New guy with a transfer case question.

[bob72gts]

So before I get flamed for not searching before asking this question, let me say that I did search but did not find what I was looking for. Anyway here's the deal.

A friend of mine has a 97 Mountaineer and it is eating it's front differential. She really does not have the money to fix it properly, so I am looking into turning it into a 2wd just to get her back on the road. Removing the front diff, driveshaft and cv's is pretty straight forward. I plan to remove the outer joint cups from the cv shafts and reinstall them in the front hubs just in case they are required to hold the hub and bearing together as I have seen on some front wheel drive cars.

Now for my question.....

Can anyone on here tell me whether or not the Tcase is going to freak out? If there is going to be an issue with the AWD Tcase trying to drive the front wheels and therefore not driving the rear ones or the possibilty af excessive slipping then I will let her know we can't do it that way. I suppose I could pull the front shaft and drive it around the block, but I was hoping someone could save me the time.

Thanks

 

[sean99]

Info about ex creeping in park: http://www.explorerforum.com/forums/showthread.php?t=275074&highlight=creeps+in+park

 

[bob72gts]

Thanks for the quick reply on that. If the worst problem she has is having to set the parking brake every time she parks, that will be great. I will get the shaft out and drive it around. If it drives normally then she will be 2wd tomorrow. Might even get better mileage.

 

[ragajungle]

Info about ex creeping in park: http://www.explorerforum.com/forums/showthread.php?t=275074&highlight=creeps+in+park

^^^ you mean the thread that is a fight about 4wd vs awd stereo bezzels? LOL

 

[BrooklynBay]

Welcome to this forum! I've moved your thread into the transmissions & transfer cases section.

 

[sean99]

^^^ you mean the thread that is a fight about 4wd vs awd stereo bezzels? LOL

post #4

The reason why your truck rolls when on an incline is directly related to the fact that you do not have the front driveshaft installed. The way that the transfercase is set up in an All Wheel Drive truck is different than that in the Auto-4 wheel drive truck.
IF you had the 4 wheel drive truck, that switch would control an electronic clutch in the tranfercase to engage the front driveshaft. The All Wheel Drive transfercase does not have that electronic clutch, but what it does have is a viscous coupler. This coupler sits between the input shaft from the transmission and the rear output shaft. Wrapped around the outside of that coupler is a chain, this chain drives the front output shaft. This viscous coupler will slip a little bit to allow the front and rear driveshafts to turn at slightly different speeds (such as when cornering). Now, if you have that picture in your mind, the transmissions parking pawl is holding 1/2 of the coupling at a stop (the input shaft only) but since the front driveshaft is not there, the weight of the vehicle will cause the coupling to slip, resulting in the truck rolling downhill. Until you replace the front driveshaft, set your emergency brake every time you exit the truck.
Believe it or not there is some good news, this shows that your viscous coupler is in good working order.

 

[PopRichie77]

Removing the front drive shaft won't stop the front diff from turning, the problem will still be there. The front axles will still turn the diff and any bad gears will still make noise.
if your removing the shaft to check the T/C operation then go for it.

 

[PopRichie77]

If your going to the trouble of removing everything, why not replace the front diff? U pull it salvage yards only charge around 50 to 60 bucks for a front diff. in my area. It's a lot more work for you and you have to find one.

 

[bob72gts]

I pulled the front shaft and took it around the block looks like it will work for now. The gear noise has diminished, but is still there. The damage seems to be mostly on the back side of the gearset, more noise on decel, but now with the shaft out there is no load on ring and pinion. Drained a little fluid out of the front diff, it was really pretty. Lots of metal flake in otherwise clean fluid. This should get her through until 2011. Going to do some pricing at the local yards, I just can't get to it until after xmas. Freebies have to wait.

Thanks

 

[imp]

post #4

The reason why your truck rolls when on an incline is directly related to the fact that you do not have the front driveshaft installed. The way that the transfercase is set up in an All Wheel Drive truck is different than that in the Auto-4 wheel drive truck.
IF you had the 4 wheel drive truck, that switch would control an electronic clutch in the tranfercase to engage the front driveshaft. The All Wheel Drive transfercase does not have that electronic clutch, but what it does have is a viscous coupler. This coupler sits between the input shaft from the transmission and the rear output shaft. Wrapped around the outside of that coupler is a chain, this chain drives the front output shaft. This viscous coupler will slip a little bit to allow the front and rear driveshafts to turn at slightly different speeds (such as when cornering). Now, if you have that picture in your mind, the transmissions parking pawl is holding 1/2 of the coupling at a stop (the input shaft only) but since the front driveshaft is not there, the weight of the vehicle will cause the coupling to slip, resulting in the truck rolling downhill. Until you replace the front driveshaft, set your emergency brake every time you exit the truck.
Believe it or not there is some good news, this shows that your viscous coupler is in good working order.

What you are saying here is that with AWD there is NO MECHANICAL LOCKUP of the rear driveshaft to the transmission output shaft.

Hard to believe, for me anyway, hard to imagine that viscous clutch performs the duty of keeping a vehicle from rolling while in Park.

So hard to imagine, actually, that I will go further out on the proverbial "limb" than usual, and state, I think you are WRONG. imp

 

[sean99]

Hasn't happened to me...Some people have this issue when removing the front driveshaft...
That was a post from my pos mounty. What do you think the real issue is for rolling in park?
What do you think is RIGHT??

http://www.explorerforum.com/forums/showthread.php?t=215726

http://www.explorerforum.com/forums/showthread.php?t=242975&highlight=creeps+in+park

 

[imp]

sean, the links seem to confirm that I am wrong. Anyhow, here's how I'm seeing this thing:

The viscous clutch MUST have an INPUT shaft and an OUTPUT shaft, would that be right so far?

Now if the drive chain powering the front driveshaft were mechanically coupled to the Transfer Case Rear Wheel Output Shaft, the result would be that NO differential action between front and rear axles could take place, as they would be mechanically linked as in the traditional "Four-Wheel Drive". If this were the case, the Viscous Clutch having it's OUTPUT connected to this front-rear couple-up, then the only differential action which could occur would be between the transmission, and the Viscous Output Shaft; this condition would be USELESS.

Where am I missing the boat here? imp

 

[sean99]

What?? Thats more thinking than i can do in a month!!
I was simply relaying the missing driveshaft issue others were having...