Hey Folks,

Getting my factory LSD replaced with a TrueTrac. Eaton recommends against using synthetic oil, but Ford says to use 75w140 synthetic in the axle. My question is, does Ford recommend the synthetic for protection of the Ring and Pinion or outer bearings? Or is it because of the factory LSD? If I am putting a torsen type unit instead of the factory clutch type, will running Dino 90 weight oil hurt any of the original axle parts?

Okay, that was more than one question... sorry. BUT, I want to choose the best lubricant for the gears and bearings while also getting the most lock-up out of the TrueTrac.

Thank you for any experience with this.

James

 

In my Explorer with Truetracs front/rear, I just used non-synthetic in the same weight Ford recommends. Seems to work. I take it offroad all the time and I get really good traction.

 

Once you put the TruTrack in, it's no longer a Ford diff. The Synthetic oil with friction modifier Ford recommends is for the clutch type diff - which the TruTrack is not. Most bearing, and the R&P, don't care what type of lubrication you use, as long as you use it!

 

Thanks guys!

I have just read posts until my eyes bled about this and there seems to be no real consensus about it. SOME say that if you don't use the Ford synthetic then the bearings will not get lubricated enough and burn up..... that made me nervous. My gut is telling me what you two have said. A ring and pinion and bearings don't care what gear oil is used as long as it is present.

Next question: I tow heavy about 5 times per year (camping), will I have to change out the Dino based oil often because of this? Or is that NOT considered a "heavy towing" situation by Ford?

Thank you again!

James

 

I find that claim virtually impossible to prove. Eaton recommends non-synthetic gear oil for the TruTrack - I don't see how they can recommend that if the bearings weren't already compatible with the oil. Yes there are benefits to synthetic oils under certain circumstances (i.e: a clutch type differential), however, I don't see how using standard gear oil would negatively impact roller bearings in any way.


Nope, they shouldn't care at all. I'm not aware of any R&P being engineered for a specific type of oil.


I wouldn't consider that heavy towing. Since the TruTrack install, my highest temp I've seen at the diff was 163* after 5 hours of driving in the mountains. Granted, I wasn't towing anything. I've seen reports of temps over 220* in heavy towing. Not sure of the temp standard 80w-90 begins to break down.

 

the shop where I had my truetrac installed said regular gear oil not synthetic. They recommended changing it again after 1,000 miles as the parts wear in, still need to do that.

 

Thank you both! Just picked up 4 quarts of 80w90 for the install. You all have been a great help! :-)

James

 

Who are you having do your install? I ask because I'n in your neck of the woods.

I'm still fighting a vibration in my rig that surfaced right after the install. I don't believe it's anything to do with the TruTrac, but, I haven't located the actual source yet. I'll be back on the hunt this weekend.

 

Shouldn't you run 75w140 instead of 80W90? I know they make it in non synthetic, but really I can't see what synthetic would hurt to use anyways. Well after gear breakin anyways!

 

Eaton recommends non-synthetic gear oil. While they do not state 80w-90 is a specific requirement, the manual (I believe) states it is an acceptable oil for the unit. It also depends on where you live. With hotter climates, Eaton recommends 90w-140. Here's a clip from another forum where this was being discussed:

I'm not sure it gets hot enough in north Florida to warrant that weight, but, when I change my fluid shortly (have almost 3,000 miles on it) I'll use the 90w oil.

 

My install guy for ALL of my gear needs is a tech at Gainesville Ford dealership. His name is Dana and he is an "axle God".... if everything isn't perfect, he will tear it apart and do it again, but that rarely happens to him. The labor he charges me is not anymore than any of the local yahoos who think they know what they are doing around here.