Larry whats your opinion on running syth. gear lube?

[Lloyd Smale]

Going to change out the tranny (90w) and the transfer case (automatic trans fluid) in my wrangler. Do you feel theres any wear benifits to this. Im sure theres a bit of gas milage savings to be had but thats not my major consern. Im more intersted in longevity.

[SHOOTALL]

We use in in our trucks ( pick ups , vans and stake body trucks) . We went thru. about 6 rear ends mostly GM then switched to syn. grease and have had no more failures. The first failures were with in 150000 miles we now have some that went over 300000 miles. The one Ford rear ( really 2 ) was dealer fault. No grease in rear at delivery and replacement installed with out grease , third rear was the charm. The other 5 were GM corporate rears. We started with Amsoil but now use NAPA , Valvoline or Pennzoil. And yes fuel millage will be a bit better.
 One caution if the rear is old it might leak with syn.

[Larry L]

Lloyd, when it comes to ATFs, there are no non-synthetics on the market anymore....assuming yer talking a name brand. There may be some off brand that I'm not aware of that might not be a synthetic. You didn't state the year model of the Jeep but if it's a Chrysler made Jeep, use ONLY ATF+4 Mopar fluid. This is a highly specific fluid and any after market fluids will not be as good regardless of price.


In regards to the manual transmission fluid, you didn't say which manual transmission you have and they all don't use the same fluid. You're going to see various viscosities recommended for them from 10w-30 motor oil to 75-140 grease. Your saying 90 but that's only part of the spec. GF-4 or GF-5? Actual viscosity range would be helpful. If it has the NV3550, I'd suggest Royal Purple Synchromax. It's GF-4 and 5 compliant so there's little issue with corrosion as there could be with a GF-5 fluid in a yellow metal transmission rated for GF-4. Ya just can't stick most anything in them anymore and get maximum life out of them. Everything is highly speced on these units today.


Shootall, welcome to the world of GM. Their grease specs suck as you've found out. But they say it's great as long as you're changing per maker recommendation at every 30,000 miles.....like as if anybody does. The synthetic base isn't the cause of any leaks. If you have seals going bad, it's usually because of bearing wear which is allowing the axle to beat the seal out. Otherwise, there's not a lot of pressure on the seals like in a pressurized lube system. Or to better say it, if the seals start to leak, change the bearings and seals together or expect the same leaks. Any fuel mileage gains are more attributed to formulation rather than the synthetic base. No synthetic base brings more lubricity to the job over a conventional base.

[JonnyReb]

  Really glad this topic came up as i know ..someone has the answer.

  The only manual transmission i have is in my little fishin truck, a 97' tacoma with the 2.4 and a 5spd. Its a great little truck and i love it, after 240,000 miles it has never let me down and is original for the most part, i think i put a starter on at about 180,000 and did change the ball joints. A more reliable vehicle i haven't come across. Anyways..at about 150,000 i decided to change the gear lube in the tranny. It was getting a little sticky when i shifted and i knew it shoulda been done years before. I bought Royal Purple 75\90 and replaced the fluid. When i ran through the gears it was like steel on ice, smoother than i'd hoped. Drove about 5 miles and it would barely shift Sticky in every gear. I went back to the auto parts store and bought the cheapest stuff they had in a 75/90, made by coastal. I drained the royal purple and put the coastal in, within a few miles it was working pretty good, and i just left it alone. At 235,000 miles it was also shifting rough and i changed it, using valvoline this time, 75\90, and its better than the coastal was, even when new i think but not like i remember the factory stuff to be. The factory stuff seemed best.

 My question is, why did the high end Royal Purple make my box so notchy? Was an expensive mistake though and even though i'd prefer to use a "best" product, am i best to just stick with "plain" lubes, as some of the toyota forums seem to recommend? Thanks!   Jeff

[SHOOTALL]

We do follow the spec now .

[Larry L]

JonnyReb, hard to say exactly. Toyota manual transmissions can take a variety of lubes including a hypoid oil, ATF, and even motor oil. My bros 97 Taco 4x4 takes ATF in his 5 speed. The RP covers the GF-4 and GF-5 specs because it's buffered to prevent corrosion. That keeps the yellow metals like bronze from corroding. The RP could have loosened up varnish and that was the reason for the notchy- it could be a list of things. Yours however, is GF-4 rated if it uses a hypoid oil. With any of the car makers, you can't always go by the owners manuals. You need to know exactly which transmission you have and use the makers recommendations. Few of the auto makers actually make their own manual trannys.


The better hypoid oils will smell bad, if it don't, you don't want it. The smell is the sulfur content that is usually accompanied by phosphorus. A good oil will also be black due to the Moly Disulfide content. All of these are extreme pressure agents that an axle or a manual transmission that requires a hypoid oil needs to prevent scuffing and wear. That applies to an open axle only. Some of the locking type differentials require an alcohol modified lube to keep the clutches from tearing themselves apart. If you have a locking differential, you'd better be changing axle lube every 30,000 miles or expect failure. These types of differentials are not forgiving.

[JonnyReb]

 Thank you very much Larry, sounds like the toyotas gearboxes may be quite forgiving and i'm pleased to hear that the RP itself probably wasn't the issue. You've give me a lot to ponder, any benefit or reason to run ATF or motor oil in the gearbox? Also it makes perfect sense that lubes with lots of sulpher, phosphorus and moly would be a good thing..any in particular you know to be excellent products that you would recommend? Thanks again for taking the time to share your knowledge.  J

[Larry L]

If it were my unit and it used a hypoid oil, it would get Chevrons Delo Gear Oil ESI. If the unit were to be carrying a heavy load or had a trailer that lived on the hitch, I'd also include a bottle of LubeGards Fluid Supplement. It's an ester enriched product in a blend of base oils. If the shifting has been an issue, LubeGard  should take care of it and keep it nice and clean inside too. The ester has incredible film strength that adds to the basic gear oil formulation providing a tough film between parts.
http://www.lubegard.com/~/C-197/LUBEGARD+Gear+Fluid+Supplement


Finding these products in your area may be an issue. Chevron chases a lot of the commercial market but they have no apparent interest in the retail market. Product availability has always been an issue with Chevron. They are probably the best manufacturer of lube products in the world.

[Lloyd Smale]

larry the tranny takes 75-90 g4. I ordered redline synthetic. Did i make a mistake. I know some on the jeep forum claim its interchangeable with 10w30 motor oil and some prefer it.

[Lloyd Smale]

Larry i ordered a bottle of lubegard from napa. Just checking with you though to make sure its not going to react with the metal in my tranny.

[Larry L]

Assuming yer not going on a trip across the arctic, the Redline should be alright. It's more like a 10w-40 than a 10w-30 oil. You MIGHT have a feeling of a heavy or slow shifting unit. The only way to know for sure is to try it. The LubeGard will add significantly to the extreme pressure agents that any manual transmission desperately needs. Shearing in these units is incredible. The added esters will pay for themselves over the long haul. The LubeGard works in any and all manual transmissions.
Gotta love those NAPA guys.

[FPH]

I have a friend who has been a tranny rebuilder for 30 + years.  Lubegard is the only additive he recommends.

[Lloyd Smale]

larry, ive been told that the 90 wt lube can be substituded with 10w30. Would i be smart if you think this is a bit thick to put a quart of 5w30 synthentic in lew of one of the quarts of 90wt? Would that thin it down some?

[Larry L]

No, do not mix anything with it except maybe the LubeGard. Redine runs a lot of additives in all of their formulations and adding something different can throw it out of balance quick. It can go from a top shelf product to crap with less than a qt of something else. Assuming that this is the product you ordered:
http://www.redlineoil.com/product.aspx?pid=46&pcid=7
I see no approvals or meeting any factory or SAE specs. Redline makes good products but if you are having doubts about using it- maybe you shouldn't. Doesn't sound like you have 100% faith in it. Take the time to read about test procedures concerning gear oils. This one is mostly about the SAE J2360. If it meets the specifications you desire, look for a gear oil meeting this spec. Knowing that Chevrons ESI meets specs for Eaton and Rockwell and the fluid is good in those units up to 750,000 miles, I'd still recommend it.
http://www.swri.org/4org/d08/Abstracts/GearOil.pdf
http://www.colemanoil.com/DrawProducts.aspx?Action=GetDetails&ProductID=7

[Lloyd Smale]

thanks again larry. Are these the specs your refering to? http://www.redlineoil.com/content/files/tech/Man%20Trans%20Lubes%20PDS%208-10.pdf

[Larry L]

The properties sheet you posted has nothing to do with certifications. Redline like some of the other boutique oil blenders do not spend the money to get their products certified. Doesn't mean they are bad or trying to be deceptive, just won't spend the money for the tests which CAN run into the million dollar mark. I remembered reading a study about gear oils that also included Redline and it's for the one you have coming. To cut to the meat of the study, the Redline failed at oxidation and it exceeded API standards in cold performance.....that means it failed there too. But the cold test is run at -40C. Unless you have those kind of temps, the data is irrelevant. But at extreme cold it will have the thickness of chocolate syrup, just so you know. Down here in Texas we hardly ever see anything at a minus temp and some years it never hits freezing. May be different at yer house. Anyway, here's the study. The best sentence in the study is that any lube is only as good as the weakest link.
http://www.goodsenseoil.com/G2457-GearOilWhitePaper.pdf