Best rear end lube

What do you guys think the best rear end lube is out there thinking about going with 75/140 this time. thanks

 

I assume you are talking about your truck :-laf... I use Amsoil 75/90.

 

There was a pretty good thread about this subject & the popular opinion seemed to be that 75/90 fully synthetic was good unless you are towing heavy in the mountains or deserts. Then the 75/140 would be advised.



Joe F.

 

Yes I am I do a lot of pulling in the mountains of colo. about 90% of the time that is why I thought 75/140 may be better but some of the pulling is in the winter mouths.

 

To Buffalo, is the 75/140 a synthetic, and what brand do you recommend

 

I'm not sure about ALL 75/140's being fully synthetic. You may be able to get conventional fluids in that weight. 75/140 is like what 15w40 is to diesel engine oil. Most all oil manufacturers make their own version of that weight.



I can't recommend a particular gear oil in 75/140. My guess is that any MAJOR brand will be good. RedLine usually has very high quality products & I have run them in the differentials (75/90) with no problems. However, I have never had a differential problem that was lube related, or otherwise. Again, most major brands should work well.



I believe that a 'fully synthetic gear oil' is what is recommended for the differentials in these trucks. That's what I would use.



Joe F.

 

Last week, I went to my local Fleetpride and bought a 5 gallon pail of FULL synthetic 75/90w made by Smittys Refinery in the USA for $125, including tax. That's only $25. 00/gallon. I used 2 gallons more or less to change out both the front and rear diff on my 2005, which means I have enough for another change out in 15k miles, as well as some top-offs if my pinion seals continue to leak. Buying Valvoline or Mobil by the quart at Autozone or Kragens, it was at least $12/ quart--which is $50/gallon. The Stalube 1/2 gallon was $55. Fleetpride has always has the best prices on standard items (lube, oil, filters) for my Cummins, at least out here in CA. I am pretty sure that they had a 75/140 also made by Smitty Lube.
With the change out being called for every 15k miles, I am not sure it would be anyones cost benefit to run a more expensive synthetic oil.

 

Been running LE 607 ( now 1605 ) lube in my rigs. 214k on the '03 and no issues at all.

 

If you use a high quality 100 % Gear Lube, the 75W-90 is more than sufficient. Amsoil Inc. had some tests ran on several brands of Gear Lubes, and the 75W-90 100% synthetic was better overall. You can read the report here. The 75W-140 lubes are much more costly, and will actually run hotter in operation.

 

Does anyone recommend using Royal Purple 75W140 for the rear end?

 

I have been running Royal Purple for the last 35000 miles 85-140 with no problem.



Dave

 

Thanks Dave! I'll probably go with that.

 

MMEIER,



The LE-607 (Lubrication Engineer's) is supposed to be a very, high quality gear oil & it is not even a synthetic. Do you know much about the 1605? Haven't heard of that one. Is it their synthetic oil?



I know that Dr. Joe Donnelly has used the 607, in the past, & liked it. He's quite savvy on this stuff,also.



You have put your truck to the test by doing a lot of cross-country, commercial towing. If you're having good luck with the 607, that's a good testimony, in my opinion.



Joe F.

 

I've used the Amsoil gear lubes and I've found them to be really hard to beat. My towing is infrequent and I really don't have all that much HP. I run 75w90 or 80w90 depending on what brand I happen to be using.

 

I did mine in my driveway yesterday, and didn't miss any church. I bought a pail of Mobil Delvac Synthetic 75W90 from the local fuel distributor for $109. 14. I had to buy a pump to get it transfered from the pail to the pumpkins, and only spilled a little. It was a little overdue, 56,000, but the oil that came out was crystal clear, as was the transfer case. Just a little bit stuck to the magnets. One dealer here quoted $750 for everything, including the auto trans, which I had the dealer do previously. One day, I will tackle that too.

 

Joe, according to the people I chatted with at May Madness 2 weeks ago selling the stuff, the 1605 is the replacement for the 607. The 607 was like a straight 90 weight, the 1605 is 110 weight. They are interchangable also. You know pretty much what I have hauled in the truck besides commercial freight... ferrets, crazy blonds, and the like !!!:-laf

 

I have run 75-90 for some time (240k miles) running 10-12k trailer without a problem. To make mention, I work as a diesel/semi mechanic and the big boys run a 75-90 synthetic.

 

Amsoil

Ran Amsoil 75w140 since she was new. Pull 15k 5th wheel and have been very happpy with this in my rear end. . :-laf

 

I second that. I have a temp gauge for my diff and 75W-140 runs hotter then 75W-90. Redline 80W-140 runs hotter yet. I went back to 75W-90 because of this.

 

Amsoil

I use Amsoil severe Gear 75-140 my truck loves it! :--):--):--):--):--):--):--):--):--):--)