Gear oil

Is it O.K. to use GL 5 in the rear end of a Shoebox Ford?

 

I'd stick with 80w90

 

Should be okay if it's the right "weight" (viscosity). The problem with GL5 is the additives attack the brass syncro rings in transmissions........it does no harm to steel and iron parts. To my knowledge, there is no brass in most rear ends and shoebox axle in particular.

Ray

 

Hummm....

The car has gone at least 60 years without it, why use it now?!?!

I say stick to what good 'ol Henry put in it in the first place.

 

If you can get , agreed. The problem is the supercession of older formula oils with the newer blends has led to availability problems in some cases. GL3 went to GL4, GL4 is superceded by GL5 etc. etc.

I found this out when trying to buy GL4 in the past year....checked all the local auto parts supply houses, farm stores, etc...no luck....ended up ordering online from Red Line Racing oil.


Ray

 

I hear ya... I stopped by an "Auto-Zone" while on the road this weekend and found out that they only stock multi weight motor oils... No straight 30 or 40!

 

These guys have GL-1.

http://www.fifthaveinternetgarage.com/parts/parts_counter_3.html

Perhaps a search would reveal some other choices as well.

 

except possibly in the bearings(spacers)

 

I talked with a representative from Lucas Co. today. I was using a Lucas gear oil product but he said not to use the one I was using because of the GL5 soft metal issue. He recommended using a 50/50 mix of Lucas H D SAE 80-90 gear oil with the Lucas Synthetic Oil Stabilizer. The stabilizer will bring the viscosity up and protect all metals. The part #,s are 10043 for the oil and 10130 for the stabilizer. Note dealing with Lucas was just like the old days. I called the number on the bottle and the guy that answered the phone had all the information I needed. I did get an education.

 

^^^^ this is good info.I use lucas products in all my stuff.

 

I was looking at the Lucas Stabilizer, too, and saw it can be used up to 100% according to the wording on the bottle.

Gary

 

I've purchased GL-4 at NAPA.
STA-LUBE GL-4 85/90
Part# SL24239

 

Again I was told by Lucas Tech to mix 50/50 stabilizer with the 80w-90w HD gear oil and it reduces the GL to acceptable levels for early differentials and gearboxes. Just did both my 32's.