Transfer case rebuild

Don W.

Don W.

Stab it and steer it
Well it seems that I may be dealing with a bad transfer case. Rear tire spin at launch is the clue. Just starting to research this. I've looked at removal, parts kits ect on this thread. So...

First Q: Is there a foolproof way (Besides my rear tire spin at launch:roll: ) to verify that the viscous clutch is, in fact, bad.

Next: Reason for first Q. Cost. Someone said the clutch is costly but how much $$ are we talking about?

Last: Looks like a fairly straightforward job, but any tricks would be appreciated.

TIA
 
gjp

gjp

another post whore
Re: Transfer case rebuild

I always thought it was not worth rebuilding them.??

With that said:
Don I can get you a new one. I know a guy. Never used for 750$.Thats his price. Maybe he would go lower, dont know. Pm me if interested. He is in santa cruz. I would even pick it up for you and you can go to my house to save you time.
 
TYTILIDIE

TYTILIDIE

METH HEAD
Re: Transfer case rebuild

It cost me $280 to rebuild mine(myself ofcourse) and that was about three years ago. Still going strong.
 
gjp

gjp

another post whore
Re: Transfer case rebuild

wow. 280$ Thats it. BTW whats in there? Besides a chain and some trans fluid. I never seen a diagram of one. What goes bad on them?
 
J

'JustDreamin'

Dream: 6LV8 Turbo Bravada
Re: Transfer case rebuild

Here's my best stab at it.

1.) I don't know of an absolutely foolproof way.

It'd be nice to be able to give it a torque test or something kinda like this: Tranny in park, rear tires on the ground, chocked, with parking brake set. Apply xxx torque to front output shaft. If it moves, need new VC.

That'd be the way to do it, but I've never seen a specification for the torque required. Might be huge. Might be speed dependent.


Besides your rear wheelspin, another method is this:
1.) Remove the front propshaft,
2.) Park the truck on a reasonably steep hill, put it in park but don't apply the parking brake
3.) Place a set of chocks about 6 feet downhill of the truck (where they wheels would end up if it drifts).
4.) Leave it alone for a while (8 hours / overnight).
5.) If you find it where you left it, your VC is probably ok. If its on the chocks, it's probably not ok.
Most people do this one by accident not on purpose.


2.) That clutch is Expensive. Like in the $600+ range expensive. The good news is that Sy's and Ty's share the transfer case with the AWD Astro / Safari (up through like '98) and the Olds Bravada (up through like '97) so there are used cases available in salvage yards. (BTW, Later year Astro's and Bravada's use a completely different computer controlled 4x4 case (active-on-demand is what New Venture calls it)).

Sadly, salvage yard units could be just as trashed as your current unit (and no good way to verify it), but sometimes you can get them pretty cheap (like under $100) depending upon the yards you're dealing with, so it might be worth the risk.

Or you can buy a rebuilt tcase with a fresh VC in it, probably for under $1k.


3.) Don't have a Sy or Ty so I can't really help you. I have a '99 Bravada with a swapped in LSX V8. Reason I know any of this is because I wanted AWD and did the research to decide whether to go Viscous Coupling TCase (BW4472 used in Sy / Ty / early Bravadas) or the active on demand case. I decided to run the factory on-demand setup and see how it is. Can't report on it as yet, since I don't have a front diff / driveshaft in place (which the active box will tolerate 100%, the VC box doesn't reall like that).

'JustDreamin'
 
J

'JustDreamin'

Dream: 6LV8 Turbo Bravada
Re: Transfer case rebuild

Foot Performance said:
Any body knoq of a gear driven t-case??
Click to expand...
I'm assuming that you only are thinking of AWD / full time 4x4 cases and not part time cases like the Dana 300 which is popular with the Jeep crowd.

I think one of the early Jeep Quadra-drive (or whatever they called it) was a gear type. Actually had a differential (not sure if it was open or limited slip) in it.

The new TBSS tcase supposedly has a Zexel Torsen type Diff in the tcase to split power front to rear.

I think there were also some Jeep cases that had a differential in the Tcase with a oil pressure limited slip. Basically the two outputs (front and rear) are the two gearsets of an oil pump. Difference in speed creates oil pressure and that applies clutches to get them back to the same speed. I think they were NV247's or something like that.

'JustDreamin'
 
gjp

gjp

another post whore
Re: Transfer case rebuild

I was told the sy and ty use different T cases?? Again I can get a NOS Brand new for 750$. Never even been in a truck.
 
TYTILIDIE

TYTILIDIE

METH HEAD
Re: Transfer case rebuild

gjp said:
wow. 280$ Thats it. BTW whats in there? Besides a chain and some trans fluid. I never seen a diagram of one. What goes bad on them?
Click to expand...

You have the viscous, a spindle, bearings, output shaft, planetary, chain seals. Mine was totally smush when I took it apart. Luckily my viscouse was in good shape cause the cheapest I could find one was $600. A guy here in town gave me one for free and wasnt sure if it worked or not. I juust had to buy the planetary, chain, seals and some bearings. All came in a kit.
 
Don W.

Don W.

Stab it and steer it
Re: Transfer case rebuild

Let me ask this Q: Last winter when I had the front dif out, on re-installation of the front drive-line I could just barely turn it by hand to line up the bolt holes. Is that a clue? Should I have been able to do that, or is that an indication of a loose/bad viscous clutch?

Thanks,
 
4C FED

4C FED

Absolutum Dominium
Re: Transfer case rebuild

I think I remember seeing something in the maint. manual about using a torque wrench on the xfer case output to test for bad viscous.
Something about so many ft. lbs. before the output shaft begins to turn. :dunno:
 
Don W.

Don W.

Stab it and steer it
Re: Transfer case rebuild

4C FED said:
I think I remember seeing something in the maint. manual about using a torque wrench on the xfer case output to test for bad viscous.
Something about so many ft. lbs. before the output shaft begins to turn. :dunno:
Click to expand...

I have the manuals, I'll check.

Thanks.
 
93 TY 2185

93 TY 2185

Donating Member
Re: Transfer case rebuild

4C FED said:
I think I remember seeing something in the maint. manual about using a torque wrench on the xfer case output to test for bad viscous.
Something about so many ft. lbs. before the output shaft begins to turn.
dunno.gif
Click to expand...
This is the only thing I could find in the manual.
 
Last edited:
4C FED

4C FED

Absolutum Dominium
Re: Transfer case rebuild

Ding, ding, ding.....

Go here: http://www.denalitrucks.com/documents.htm

Scroll down to: Member Submitted Files
Then look for: Detailed transfer case info.doc
Download
Then go down to the page with: Viscous Coupling Test

While it's not our transfer case, I'm almost positive there is something like this in our manual as well.
Should work the same I would think.
Drawback: You need special tool to go on torque wrench.:tdown:
 
gjp

gjp

another post whore
Re: Transfer case rebuild

so thats what it looks like in there. good reading.
 
J

'JustDreamin'

Dream: 6LV8 Turbo Bravada
Re: Transfer case rebuild

Well, if you can find a specification, that'd be useful.

There is still the whole "how do you hold the rear output shaft stationary" problem for salvage yard parts, but I guess we should burn 1 bridge at a time.

'JustDreamin'
 
M

Matthew Little

New member
Re: Transfer case rebuild

Just got my parts(viscous, chain and bearings) 412.00 from WIT(what ever it takes). my buddy orders a ton of gn tranny stuff from them and had me call about the transfer case.
I was glad to find this because all the other parts I found were just as much as a rebuilt case. There number is 1-800-940-0197.
 
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