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Discussion Starter #1
Recently replaced factory limited slip with spool, just out of curiosity, what gear oil is everyone running? Not needing to run a additive now, is everyone sticking to a synthetic 75-140, 75-90?
 

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I run 75-140 Royal Purple gear oil in my spooled 8.8. Currently with a 4.10:1 gear. No problems after 3 seasons.
 

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No need to keep clutch packs coated so you will only need 1.5 qts.

With a stock cover or extra capacity diff cover?? Why run shy? What about the ring a pinion?
 

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Also I’d run whatever diff fluid is recommended by the gear company. Since there’s no locker, then it’s easy just to go by whatever the ring and pinion call for.
 
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With a stock cover or extra capacity diff cover?? Why run shy? What about the ring a pinion?
If for drag racing only, no need for a full diff. A full diff of oil causes windage and drag. I only run 1 qrt in the diff. It dose not operate long enough to build any heat.
 
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With a stock cover or extra capacity diff cover?? Why run shy? What about the ring a pinion?
If for drag racing only, no need for a full diff. A full diff of oil causes windage and drag. I only run 1 qrt in the diff. It dose not operate long enough to build any heat.
Ok, I can see this. Drag race only I would say I agree. I run my car on the street w/ spool. I just filled it until it came out of the fill hole. Didn’t really put much thought into it one way or the other. Good info
 

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Try running without oil.

You'll be surprised how much heat there is.

the cheapest 80w90 has always proven to be more consistent than 75w140 or any synthetic, at least in my case (built 9"). 14 years so far on the same gears, case, axles, everything. Knock on wood. Has not been apart or even drained, but it does build some heat after a pass even with 2 1/2 qts of lube in it.
 

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if you drive it smartly, it’s really not bad. I Just have to remember it’s there and drive the car like it has a spool in it. It’s nice knowing the lockup is always there
 

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LOL, actually yes, depending on your tires, that’s a good point. I run my tire pressure higher when I’m planning on street cruising. But again, I plan where I drive to avoid tight turns. Other than tight turns I barely know it’s there. With that said, I highly recommend sticking with a locker if any car is strictly a street car. At the power level I’m at I felt more comfortable with 35 spline axles and a spool for track use, so I have to take the good with the bad.
I think a huge factor in a cars “streetability” that is overlooked is where you live and what the road conditions are like. What works for me might not work for someone in another part of the country. My car wouldn’t last a week in a city for example.
 

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I also drive with my ARB hooked up, manual brakes and manual steering. So take my advice for what it is LOL
 

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Discussion Starter #18
Thanks! No real street use here, I’ll wait until I can afford a locker to do that, but I was wondering about tight maneuvering between the shop and the trailer on pavement. On my trucks front axle with manual lockouts, I’m using a spool. In the grass it’s fine, but as soon as you get that traction, she starts bucking real bad! However, that is the steering axle of my toy hauler, and the spool is on the drive axles of the car, so I basically have 0 experience with one.
 

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I ran a spool on the street for a while, and all I remember is that in a turn at speed the car went from mild push to snap over-steer in a hurry. Lol.
 

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I would never run my rear end low on lube. The rear gear only turns so slow and accelerates so slow and torque is so high you would never measure the change in power, but I'd bet money it would cause a change in bearing or gear life.

I would never waste a penny on a special lube. I get about 1 to 1-1/2 years out of a gear set now that Ford gets them from Motive gear or whoever. I'm at a 60 foot time where 35 spline axles gradually twist. The issue 100% of the time is the gear teeth are too brittle and eventually start to chunk off.

I went past my normal inspection time. When I pulled the cover I could push chips out of the ring gear and pinion gear with a screwdriver. The failure issue is always a tooth fracturing or breaking off, it is never an issue from lube quality. When the gear is ready to break it will start showing different depth surface lines in the pattern either on the pinion or the ring or both. I went way past the safe point on this round.
 

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