Synthetic Gear Lube

Run Run Away » running gear » Synthetic Gear Lube

Categories: running gear

Question:

Mobil 1 has worked well for me. I’ve now got 3500 miles on my 3 week old Silverado and will change front diff, transmission and transfer case to Mobil 1 with 5-10% moly additive.

Years ago I ran into problems in several manual transmissions that I attributed to Moly-slip. The syncro rings and cones were getting polished up and refused to work until re-knurled. Only replacing the gear oil with no Moly-slip solved the problem. I was tough on these syncro rings and I was using a full bottle (pint?) of Moly-Slip to the transmission. Molebnium di-sulfide worked fine everywhere else, no problems but no percieved gain either. We use it in industry in high pressure applications in gearboxes and as a grease. It is the main constituant in FWD CV joint grease I believe. I was studying up on mineral oil lubricants a while back noted the textbook advice on additives. The basic point was that unless one had the lab facilities to ascertain the necessity and compatability of certain additives, it is best to leave the tailoring of additives to the lubricant manufacturer. More is not always better. Steve Best, Nova Scotia, 4×4 van website: http://www.glinx.com/users/sbest

Response:

I use SEMI-synthetic in the diffs & tranny’s. Seems to work quite well even in the dead of winter. Sometimes adding some MOLY-SLIP to the tranny gives smoother shifting. In Canada we don’t surf, we Canoe! Cheers – Ross, Nepean, Ont, Cold Country Canada

Response:

I’d stick with an API certified lube, which Amsoil is not. Your information here is incorrect. AMSOIL XL-7500 is in fact API certified (see www.api.com for AMSOIL’s licensing). The 7500 stands for the recommended

That’s www.api.org. More specifically, http://www.api.org/programs_services/quality/enginoil.htm drain interval of 7,500 miles which AMSOIL does not hesitate to recommend.

However, the remainder (and more expensive) of Amsoil’s formulations remain *uncertified*. This makes them inappropriate for use in engines whose manufacturers require API certified oils. And the excuses for this lack of certification have been shown to be without substance, and in some cases outright lies. The major petroleum oil companies would love for you to continue to change every 3000 miles ($$) and some even attempt to make you feel guilty if you go past that.

I have to agree with this to a certain point. The Quaker State product that’s "formulated to last beyond 3000 miles" is just plain silly. However, nowhere do I see them recommending that you ignore your owner’s manual. They will not even recommend extended drain intervals when using their "synthetics", either because they cannot, or because they want your hard earned cash.

That’s because they’re *responsible* oil companies. They don’t want to encourage you to ignore your owner’s manual. Look in your car’s owner’s manual. More often than not, you’ll find ~7500 mile oil change intervals. Much (but not all) of the paranoia calling for shorter change intervals under ’severe’ conditions is just that: paranoia. Besides, under the right conditions you can push even the cheapest API certified motor oil a heck of a long way beyond 7500 miles. But if your owner’s manual says 3000 miles for ’severe’ service, it’s best to comply if you expect them to honor your warranty. The reason Amsoil pushes the extended drain intervals so heavily is that it is the only way they can justify the ridiculous price of their products. What kind of a company insists that you ignore your engine manufacturer’s recommendations? Certainly not a responsible company. What kind of a fool ignores their owner’s manual and dumps in *uncertified* oil and leaves it in way beyond the engine manufacturer’s recommendations? Probably the same kind of fool who thinks that joining an MLM and getting glossy propaganda brochures in the mail makes him an expert motor oils. <snip the typical True Believer testimony The unsubstantiated objections and negative comments you may read on USENET, made by people who know nothing about and have never used AMSOIL, will not change this fact.

Keep in mind that many of those objections and negative comments you may read on Usenet are made by people who know a heck of a lot more about motor oils than some get rich quick wannabee selling MLM motor oil out of his garage. Also, at least one of us naysayers used to make a pretty good living developing and testing motor oils for a large west coast oil company and can see right through the holes in the droids’ reasoning and the irrelevance and misleading character of the bulk of the ‘test results’ they post. Face it, Amsoil Inc.’s primary product is "home businesses". Their Amsoil motor oil, Altrum vitamins, Aggrand Fertilizer, and sundry other products exist merely to give their suck^H^H^H^Hdealers something to sell. $20 and a dealer number does not make one an expert on motor oils. — John Note: Email address munged in an attempt (probably futile) to foil spammers. There are no digits in the real address.

Response:

I am going to change the gear lube in my GMC K2500 – Eaton Locking rear end, transfer case and front differential. I was wondering if anyone out there has been using synthetic lube, and how they like it. Also, can I use a synthetic such as Mobil 1 or Amsoil in the locking rear end, or do I need an additive too?

Response:

I use it in my transfercase and axles. MUCH better on cold mornings. Steve Best, Nova Scotia, 4×4 van website: http://www.glinx.com/users/sbest

Response:

S. Best wrote…. I use it in my transfercase and axles. MUCH better on cold mornings I’m more concerned about the heat generated in the rear end when towing……the paint has already peeled off the cover. I’m not sure it is from heat, as I have close to 120,000 miles on the vehicle with no rear end problems.

Response:

I was just thinking….does the front differential and the transfer case churn the lube when not in 4×4? In other words, will synthetic lubricants in these areas offer less resistance in 2 wheel drive, hence improving mpg (possibly) at all times, or are synthetics used primarily for better protection?

Response:

My van is fulltime 4wd so it churns them all the time. As I mentioned, it made an enormous difference in cold weather starts where previously it felt like a park brake was stuck on. Even when fully warm there was a noticable difference in performance near top speed. This is an underpowered diesel so small differences are easy to notice. On my RWD car I noticed a top speed increase, slight but significant. I didn’t notice a difference in fuelmileage but I didn’t look for it either. I did notice all the running gear seems to run cooler to the touch with the synthetic, but this is a highly subjective way to measure! What I am using is Eaton Synthetic from a Freightliner dealership in the trucks and a Cdn Tire store brand synthetic (made by Exxon I believe) in the car. Both 75w85 or so, can’t remember right now. Most transfercases take ATF now-a-days, not gearlube any longer. Steve Best, Nova Scotia, 4×4 van website: http://www.glinx.com/users/sbest

Response:

I’d stick with an API certified lube, which Amsoil is not. Mobil 1 is a good synthetic lube, so is Redline. Redline has a differential lube that has the limited slip friction modifier already added to it. Jerry — Jerry Bransford PP-ASEL KC6TAY C.A.P. The Zen Hotdog… make me one with everything!

Response:

I’ve got a couple of hundred thousand miles with Mobil 1 in gearboxes and final drives. When one of the gearboxes failed, the mechanic told it looked great inside except for the failed bearing and that I must have changed oil regularly. I told I had over 100,000 miles on the trans, and he said they usually go out about 30,000 miles. He was impressed and told me to keep doing what I was doing. Mobil 1 has worked well for me. I’ve now got 3500 miles on my 3 week old Silverado and will change front diff, transmission and transfer case to Mobil 1 with 5-10% moly additive. — Mike

Response:

Only use straight gear oil in your Eaton locking rear axle. Adding an additive will break the case. I’ve seen it happen (mine) and it’s not a pretty sight. … – Hide quoted text — Show quoted text – I am going to change the gear lube in my GMC K2500 – Eaton Locking rear end, transfer case and front differential. I was wondering if anyone out there has been using synthetic lube, and how they like it. Also, can I use a synthetic such as Mobil 1 or Amsoil in the locking rear end, or do I need an additive too?

Response:

I’d stick with an API certified lube, which Amsoil is not.

Your information here is incorrect. AMSOIL XL-7500 is in fact API certified (see www.api.com for AMSOIL’s licensing). The 7500 stands for the recommended drain interval of 7,500 miles which AMSOIL does not hesitate to recommend. The major petroleum oil companies would love for you to continue to change every 3000 miles ($$) and some even attempt to make you feel guilty if you go past that. They will not even recommend extended drain intervals when using their "synthetics", either because they cannot, or because they want your hard earned cash. Why do you think a Mercedes Benz is factory-filled and sent to Europe with drain intervals set at 9,000 miles, while the same Mercedes is sent to the US with a recommended 3,000 mile drain interval? Believe me, it is not because the engines are any different. AMSOIL XL-7500 has been shown to be good for continued use far beyond 7,500 miles with proper filtration and periodic oil analysis. In addition, the rest of their products, although not currently certified, have been proven to meet and exceed certification requirements. I realize this is a sore subject for some people. There are those who might say "if it sounds to good to be true it usually is" (among other things). However this is not the case with AMSOIL! I’m sure many people will post back and say "just another sales droid". While I am a dealer, I would not have become one if my family and I had not used it for an extended period of time and tested the products ourselves. We have witnessed all of the benefits that are shared by us so-called "droids", as well as AMSOIL and all of their independent testing. Millions of satisfied customers have kept AMSOIL in business as the leader in synthetic lubrication since 1972. The unsubstantiated objections and negative comments you may read on USENET, made by people who know nothing about and have never used AMSOIL, will not change this fact.

Response:

I decided to go with the Mobil 1 in everything …. kind of a compromise. Mobil seems to be readily available (compared to Redline or Amsoil), and is about half the price of Redline. I can do both differentials, T-case, and tranny for about $75 (including filter). Since only about half of the old transmission fluid actually drains out of the transmission, I may drain it again in a few months to get a little better concentration of synthetic fluid.

Response:

There are a *few* Amsoil products that are API certified, I’m aware of that…. but I also know that most of Amsoil’s products are not API certified. I’d be willing to bet that if a total of Amsoil’s products were taken, there would be a very small minority that are API certified. A VERY small minority. And the fact remains that very few of us are fans of Amsoil… and those that ARE fans are generally always Amsoil dealers trying to make a little side money… and there’s nothing wrong with that. Jerry — Jerry Bransford PP-ASEL KC6TAY C.A.P. The Zen Hotdog… make me one with everything!

Run Run Away