbolt and replace just the extension housing. However, you might want to closely inspect the tranny and t-case for other damage. Something caused the extension housing to break, and you'll want to fix that also.

tool_41 · 01-02-2008, 05:02 PM

Yes definitely.

I'm suspecting possibly a binding slip joint or a piled up T-Case....

By the look of the extension housing something would have to torque it pretty good to break it.

Anybody ever heard of that part breaking before.

Are theyre any moving parts in the extesion housing or is it just the tranny output shafy running to the t-case?

klhansen · 01-03-2008, 02:30 AM

Usually it takes being "tapped" in the rear or front end driving the driveshaft to the limit of the slip joint to break the extension housing like that.

The output shaft of the tranny is connected to the input shaft of the t-case with a splined sleeve. Not much to go wrong there, but an output or input shaft bearing could be damaged. Once you have it apart, turn the shafts by hand, checking for bearing roughness or wobble (bent shaft).

tool_41 · 01-03-2008, 08:32 PM

OK, thank you. I will definitely do that.

Any sure tests to put the tranny or t-case through while I have it apart to check stuff before I put it back together???