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Technical => Drivetrain Tech => Topic started by: jgonza2 on January 06, 2008, 02:23:39 AM

Title: What gear oil to use in turbo coupe rear?
Post by: jgonza2 on January 06, 2008, 02:23:39 AM
I'm rebuilding a rear end out of a turbo coupe to swap for my one-legged 2.73.  I've been to Pep Boys and Autozone looking for the gear oil and I've gotten differing answers to which gear oil to use.  Anyone here know what it's supposed to be, and where to find it.

Thanks.

P.S.  How come my signature pic does not show up?
Title: What gear oil to use in turbo coupe rear?
Post by: Blown306Cougar on January 06, 2008, 02:43:58 AM
Quote from: jgonza2;196001
I'm rebuilding a rear end out of a turbo coupe to swap for my one-legged 2.73.  I've been to Pep Boys and Autozone looking for the gear oil and I've gotten differing answers to which gear oil to use.  Anyone here know what it's supposed to be, and where to find it.

Thanks.

80-90 or 85-140 pick one

Quote from: jgonza2;196001

P.S.  How come my signature pic does not show up?



i guess you did"nt do it right.. ;)
Title: What gear oil to use in turbo coupe rear?
Post by: stuntmannick on January 06, 2008, 07:56:13 AM
Don't forget to add friction modifier.
Title: What gear oil to use in turbo coupe rear?
Post by: ~AC on January 06, 2008, 08:20:43 AM
yeh the friction modifier is VERY important.  i had an old rear that i got rid of b/c i ran it without the modifier and the gears would whine like a skewed cat.  i didnt HAVE to get rid of it but i couldnt handle it anymore.  it'll burn the gears up without it to a certain degree.
Title: What gear oil to use in turbo coupe rear?
Post by: SLEEPER T-BIRD 87 on January 06, 2008, 08:39:47 AM
Quote from: ~AC;196016
yeh the friction modifier is VERY important.  i had an old rear that i got rid of b/c i ran it without the modifier and the gears would whine like a skewed cat.  i didnt HAVE to get rid of it but i couldnt handle it anymore.  it'll burn the gears up without it to a certain degree.


LoL

Without the additive the clutches in the limited slip unit tend to chatter (scrub one wheel) when turning instead of releasing smoothly.But some older well used units may pop and such but you wont get a whine like your describing wich sounds like the rear end you had either had the gear backlash setup wrong or it had a bad bearing.


Back to topic- i use synthetic 80/90 or 85/140 (severe use)
Title: What gear oil to use in turbo coupe rear?
Post by: ~AC on January 06, 2008, 08:53:02 AM
maybe the bearing started going bad after that gear-oil change? but it was a whine and a pop in my situation, open dif.
Title: What gear oil to use in turbo coupe rear?
Post by: SLEEPER T-BIRD 87 on January 06, 2008, 09:14:28 AM
Quote from: ~AC;196019
maybe the bearing started going bad after that gear-oil change? but it was a whine and a pop in my situation, open dif.



Possibly, Open diffs do not use friction modifier.
Title: What gear oil to use in turbo coupe rear?
Post by: ~AC on January 06, 2008, 09:23:58 AM
my owners manual back before i put it up too well said it needed it :x
Title: What gear oil to use in turbo coupe rear?
Post by: Tbird232ci on January 06, 2008, 10:40:34 AM
I used Royal Purple gear oil. It was a little expensive, but it made everything feel more smooth. I put it in my T5 and rear at the same time. Royal Purple also doesnt need friction modifier.
Title: What gear oil to use in turbo coupe rear?
Post by: jgonza2 on January 06, 2008, 04:15:47 PM
Quote from: Tbird232ci;196043
I used Royal Purple gear oil. It was a little expensive, but it made everything feel more smooth. I put it in my T5 and rear at the same time. Royal Purple also doesnt need friction modifier.


what weight on that royal purple?  I already purchased the bottle of friction modifier from Ford.  Would it hurt anything if I put it in with royal purple anyway. (The stuff stinks and I want to get rid of it.)
Title: What gear oil to use in turbo coupe rear?
Post by: bhazard on January 06, 2008, 04:45:31 PM
I used the mobil 1 at autozone, I think it was 75w90. Along with a tube of the friction modifier, TransX or whatever?
Title: What gear oil to use in turbo coupe rear?
Post by: ipsd on January 07, 2008, 09:50:44 AM
Quote from: jgonza2;196092
what weight on that royal purple?  I already purchased the bottle of friction modifier from Ford.  Would it hurt anything if I put it in with royal purple anyway. (The stuff stinks and I want to get rid of it.)

I have no clue about adding the modifier to the royal purple. But if you the think the modifier stinks when was the last time you opened a bottle of 80-90 or a rear diff? That be some stinky stuff right there.
Title: What gear oil to use in turbo coupe rear?
Post by: dominator on January 07, 2008, 06:09:56 PM
used mopar 75/140 synthetic
(since i work for dodge and it was free) in my tc rear and it works mint.
Title: What gear oil to use in turbo coupe rear?
Post by: jgonza2 on January 08, 2008, 01:23:49 PM
Quote from: ipsd;196245
I have no clue about adding the modifier to the royal purple. But if you the think the modifier stinks when was the last time you opened a bottle of 80-90 or a rear diff? That be some stinky stuff right there.


I haven't opened a bottle of 80-90 or the bottle of friction modifier I have...the stink comes through the sealed plastic bottle somehow.  The rearends I've opened have not smelled as bad as this friction modifier.

dominator said "used mopar 75/140 synthetic
(since i work for dodge and it was free) in my tc rear and it works mint."

How much to ship 3.5 pints of it to Calif? (lol)
Title: What gear oil to use in turbo coupe rear?
Post by: ~AC on January 08, 2008, 02:56:33 PM
heh this is kind of off topic, but we did maintenance on an 8.8 trac-lock and had used the friction modifier in it.  there was a guy that didnt last long there b/c he was a dick and a know it all that didnt know ANYTHING and he has the biggest toolbox in the world (i dont get that whole deal where guys have to have the biggest tool box in the shop) but his was so tall and he was a short guy, so we played a prank and took the tube of modifier on the top of his box where he couldnt reach... so after a week or so we couldnt handle the smell either so we clued him in and it wasnt a week later he quit.  good riddance!  the shop i worked at at the time had like 2 or 3 returns but when he was working there his cars kept coming back, i guess where he's from a return car is charged for the labor or something but we didnt do that at that shop, if it was a return for a problem we caused it was free.  i had to work on some stuff he did and messed up, i cant describe the stupidity!
Title: What gear oil to use in turbo coupe rear?
Post by: slowfoxbird on January 09, 2008, 09:11:14 AM
My personal favs are the Motorcraft XL-3 friction modifier, the blue colored skunk piss smelling stuff (I think its made by Dana), and the 75/140 full synthetic, probably the same as that Mopar stuff Dominator is talking about, just different labels.  I put that stuff in everything!
Title: What gear oil to use in turbo coupe rear?
Post by: santana on January 19, 2008, 08:09:57 PM
Royal Purple gear oil has some modifier in it. At least that was they said when I called asked about using their gear oil with the modifier. So I didn't add any modifier and my rear has been great. I used their auto trans oil in my T5 and no problems their either for the 5k miles since changing to their lubes.
Title: What gear oil to use in turbo coupe rear?
Post by: jcassity on January 20, 2008, 05:26:53 AM
Quote from: ~AC;196466
heh this is kind of off topic, but we did maintenance on an 8.8 trac-lock and had used the friction modifier in it.

please explain to us technically "why" since you insisted on it.


Quote from: ~AC;196466

 there was a guy that didnt last long there b/c he was a dick and a know it all that didnt know ANYTHING and he has the biggest toolbox in the world (i dont get that whole deal where guys have to have the biggest tool box in the shop) but his was so tall and he was a short guy, so we played a prank and took the tube of modifier on the top of his box where he couldnt reach... so after a week or so we couldnt handle the smell either so we clued him in and it wasnt a week later he quit.

is this a sentence?


Quote from: ~AC;196466

good riddance!  the shop i worked at at the time had like 2 or 3 returns but when he was working there his cars kept coming back, i guess where he's from a return car is charged for the labor or something but we didnt do that at that shop, if it was a return for a problem we caused it was free.  i had to work on some stuff he did and messed up, i cant describe the stupidity!

You should start showing off your highly experienced talent since your a mechanic.
Title: What gear oil to use in turbo coupe rear?
Post by: jcassity on January 20, 2008, 05:33:55 AM
Like mentioned,, gear box oil.

Now, if your looking for the good stuff thats not all full of gimics, get 85w140.  Thats some real sticky stuff to and its really hard to wipe off.  Its the color of regular motor oil to but sticks to everything.

Its easy to find but common at tractor supply places since its used in the south as PTO or Hydraulic fliud.
Title: What gear oil to use in turbo coupe rear?
Post by: vinnietbird on January 26, 2008, 08:26:23 AM
Mobil 1 in my car.
Title: What gear oil to use in turbo coupe rear?
Post by: dominator on January 26, 2008, 11:51:53 AM
Yea lets put tractor oil in our diffs,OOOOOOOOOOOOOOOOOOOOOK.
SYNTHETIC OIL IS NOT "All full of Gimicks"it's the best oil there is hands down,more purified than any regular petro based oil.
Dude stop being hard on the guy,he's saying that the guy had too many comebacks and he was a dick,i get that completly working in a shop.
One bell end ruins the whole thing.
Title: What gear oil to use in turbo coupe rear?
Post by: Thunder Chicken on January 26, 2008, 05:05:07 PM
I put Castrol 85W90 synthetic with the Ford blue skunk piss smelling stuff in mine (it came with the rebuild kit). And it is one of the smelliest, most difficult to remove smells there is.

Years ago when I had my '87 Sport I had to do the wheel bearings, so I got permission from the service manager at the Pontiac dealership I was a service advisor at, brought it in the shop on a Saturday, and replaced the bearings and axles. While doing so I managed to spill some of the used rear end oil on the shop floor. I wiped it up with a rag and forgot about it...

...until Monday, when I walked into the dealership and the entire building, from the showroom to the lunch room to the offices to the shop, stunk like Ford friction modifier. Naturally, I was not very popular there for a few days...


Another fluid that stinks really bad and is really hard to get rid of is carburetor cleaner. I soaked some carburetors from an old outboard motor in some late last summer and I swear I can STILL smell that shiznit in the garage.
Title: What gear oil to use in turbo coupe rear?
Post by: JrP on January 26, 2008, 07:09:47 PM
Make sure the oil you pick is at least gl-5 rated or even better gl-6.(gl-6 rating,this is better suited for harsh environments and gear ratios 373:1 and above.)
Title: What gear oil to use in turbo coupe rear?
Post by: jgonza2 on February 01, 2008, 02:54:33 AM
Thanks guys!  I appreciate everyone's input.  I'm leaning toward the Lucas 85w140 (JCassity hasn't let me down yet) although I wish I could use synthetic to give it a bit of an edge.  But I got this 7.5 rearend at the salvage yard and my plan was to rebuild the traction lok by replacing the clutches, but I was unable to find the clutch pak anywhere.

So, I'm just going to install it the way it is, with fresh gear oil, and see what happens.  There's a shop not too far from me that told me that they will charge me $600 to replace the traction lok with a new/rebuilt one if it doesn't work for me.  I'm hesitant to spend the extra money on synthetic gear oil if it's going to be dumped out within a few miles.