Lucas Oil - Heavy Duty

[treegump]

Just went pass 200k on the odometer, and was wondering if it wouldn't be a bad idea to add a quart of Heavy Duty Oil (from Lucas Oil) with my next oil change, and also put a quart of Heavy Duty Oil 80W-90 in my diffs & NV4500. My NV4500 has been leaking, and been getting worse since November, but I'm pretty sure its a gasket.

None-the-less, its pretty thick stuff - consistency of Molasses on a cold day, so curious if there'd be any concern about it hurting it. If it doesn't help, then it doesn't help...just don't want to make anything worse, you know?

 

[6.2 turbo]

If you put it in the tranny it will shift hard when cold. Some people say Lucas is no good. A few years ago I built a sbc 400 with a flat tappet Comp cam. I always ran 15w40 Castrol and a 1/2 bottle of Lucas. After 40,000 miles the lifters look like brand new,which is rare for a flat tappet,at least for me anyhow.