I know specs call for 75-140 but all they had in the Lucas was 85-140, will this be ok or should I go with another brand in 75-140?

 

The only Lucas 85-140W gear lube they make is dino (non synthetic). Lucas does make a 75-140W is their red label Synthetic line, but it isn't as easy to find. I dunno if the 04's require synthetic like my 07, but if they do I would swap it out for the red label if you can find it, or a different brand in synthetic.

nateroach

 

you will have no issues with the 75w-140 synthetic; napa stores has that brand and I believe with the lsd additive already in the bottle. Also it is recommended btw

 

ok thats why I posted, just did not seem right. will swap it out for mobil 1 they had that.
I just like Lucas from motocross days.
Thanks

 

been there done that mobile 1 is a quality oil. no doubt. I use it in my h-d. but for the rears and the front diff's I use valvoline full syn it has the additives and it's less on the wallet. but too each his own, enjoy. glad I could help

 

sold, LOL yea I use to use cases of valvoline motor oil in the good ol days in my 225 slant 6 1970 duster with headers 4 brl holly and edelbroc intake. sounded like a heard bumble bees comin down the road. LOL
thanks again

 

I use the 85w-140 conventional Lucas in my rear diff and its fine. I can't use synthetic oil as with a Auburn LSD it's taboo.

I just make sure I change it every 15k like clockwork. I run a full synthetic in the front and change it every second time I do the rear...

 

85-140 means a little thicker when cold but the same thickness when up to temp