The Stovebolt Site Forums The Shop Area General Truck Talk Fluid specs for my 1937 GMC/Chevy 1/2 ton

Hello, I'm looking for advice and recommendations for my restored truck. All fluids. Engine, transmission, differential, brake fluid, steering box and radiator coolant.

Coolant - standard "old fashioned" green ethylene glycol

Transmission - 90 weight mineral oil per Chevrolet shop manual (available from Tractor Supply listed as Ford Tractor Transmission Fluid)

Steering Box - John Deere Cornhead Grease

Engine - I use 20w -50 motor oil in my unrestored 216. If you're worried about the lack of ZDDP in modern oils, use this 15w-40 oil developed by the Classic Car Club of America with 1600ppm ZDDP specifically for flat tappet engines https://inrccca.org/product/classic-car-motor-oil/

Brake Fluid - DOT 3

TeW = Just to clarify, your previous posts were all about a 1937 GMC T14A. Is this a new addition to your stable, or are we still talking about the '37 GMC with a Chevy 216 transplant engine?

Otto's info is probably mostly correct, but is dependent on what your truck actually has for equipment (including any upgrades or changes from original equipment).

Let us know more details so we can better offer accurate advice.

Dan, yes my truck is a 37 gmc with a 46 216.5 chevy engine (rebuilt), brake master cyl. and 3 spd trans. Steering and differential are OEM. New aluminum radiator.

Thanks for clearing that up TeW.

I know it's not GMC specific, but this 1937 Chevrolet Owners Manual provides the back then lubrication requirements/specs that should be equivalent to your truck.

The one thing to acknowledge is that today's lubricants have different ratings/descriptions than those back in the day. I'll not try to describe all the ins and outs of that as there are already a lot of discussions on the topic, mostly in the Driveline forum.

Hopefully others will chime in here with some sage advice.

My '37 has a 1970 250 ci engine, I've been running 10w30 synthetic oil for 26 years now, no extra additives. The valve spring pressure is weak enough it doesn't need anything else.

The zinc additives for camshaft wear was raised when the the muscle cars started getting bigger camshafts sometime in the '60s, in the late '90s it was taken back out due to catalytic converters and emissions. The levels now in most over the counter oils is back where it was before the muscle car addition.
A stock factory built 216 has 16-20 lbs of valve spring pressure with the valve closed, and 38 to 44 lbs with the valve open. The extreme cams that need the added zinc additives has upwards of 300 lb springs with valves open.

You can also use the 90 weight mineral oil in the differential. My engine was compeletly redone about 31 years ago and I have always used straight 30 weight Castrol, non detergent, and I only change it once a year and at each oil change I add about 5 ounces of Risolone zinc additive. It is near impossible to find regular oil in the parts stores, so I buy it off Amazon, 6 quarts at a time.
Also when I was doing the initial restoration back then, I used Silicone DOT 5 brake fluid. I have had NO issues in all that time. Okay, it's a garage queen, goes in and out of an enclosed trailer, and sometimes gets driven on some country roads.
Later,
Glen

1938 Chevrolet half ton pickup

I use Valvoline 15w-40 diesel engine oil. No additives. I now have over 95,000 miles on the 1954 235 in my '46 truck. Engine was rebuilt in 1986. No oil consumption, no smoking. Gets driven about 3,000 miles a year.