Engine/Transmission (1998.5 - 2002) Rear differential fluid

[Paulsdodge]

Ok guys I need your help again,



I have a 2001 HO with the six speed and a Dana 80 limited slip differential. Soon it will be time to change the differential fluid and the friction modifier. The 2001 DC service manual calls for 75w-140 synthetic gear dope. I have looked everywhere local, and I have even looked at Amsoil's page. I cannot find any fluid that meets DC spec. Worse yet, I am willing to try a different fluid, but if I have any problems, I know that is the first thing the dealer will scream, incorrect oil--- no warranty. :--) What would y'all suggest as a replacement fliud? The dealer wants 19. 00 a quart and I need almost a gallon to change the fluid. :--)

 

[dresslered]

Roy at Mag-Hytec highly recommended the LE-607 along with the cover. This brings the capacity up to 8 quarts. He said that unless you are really towing heavy, he would recommend the above over the 75w-140 (even though he carries both). I have been very happy with the choice.

 

[Gary - K7GLD]

Some members have mentioned that Pennzoil is now marketing a differential lube for our trucks that meets the DC spec - check your local Walmart, Kragen or Grand Auto... The yellow quart bottles over in the gear grease section should really stand out, and check the fine print carefully to make sure it's the right stuff...



But *I* haven't seen any yet locally...

 

[dan_gilson]

Roy is 1st class. I got his cover and oil. Machining on the cover looked really good. The cover changes the capacity to 8qts. 1 call did it all and it arrived shortly there after.

 

[Paulsdodge]

What is the internet address for Roy???

 

[dresslered]

http://www.mag-hytec.com



P. S. With the LE-607, I ended up only useing one bottle of friction modifier. Add a little at a time, go do some figure-eights in the parking lot, and then add a little more as needed. Adding too much will defeat your LSD.

 

[Diesel Gunner]

Used Friction Modifier as Recommended

I installed the rear cover with the Le-607 and added the recommended amount of friction modifier with no problems.



My trailer grosses at 10,800 and I usually go out heavy. I have not noticed any problems so far. Axle usually runs at or about 175-210 while pulling trailer depending on speed and terrain.

 

[John Berger]

Roy is a first class guy and treated me well. I love the Mag-Hytec. I have one on my differential and my neighbor has one on his auto transmission. The Amsoil Series 2000 75W-140 has been very good in my differential.

 

[HBarlow]

Differential Lube

The 2001 owner's manual suggests using synthetic differential lube when doing a lot of towing, which most of us do. I use Pennzoil Synthetic lube purchased from Wal-Mart in the yellow quart bottles for about $6/quart. I think it is 75w/90 weight and is GL5, the required specification. Oddly, the quart bottles are marketed as Marine Lower Unit lube. NAPA offers the same 75w/90 GL5 synthetic, not packaged as marine lube, but is $8 or $9/qt.

 

[amsoilman]

Amsoil Inc. does make a 75W-140 "Full Synthetic" gear lube but the 75W-90 is what most people use. Personaly, I think the 75W-140 is "overkill". I had mine tested with 60,000 miles on it, and the viscosity tested the same as the new stuff at 15. 1 cSt@100C.

This tells me it is not breaking down at all. I also have the Mag-Hytec cover as well as the deep dish oil pan for the trans. Roy from Mag-Hytec is first class!





Wayne

amsoilman

 

[Pit Bull]

Make sure whatever brand you choose is MT-1 rated so you don't have any seal problems. It's funny how many are not MT-1 rated.

 

[alaterreur]

Maghytec cover oil amont

I have a Magtec cover that was just put it. I know the paper says to put 8 quarts in the rear end, is this too much? That would put the level alot higher than normal. I do not was to blow seals.

 

[Texas Diesel]

Most autoparts stores sell Mobil 1 90W gear oil for about $5 a quart. It is fantastic stuff and readily available. There was a post here not too long ago about how Eaton would extend the warranty for over-the-road trucks from 100k to 700k miles (differential) if the operator would switch to Mobile 1 . No other oil can claim that, good enough for me. I noticed a 20* or so drop (towing) when I put Mobil 1 in amd I needed less friction modifier. Mobil 1 meets DC's specs and was recommended by the dealership.



Seems to me that I put in about 7. 5 quarts, just to the upper line on the MagHytec dipstick.

 

[Texas Diesel]

Here is a good thread and the Eaton warranty thing towards the bottom.



https://www.turbodieselregister.com...threadid=38708&highlight=eaton+warranty+mobil



Read the post by gmorrison



I just checked with Carquest and they said it was now $13 a quart

 

[dresslered]

alaterreur-

It really depends on whether you get all the old oil out or not. I actually raised the truck on both sides to let the old oil run out of the axle tubes. Eight quarts brought me right to the proper level.



Also, if your truck has been lifted or modified in a way that the axle has been rotated, you will have to re-establish the level marks.

 

[John Berger]

75W-140 is overkill?

Wayne, I've heard that from you and others before. I've run the 2K 90 weight lube with good results. I went with the 75W-140 due to the heat and humidity where I live. I'm not questioning the overkill statement, but let's assume that it is overkill. What would be the circumstances that it would not be overkill? TIA.



John

 

[Oil Man]

phumerick,

You asked for the web site for Mag-hytec. It is Mag-Hytec.com

They recommend the LE 607 and the LE 9920 gear oils. Their number is 818-786-8325. The guy to talk to is Jerry.



Sincerely,

Kevin Dinwiddie

 

[Pit Bull]

Originally posted by Texas Diesel

Most autoparts stores sell Mobil 1 90W gear oil for about $5 a quart. It is fantastic stuff and readily available.

Texas Diesel, I would love to use Mobil 1 gear lube (very easy to find) but I noticed it was not MT-1 rated. I was lead to believe that the MT-1 rating was very important. What are your thoughts on that? How long have you run the Mobil 1 lube and have you had any seal failures?

 

[amsoilman]

MT-1 refers to the ability of a lubricant containing (EP) Extreme Pressure additives to function in elevated temperature applications without corrosive by-products. It is an API rating.



EP additives are used in severe service applications where high loads, sliding pressures and shock exists. The amsoil gear lubes use sulfur/phosphorous compounds as the EP additive.





Wayne

amsoilman

 

[amsoilman]

John,

IF I were hauling 40,000 lbs on a consistant basis, I would use the 75W-140 gear lube. Since I rarely haul over 16,000 lbs. a dozen times a year, I use the 75W-90.







Wayne

amsoilman