why...
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TractorLegend
Platinum Member
Im not quite yet sure of the science but here was my experience about their friction modified 90W-140 Motorcraft diff lube. I had a 2000 Ford Explorer since new. I thought I'd drain the factory fill at about 3K and use another brand Mobil 1 synthetic lube. So I did. After a few miles the truck shuddered from the posi. plates in the rear, on corners. No issue before.
I added friction modifier. Still had issue. I drained it all and added Fords lube. Still had trouble. Dealer replaced clutch plates in rear diff under warranty. I have seen synthetic work in bigger Ford diffs like the superduty, but the smaller ones will give issue now and then. Safer to use factory, in this instance.
I also would only use Chryslers friction modified fluid in their late model overdrive trannys as opposed to regular Dexron and Lubegard or other supplements along with. You may end up with torque converter shudder at about 38-42 mph. It happened more than once to me and all that happened was a waste of 35.00 worth of materials and labor to swap it out.
Others will likely differ since this is the "Oils" forum. /forums/images/graemlins/ooo.gif
But this advice comes free
I added friction modifier. Still had issue. I drained it all and added Fords lube. Still had trouble. Dealer replaced clutch plates in rear diff under warranty. I have seen synthetic work in bigger Ford diffs like the superduty, but the smaller ones will give issue now and then. Safer to use factory, in this instance.
I also would only use Chryslers friction modified fluid in their late model overdrive trannys as opposed to regular Dexron and Lubegard or other supplements along with. You may end up with torque converter shudder at about 38-42 mph. It happened more than once to me and all that happened was a waste of 35.00 worth of materials and labor to swap it out.
Others will likely differ since this is the "Oils" forum. /forums/images/graemlins/ooo.gif
But this advice comes free
When I had my F350 Powerstroke, I added the 8 qts of Amsoil Series 2000 and a Magtech Diff cover.
No problems with anything in 80K+ miles!
When I pulled off the rear cover and saw the brown liguid (smelly too), no way that is staying in there.
But my BX has Amsoil in the diff! /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif No problems in 1.5 years.
No problems with anything in 80K+ miles!
When I pulled off the rear cover and saw the brown liguid (smelly too), no way that is staying in there.
But my BX has Amsoil in the diff! /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif No problems in 1.5 years.
TractorLegend
Platinum Member
My brothers Powerstroke has that rear cover and he uses Red Lines Shockproof with no issues either.
Interestingly Fords Motorcraft lube is "synthetic" according to bottle. At a whopping 20.00 a quart~
I may look on iATN later when I get time to see if others had issues besides in my neighborhood.
It's a website for professional auto techs I'm a member of and can check postings for specific issues, such as this and others. I know a few "Ford only" techs across the country I can quiery to see whats the deal on Ford's posi rear end lube.
Interestingly Fords Motorcraft lube is "synthetic" according to bottle. At a whopping 20.00 a quart~
I may look on iATN later when I get time to see if others had issues besides in my neighborhood.
It's a website for professional auto techs I'm a member of and can check postings for specific issues, such as this and others. I know a few "Ford only" techs across the country I can quiery to see whats the deal on Ford's posi rear end lube.
Its in my 04 f-150. I was getting some pretty bad chatter until they replaced the clutch pack and installed there fluid and modifier. I do still get a little chatter on straight line take offs.
Im not sure if I should just go ahead and swap it myself or what. The magnet cover looks like a good upgrade as well.
Im not sure if I should just go ahead and swap it myself or what. The magnet cover looks like a good upgrade as well.
JerryG
Super Member
Straight Ford friction modifier smells like rotten eggs.
Donnyj
Platinum Member
We at the dealership call it panther p*ss. /forums/images/graemlins/grin.gif I have found adding a second bottle instead of the called for 1 helps alot. Some of the problems with the clutch packs in the rear was they were installed wrong at the factory. Instead of having a steel and then a friction plate some were installed with steel to steel or friction to friction. A clutch pack problem should show itself when making hard right or left turns, not so much when taking off straight. Really notice when the wheel is turned hard to one side and going around in circles. Newer Explorers are really bad. Alot of rear diff problems. Alot of service messages at the dealership for Explorer and Expedition rear diff problems in newer models. The independent rears seem to be the problem. Explorer Sport Trac uses solid rear end with very little problems. Just some info if anybody was interested.
I know but it does not help the diff oil either. Brown oil is not the best here. For me, why not use a synthetic oil that has these already installed in the oil? For the $64 for the fluid (which last longer then Ford's), it is worth it I feel.
I did feel it alot when turning, that was my biggest complaint, seems cool now. Would I hurt anything if I swapped the fluid myself?
I guess I need torque specs and torque sequences and all that.
Does that mag cover have a dipstick and fill port?
And, does the ford lube have a higher shear stability than the amsoil.
I guess I need torque specs and torque sequences and all that.
Does that mag cover have a dipstick and fill port?
And, does the ford lube have a higher shear stability than the amsoil.