need help w/ 4405 transfer case diagnosis

[klund]

Hi all,

First time poster - let me just say this forum has been a great source of info for me since I found out about it a few weeks ago. Anyway I have now come to a point where I am lost on what to do about my transfer case and need some help on what to look for next.

What I have:
97 sport SOHC
Borg Warner 4405-08 transfer case

Symptoms:
A few weeks ago I got stuck on an easy 4x4 trail up in the colorado mtns. Later that day I turned my 4wd on dry pavement and couldn't feel any power transfer to the front wheels (you know that great feeling of the front axel getting power under your feet). On corners (still dry pavement) I could feel binding/shudder and a slight whine sound.

What I've tried so far:
- Lifted the truck on jackstands and put the truck in 4-wheel. The front wheels turned but I was able to stop them with my hands.
- TC fluid is fine. Haven't checked the front diff yet.
- Checked the electric shift motor - it's working fine
- After reading the brown wire mod thread, I tested the torque-on-demand relay - it's working fine as well. I hotwired the brown wire and verified that I get the same symptoms described above.

At this point I am thinking the clutch in the transfer case is bad. Does this mean I have to replace the whole case?

Any other ideas of things to check?

Also, what is causing the binding/shudder/whine on corners when the 4wd is turned on? I assume it's the front diff - does that mean there is some sort of electronic engagement mechanism for the front diff? or could that actually be from the TC?

Thanks,
Kraig

 

[IZwack]

Hey Kraig whats going on

When you put all of the tires in the air and stopped a wheel with your hand, did you stop both wheels with you hand? Because if you stop only one, the differntial will allow the other one to still turn -- so that the front output shaft o the transfer case is still rotating. But actually I wouldn't dare stop both front wheels while its up in the air That just sounds like it might swallow me whole - or break your wrist

The front differential is open and there is no "locking" mechanism between the two axle shafts.

The fact that you're still getting binding around turns indicates that the clutch pack is still working fine.

On the next rainy day, place your vehicle on a moderately steep hill covered in grass. Place the vehicle so that the front is pointing down hill. Then put the vehicle in 4HI and the transmission in Reverse and see if the front wheels are able to spin on the grass - kinda like a burnout I guess but dont do it too long - just a quick short burst (have a passenger watch the passenger tires). I'm 90% sure you'll be able to spin your front wheels cauz you're able to get binding around turns on dry pavement.

 

[klund]

Hmmm, no I actually only stopped one wheel and didn't think about the other wheel (and I really used my shoe not my hands and was very careful while doing so). But still, I can't feel any power under my feet while driving but I am pretty sure the tc clutch is getting electric power...

 

[IZwack]

But still, I can't feel any power under my feet while driving but I am pretty sure the tc clutch is getting electric power...

Yeah I'm pretty sure the clutch is getting power too cauz ur getting bind on dry pavement.

Of course you'll only feel power under your feet if there's traction
If theres little or no weight on one front tire, consider it a 2wd vehicle even tho its on 4WD

 

[klund]

IZwack,

OK I think I understand what your saying. The binding is due to the speed difference between the front and back wheels - not driver vs. passenger wheels (Im a total noob to this stuff it you couldn't tell already ). So that would make sense that the TC is engaging.

I'll try your suggestion about the grass hill on a rainy day - actually it will probably be more like a dirt hill on a dry day since we don't get many rainy days here in CO

I still think there is something wrong with the TC though - just not sure what... I'm so confused

 

[IZwack]

OK I think I understand what your saying. The binding is due to the speed difference between the front and back wheels - not driver vs. passenger wheels . So that would make sense that the TC is engaging.

Yeah you got it -- as long as you understand the concepts, then you should be able to figure this out. In the end, its all about the basic concepts - everything just flows after that

 

[gijoecam]

Simple way to check it. Jack the front end up, start the engine, and switch to 4high. Then, crawl underneath the truck, and put a big honkin' pair of channel locks on the front driveshaft and try to turn it. If you cannot turn it, there's a pretty good chance that the transfer case isn't the problem.

Assuming it won't turn, wedge a brick or rock underneath one of the tires and try to manually turn the other wheel. If you can hold one stationary while the other one spins, there's an axle problem.... halfshaft, axle shaft, or diff spider gear issues come to mind.

Now, if the front driveshaft turns when you wrench on it, you have a transfer case issue. Check for power at the brown wire with a 12V test light or DMM. If you've got power at the brown wire, but no lock-up, disconnect the transfer case wiring at the connector, and check for continuity to ground through the transfer case clutch coil. If you've got a ground, the clutch isn't failing electrically, it's a mechanical issue.

If it's a mechanical issue, let us know and IZWack will be along shortly to get you going on the tear-down and replacement process.

Good luck!

-Joe

 

[klund]

Cool, thanks for your help guys. I'll let you know what I find out after I try the suggestions.