2000 Mountaineer - Whine on acceleration - Quiet as a mouse on deceler

[imp]

The front of the 2nd gen transfer cases does have a good seal, and the short trans tail housing will let excess fluid into that space. But an overfill from the trans would have to fill that short housing quite a bit to produce fluid at the TC front seal. I think the seal will stop virtually all fluid come getting in. The trans would have to be very overfilled to put enough at the TC to get any in. The trans overflow vent would be well used before anything got into the TC. It's pretty bad to overfill a trans that much, I doubt that happened but didn't hurt the trans enough that it all got taken apart.

I'll bet trans hasn't been hurt, and the AWD TC is like all others, bad fluid suggests it had bad tires on it. The question is how long was the truck run with mismatched tires. I got my 98 with 158k on it, and black TC fluid. I changed it then, and about five months later, still black, and about nine months later, still black.

At around 198k last year, I began to feel a binding in the front while turning. I didn't immediately conclude it was a bad TC. I had new front control arms to put on, and saw a barely torn CV axle a week before. So I replaced the axle and inspected, nothing to see. I got two days off and did the four CA's, driving to the alignment it had major popping backing out and driving straight. Then I decided it was the front diff, I was right, came home from the alignment and swapped a used one in. That "fixed" the bad popping, the old diff/pinion could move a bunch side to side. The binding also was not gone, so after a bit of driving to test, I removed the front driveshaft. Bingo, symptoms gone, the AWD TC had basically locked up and took out the front diff. I've driven it that way since then, gladly the TC is still transferring power. I've read that sometimes when the AWD fails, there's no movement.

@CDW6212R
So the front diff could not take the rigors of getting 4WD action all the time on pavement! And the TC kept showing up black, like clutch overheat. By "no movement", you mean the vehicle won't move? Did you once again change the TC fluid? Amazing story, thanks for it! imp

 

[pjfsail]

Whine on acceleration is most likely bad carrier bearings, and noise created between gears when separated from torque.
The trans has a drain in the tail housing, allowing fluids into the transfer case. I have to plug that drain after the tcase is removed, when I pull the trans, so it doesn't make a mess. Beats having to work around a drain pan.

gmanpaint, The oil had to have come from somewhere and this sounds like the answer. I would guess from service records I received from the previous owner, the transfer case oil probably had never been changed in 200,000 miles. If this leakage is small over a period of time it would naturally build where the transfer case would be overfilled. So, I wonder now, (always questioning!) what affect the overfilled transfer case would have on the whining noise? I'll be finding out soon when I refill and road test. It's cold here on the High Desert and my shop is outside. waiting for a warm day.

 

[gmanpaint]

Sorry, I left out the part I meant to include about the fluids from the trans.

The front 4404 input seal would have to be bad, to allow the flooded tail shaft housing, to drain into the 4404 case.
(Picture borrowed from Gavin's rebuild thread)

The cavity you see in front of the seal holds trans fluids to lube the tail shaft as it spins. However, the tail housing is not meant to be filled completely, just partially, as it recirculates the fluids back there.

The seals on these do indeed fail now & then, but the rear output seal is more common.

These cases could hold a lot of fluids if filled, and if the previous owner noticed low trans fluids, and kept adding a little at a time, it could explain this somewhat.

Does the case look wet & dirty like the case in the picture above? If the case had a bad rear seal, or a bad case to trans seal, that would happen.

If the case is dirty above, that's from the vent tube. The vent is mainly for hot gas, but if the case was overfilled, and boiled over (black in color) it would have jettison out of this tube.


As I mentioned earlier, your whine on acceleration only, is from rear diff carrier bearings. If you had a bad vibration/clunk noise with it, I would say U-joints and/or Pinion bearing, but I don't recall you mentioning a vibration.

 

[CDW6212R]

The AWD transfer case is basically not heard or felt, even when something's wrong with it. It's basically like a very large open differential with a tiny torque converter powering the front drive. There is a chain and a chain guide, small planetary, and several bearings. Sure if it has a catastrophic failure of chain or main bearings etc, then there will be damage that stops movement for sure.

But the viscous clutch is by far its weakest link, and that is a self contained part that basically creates heat when the front driveshaft spins at a different speed then the rear driveshaft. It has it's own internal fluid but I think when it begins to be hurt, some comes out and shows as black in the main TC fluid.

So your whine is still very likely from the diff, ring/pinion/bearings. If the fluid there is old(which is biggest cause of damaged bearings etc), then get into it soon and carefully inspect the ring gear, pinion too, and see if they are still okay. Even with noise, if the ring and pinion are decent, they can still survive for many years(with fresh bearings and grease).

 

[CDW6212R]

@CDW6212R
So the front diff could not take the rigors of getting 4WD action all the time on pavement! And the TC kept showing up black, like clutch overheat. By "no movement", you mean the vehicle won't move? Did you once again change the TC fluid? Amazing story, thanks for it! imp

My truck never stopped moving, the fluid was just always black since I got it and changed it four times over two years. The possibility of an AWD Explorer not moving at all is from a couple of posts by members here. Those were not big members, but I take those posts as decent proof that it is possible for the AWD TC to fail to transmit any power. I think those cases were likely from bad tires and no fluid changes, plus the people kept driving until it stopped moving.

 

[pjfsail]

Sorry, I left out the part I meant to include about the fluids from the trans.

The front 4404 input seal would have to be bad, to allow the flooded tail shaft housing, to drain into the 4404 case.
(Picture borrowed from Gavin's rebuild thread)

View attachment 166293

The cavity you see in front of the seal holds trans fluids to lube the tail shaft as it spins. However, the tail housing is not meant to be filled completely, just partially, as it recirculates the fluids back there.

The seals on these do indeed fail now & then, but the rear output seal is more common.

These cases could hold a lot of fluids if filled, and if the previous owner noticed low trans fluids, and kept adding a little at a time, it could explain this somewhat.

Does the case look wet & dirty like the case in the picture above? If the case had a bad rear seal, or a bad case to trans seal, that would happen.

If the case is dirty above, that's from the vent tube. The vent is mainly for hot gas, but if the case was overfilled, and boiled over (black in color) it would have jettison out of this tube.


Oh..... As I mentioned earlier, your whine on acceleration only, is from rear diff carrier bearings. If you had a bad vibration/clunk noise with it, I would say U-joints and/or Pinion bearing, but I don't recall you mentioning a vibration.

What an education on transfer case function, thanks. No, I don't recall a vibration only the whine and there was not any clunking. I just went out and looked at the transfer case to see if it was dirty/oily as I remember it being clean and it is. There is no sign of oil on the transfer case.

 

[pjfsail]

The AWD transfer case is basically not heard or felt, even when something's wrong with it. It's basically like a very large open differential with a tiny torque converter powering the front drive. There is a chain and a chain guide, small planetary, and several bearings. Sure if it has a catastrophic failure of chain or main bearings etc, then there will be damage that stops movement for sure.

But the viscous clutch is by far its weakest link, and that is a self contained part that basically creates heat when the front driveshaft spins at a different speed then the rear driveshaft. It has it's own internal fluid but I think when it begins to be hurt, some comes out and shows as black in the main TC fluid.

So your whine is still very likely from the diff, ring/pinion/bearings. If the fluid there is old(which is biggest cause of damaged bearings etc), then get into it soon and carefully inspect the ring gear, pinion too, and see if they are still okay. Even with noise, if the ring and pinion are decent, they can still survive for many years(with fresh bearings and grease).

This is good news, when I looked at the ring gear and pinion when I had the rear cover off, from what I could see both looked good. Without putting a dial indicator on to check backlash I would say it was OK too.

 

[GLOCKer]

This is good news, when I looked at the ring gear and pinion when I had the rear cover off, from what I could see both looked good. Without putting a dial indicator on to check backlash I would say it was OK too.

Yeah, I'm still going with your bearings being toast. I had the same exact symptoms and found my pinion bearings shot.

 

[pjfsail]

Yeah, I'm still going with your bearings being toast. I had the same exact symptoms and found my pinion bearings shot.

I'll bet you are right. I have my work cut out for me. For right now I am going to replenish the oil in the transfer case and the differential with oils so I can drive it. It is a second vehicle so I wont drive it much but because my shop in outdoors I won't be able to do much until spring. I WOULD LIKE TO THANK EVERYONE ON THE FORUM FOR THEIR INPUT. I HAVE LEARNED SO MUCH ABOUT TRANSFER CASES AND SYNTHETIC GEAR OIL. I FEEL INFORMED. THANKS!

 

[CDW6212R]

I'll bet you are right. I have my work cut out for me. For right now I am going to replenish the oil in the transfer case and the differential with oils so I can drive it. It is a second vehicle so I wont drive it much but because my shop in outdoors I won't be able to do much until spring. I WOULD LIKE TO THANK EVERYONE ON THE FORUM FOR THEIR INPUT. I HAVE LEARNED SO MUCH ABOUT TRANSFER CASES AND SYNTHETIC GEAR OIL. I FEEL INFORMED. THANKS!

If you drain the rear diff, again after a short time, the gear oil should be relatively clean. If you find any material in it really, then there is some fast wear happening. If it is, I'd hope that it's the axle bearings, and change them now(plus seals). The main carrier bearings are the strongest, and axle bearing wear usually is the start of damage, wearing the axles and then it affects the main bearings, lastly the ring/pinion gears.

 

[pjfsail]

If you drain the rear diff, again after a short time, the gear oil should be relatively clean. If you find any material in it really, then there is some fast wear happening. If it is, I'd hope that it's the axle bearings, and change them now(plus seals). The main carrier bearings are the strongest, and axle bearing wear usually is the start of damage, wearing the axles and then it affects the main bearings, lastly the ring/pinion gears.

I have 75w 140W Gear oil and Ford's modifer. I think I'll do as you suggested and fill it run it for a few and drain it out having a good look at any material that might be in it. (There was no metal other than brass in the original drain of the differential.) Then from Carquest I bought 3 quarts of Royale, Purplel 75w 140w gear oil, it's expensive but in the overall scheme of things, not so much. Of all the reviews of gear oil I read this seems to be by far the best.

 

[donalds]

Ams oil is the best by farrrrr

 

[pjfsail]

Ams oil is the best by farrrrr

Thanks, I already paid for the 3 bottles of Royal Purple so I'll have to such it up and go for #2. I use Ams for my motor home, engine oil, primary filter, secondary filter, transmission fluid and never thought about their gear oil being the best too.

 

[donalds]

Thanks, I already paid for the 3 bottles of Royal Purple so I'll have to such it up and go for #2. I use Ams for my motor home, engine oil, primary filter, secondary filter, transmission fluid and never thought about their gear oil being the best too.

He'll yea yeeyeee

 

[CDW6212R]

I have 75w 140W Gear oil and Ford's modifer. I think I'll do as you suggested and fill it run it for a few and drain it out having a good look at any material that might be in it. (There was no metal other than brass in the original drain of the differential.) Then from Carquest I bought 3 quarts of Royale, Purplel 75w 140w gear oil, it's expensive but in the overall scheme of things, not so much. Of all the reviews of gear oil I read this seems to be by far the best.

That sounds good, it's not hard at all to R&R the pan and gear oil. Get a hand oil pump made for quarts, that makes filling much easier. I hope it doesn't shows any more material the next time, but replacing the axle bearings and seals is not that bad, if the cross pin bolt loosens without breaking.

I use Amsoil also, their Severe Gear is excellent, though it's gone up a dollar or so($14ish for the 75W-140).

 

[gmanpaint]

I like to run a magnet in the housing valley, so cover has to come off for that. I also use a good Lube Locker diff gasket because I change fluids and inspect a couple times (or more) a year.

Had no Idea AmSoil gear oil was that cheap Don. Mobil1 is like $18. Heck the cheap Super Tech generic synthetic is like $12-$13! As much as I change fluids, looks like AmSoil is going to be my new go go gear juice.

 

[CDW6212R]

It used to be $11-$13, for the three viscosity's. Last year they began having free shipping days, and then made it free over $100. In the Fall I noticed the prices had gone up a little on most all fluids I buy, and I got some more Severe Gear too. i usually have 3-4 quarts of the 110 and 140 weights, I might use the 90 in the front of a stock truck in light usage.

The six or 12 month subscription is worth it if you buy several of their fluids regularly. I like their basic synthetic oil better than other brands, it was $5 a quart, I think it's close to $5.50 now. They made it hard to choose ATF though, they used to only have one, now they make several versions.

 

[gmanpaint]

So if you don't have a local dealer, you get a company subscription, order it online, and have it shipped for an extra charge?
That brings the price up on it that way.

I have seen few local dealer tucks driving around me, so I think I could call, place an order, than just go pick up. I have yet to run AmSoil, and never had to deal with the red tape getting it.

Sorry for the thread hi-jack!!

 

[CDW6212R]

So if you don't have a local dealer, you get a company subscription, order it online, and have it shipped for an extra charge?
That brings the price up on it that way.

I have seen few local dealer tucks driving around me, so I think I could call, place an order, than just go pick up. I have yet to run AmSoil, and never had to deal with the red tape getting it.

Sorry for the thread hi-jack!!

No it isn't that expensive, the member subscription is $16 for a year, I do that automatically. The only real costs are the taxes or shipping depending on how much you spend, or if in a zone where they charge sales tax(which is in most places I think). I don't have the luxury of any local sources, though most items are drop shipped by someone closer than their main location. The big savings is to get enough to have free shipping, or buy during the odd free shipping day they tell you about by email.

Edit, the Severe Gear 75W-140 is now $15.30 each, I didn't remember how much it went up in the Fall. Buying 12 makes it just about $14.56 each($174.70)

 

[pjfsail]

I like to run a magnet in the housing valley, so cover has to come off for that. I also use a good Lube Locker diff gasket because I change fluids and inspect a couple times (or more) a year.

Had no Idea AmSoil gear oil was that cheap Don. Mobil1 is like $18. Heck the cheap Super Tech generic synthetic is like $12-$13! As much as I change fluids, looks like AmSoil is going to be my new go go gear juice.

I paid $22.00 + for Royal Purple.