1947 Steering Gear Lube

[Frank Starr]

What is the current product for steering gear lubricant?  The Shop Manual says GM 4673-M, but that deidn't make any friends at my local dealer.  They'd never had a request for manual steering gear lubricant.  Is there a NAPA substitute?

[Mike Josephic CLC #3877]

GM-4673M was used at least through 1955 or perhaps longer.  The generic equivalent is
90MP gear lube or more commonly known today it's 80W-90.  MP= Multi-Purpose

Mike

[Frank Starr]

Thanks, Mike. 

Would this be the same as 80 - 90 gearbox oil?

Frank

[Mike Josephic CLC #3877]

Yes -- same thing.

Mike

[John Washburn CLC 1067]

Folks,

Not to make an easy answer complected, but today the rebuilders I know use a partial mixture of grease and 90 weight in the manual gear boxes. Using 90 weight alone generally results in leaks in these old boxes. I have used the following with 10% 80-90 weight oil in my 37 LaSalle and 49 Cadillac.

Gear Box Lube

Auto Restorer, April 2004, page 8

Gm Steering box lube (sold by Zip Products at 800+962-9632 under part number SC-601) with excellent results.

I have also used modern CV joint lube, which is available from any auto parts store. The GM Steering box lube and CV joint lube both have the consistency of light grease, making them less prone to leak past questionable seals.

[Frank Starr]

Thanks, John.  I wondered about that.  In fact, I recently rebuilt an early (1955) Saginaw power steering box for a 1955 Studebaker Coupe (yes, it was original equipment back then).  After considering all the factors, I used CV joint lube in the gear side of the unit.  I think I'll do the same again on the 47 Cad.

[Mike Josephic CLC #3877]

Yes, I've heard about the leakage problem before.  The equivalent I gave you was from my old charts from Gulf Oil where I worked in the 60's.  That said, I'm sure that the CV joint grease
would work just fine in your steering gear box.

Mike