grumppyoldman
Well-known member
What gear oil should be used in the rear end 0f a 55 Fairlane with an 8" 3;30 to 1/ ratio? Al
Rear eend gear oil
- Thread starter grumppyoldman
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Daves55Sedan
Well-known member
90 wt gear oil is recommended for a stock rear end. If it has been converted to posi-track, you will need to add a tube of posi-lube. Does not matter what the gear ratio is.
grumppyoldman
Well-known member
the climate down here is hotter than where you guys live, so I think I should use the 140 wt. thanks for the info. Al
rotorwrench
Well-known member
I use SAE 85W/140 for south Texas climate. Northerners can us the SAE 80W/90. It's getting harder to find the straight grades. I have to buy SWEPCO 201 SAE-90 for the Robinson helicopters due to there specification for straight grade only with a blue color so you can tell it's in there. That stuff is more expensive than the SAE 85W/140 at the local lubricant supply distributor we use.
slumlord44
Senior Member
If my memory serves me right it must be HP rated.
rotorwrench
Well-known member
I can't remember how good my memory is. Gear lubricants are EP rated for the content of extra pressure additives. Rear axles generally have no phosphor bronze bushings unless they are very old worm drive types so it really doesn't matter what EP rating is used. Hypoid type axles really should have EP5 if they are used a lot for hauling heavy loads such as in a large car, pickup, or a large truck otherwise an EP4 would work.
Transmissions from the early ford years have the soft yellow metals so they should use EP4 or less to prevent acidic deterioration of the soft metals.
Transmissions from the early ford years have the soft yellow metals so they should use EP4 or less to prevent acidic deterioration of the soft metals.
