What to look for when comparing synthetic gear oils?

[Darre Brune]

The rear end in my 1993 Mustang Coupe is getting a complete rebuild this week. I will be rebuilding the Trak-Lok and installing the extra clutch, new bearings (all of them), new 3.73's, solid pinion spacer, and all new seals. I was looking at several differnt brands of synthetic gear oils and was wondering what is/are the most important characteristic(s) that I need to be looking at and comparing? The car will see street duty and some track events. I have downloaded the data sheets for Royal Purple, Redline, Mobil 1, & Lucas Oil. I have also created a spreadsheet with the information from the data sheets so I can look at all of them on one page.

Examples would be Flash Point, viscosity, density, etc. Not too worried about the Pour Point as I live in SE Texas and winter here is jeans and a long sleeve shirt. Hurricane proof would be a plus.

Darren

 

[wantin150]

Have you looked at Amsoil, Speciality Formulations, and Motul? I don't know what your original specs were for the gear oil but the Amsoil Severe Gear 75W90 GL5 is supposed to be really good stuff. I have no tests to back this statement, just repeating from the Amsoil site.

 

[OiledMustangGT]

i would run some dino or cheap synthetic 75w-90 for 500 miles break in (there will be a good amount of break in metals), then switch to 75w-140 royal purple or redline syntetic.

i am running 75w-140 *might be 80w-140 or something, i forget exactly) redline in my 8.8 in south louisiana

 

[bruce381]

RL 75w/140 best out there and I make gear oils.
bruce

 

[Titan]

Make sure the bottle is from Specialty Formulations, and you can be sure it's a great product!

Where do I pick up my stipend check?

Seriously, any of those name-brand products should do fine. I just happen to use SF's products and like them.

 

[Pablo]

It's tough to shop gear oil by comparing specifications. People here seem to go by word of mouth, nothing scientific.

As stated most all the top names have more than enough EP protection (not available on data sheets), so I suggest you shop by high and low temperature actual viscosities. (not necessarily SAE grades) Do you want something as thick as possible? Maybe compare the viscosities of 75W-140's. Or compare the high temp. vis's of 75W-90's to each other.

 

[Steve S]

Bruce ,how would you rate Delo gear oil?

 

[1040 WreckerMan]

The Delo ESI gear lube is good stuff. It is the only non-synthetic oil to be Eaton LL approved for 750K mile drains (in HD on-road applications). I'm not sure what Eaton considers synthetic I must admit. We had good luck running the ESI in failure prone Meritor diffs, so the EP additives are certainly effective. Any of the oils mentioned so far in this thread will work well in your application, so it's a matter of preference and temperature/viscosity which oil you go with, IMHO anyway.

 

[bruce381]

quote:

---

Originally posted by Steve S:
Bruce ,how would you rate Delo gear oil?

---

The best NON syn and as good as about any syn gear oil out there. With the borate package it has a very long fluid life with low wear rates, good stuff high dollar for a GPII/GPI but good stuff.
bruce

 

[Steve S]

Thanks Bruce ,I like the Chevron Commercial products .

 

[LargeCarMan]

OiledMustangGT has the beginning answer....you need to change out fluid soon after the rebuild.

Wear metals will be high. If you spend big dollars on the rearend and want to protect it....buy a quality synthetic lube and change it out early "under 1000 miles" then refill again.

 

[OiledMustangGT]

couple pics from last yr's diff rebuild

changed the diff fluid on the new gearset after 700 miles ,for break in i was running 80w-90 RP



i think that baffle got slightly nicked when pinion bearings were pressed on, has not been a problem

 

[LargeCarMan]

Your point is well taken and as they say....?proof is in the pictures" That Redline was a blessing with your breakin and it still looks pretty nasty. Very good point.

 

[JohnBrowning]

I look at the Timken Load rateing and past experince. Redline has a proven track record and many more people use their gear lubes and transmission fluids then their engine oil!!! I recently tried Royal Purple based on it's spec.s and a lot of recent use by bracket racer and off roaders. It has a timken load rateing of over 140Lbs. wich is about 50lbs more then 80% of their competiton. I will say that the only thing I did not like about Royal Purple is that in my manual transmission it lost it's smooth shift feel after 10,000 miles of use. The first 10,000 it was drasticly smoother especialy in cold weather. It quickly lost that advantage over the OEM fluid theough especialy in cold weather.

Lucas really does not have enough track time in my book to be considered. I have not tried their gear lube yet but a site sponsor and long time member has a company that makes lubricants that are top notch! I would look at Specialty Formulations products. To date everyone that has used his products has had nothing but praise for them!

 

[Bror Jace]

Yep, with any of the really premium brands, I don't think you could go wrong. My preferences Begin with Specialty Formulations, go to Red Line and then maybe Amsoil.

Best advice is a short (1,000 miles or less) break in run with a cheaper product first. Get rid of all that free-floating metal bits!

Don't pay $12-15 locally for Mobil 1, Supertech or any other mass-market 'synthetic' gear oil. It's worth the effort to get the authentically premium stuff via net/mail order. You'll either break even or possibly even save some money getting the better product.

I've been desperately trying to find Chevron Delo products locally (other than their straight 30 and 15W-40 HDEOs) but simply can't. So, I ruled out using their premium mineral gear oils.

--- Bror Jace

 

[got_titan]

ive been using amsoil in my titan thats supercharged. just recently put in a truetrac and inspection of spider gears and ring gear looked perfect! amsoil severe gear 75-140 seemed to perform great!

 

[04SpecV]

Bror, Does advertising Specialty Formulations products every time you post on theVboard generate a lot profit for you?

 

[oli]

I changed the ford "lubed for life" 75W140 in a dana 60 L/S at 6 years and 55k. After it was in the pan and I saw, smelled, felt, and almost tasted the golden honey colored fluid, I was very tempted to put it back in. Also look at valvoline.

 

[Bror Jace]

"Bror, Does advertising Specialty Formulations products every time you post on theVboard generate a lot profit for you?"

Nope, not a bit. I paid retail for every drop I've ever gotten ... and have no other sort of deal with MolaKule.

I just really like the stuff. I must've, as it got me to stop using Red Line.

As I said in one recent thread over there, my job was to get at least one or two people there to try MTL-P and I just knew they'd take up the crusade. That happened several months ago.

I rarely post there anymore.

Actually, I've been surfing a lot less here too, lately.

--- Bror Jace

 

[Bror Jace]

Oh, and thanks, warstud. A new one opened up around here and I pass it everyday back and forth to work.

--- Bror Jace