Should i add lucas to my differential ?

[kcfirstbuild]

Should is use Lucas oil stabilizer in my differential with a quart of 80-90 or should i use two quarts of " lucas 80-90 gear oil" or just use two quarts of 80-90 and be done with it. I have 12 bolt on my 1968 c-10. I have been using lucas of a long time and just thought since i was changing the fluid out i might use some in the rear . but wanted to hear what everyone thought.

I'm going to stay away from synthetics, im not building a speed demon.

[Shyguy]

I have never used any Lucas in a differential, but would be interested in what others have to say.

[cdowns]

best bang for the buck is synthetic// i use only mobil one or roryal purple in everything i own

[oldblue1968chevy]

Why not run synthetic, ive heard its the way to go on rearends..

[msgross]

I used lucas synthetic in the rear diff of my daily driver, stopped the posi-chatter (added additive as well) and shouldn't have an issue ever... it's a little cheaper than royal purple

[kcfirstbuild]

To many stories of syn leaking in older vehicles. maybe they had other problems too

Would like to find some one that put lucas in before i become the Guinea pig.

It says right on the bottle for diff's though

[kcfirstbuild]

what about just the oil stab from lucas and a quart of 80-90 ?

[Rob H.]

I haven't tried it in a rear end but works great in an auto tranny! I'm sold on their products.

[Longhorn Man]

new oils don't need additives. Most synthetics don't even need posi lube added.
There is no real reason NOT to use a quality synthetic lube with the exception of cost. And if it leaks after filling with synthetic, you already had a problem.
While some of the lucas additives are worth something, some of them are snake oil. I highly doubt there is anything in there gear lube that a quality synthetic lube doesn't already have.

[1969stepside]

80-90 conventional valvoline is all i use

[yote1234]

lucas. shure..i did.

[LONGHAIR]

Originally Posted by Longhorn Man

new oils don't need additives. Most synthetics don't even need posi lube added.
There is no real reason NOT to use a quality synthetic lube with the exception of cost. And if it leaks after filling with synthetic, you already had a problem.
While some of the lucas additives are worth something, some of them are snake oil. I highly doubt there is anything in there gear lube that a quality synthetic lube doesn't already have.

ZZZactly^^^

The only thing that I would add is that I would definately run a synthetic with new gears, from day one. The heat generated by the rear gears is significant and synthetics deal with it much better.

[kcfirstbuild]

They are 42 year old gears. I did put new seal, bearings and cover gasket so nothing should leak.

Ill just put some fresh 80/90 in.

[mdwilf]

I know this might sound like a "fishing story", but it's true.

Anyway... I had a 72 1/2 ton 2wd that had been run really, really low on rear diff oil - sounded like a jet at full throttle going down the road. I drained it & filled it will Lucas Oil Stabilizer & within a few miles it was almost totally silent. I ran it several years that way (prob 6 or 8k miles) - towing, scrapping, yanking, etc. It finally died when I got stuck during an ice storm & decided I'd get it out or break something. Ended up being the latter - came apart so hard that gear pieces dimpled the housing & it wouldn't hold fluid anymore.

I'm not 100% convinced that Lucas will do much more for your motor than slow oil consumption, but it was amazing what it did in that rear end.

[Davetopay]

In my Mustang I used the Lucas Diff lube in the rear end and the Trak-Lock never once chattered, and it grabbed like a mofo. No wear issues either. I would drain it once a year for inspection and a general checkup as it was routinely launched a 5000+rpm with a side step of the clutch.