Darrin gear oil

[warren]

What is the correct gear oil to use in the Darrin transmission  and rear axle?

[kaiserfrazerlibrary]

The Darrin Lubrication Chart is part of K-F Service Bulletin #416.  It shows SAE 80 weight gear oil for the 3-speed manual (with overdrive) gearbox, and SAE 90 weight gear oil in the differential.  It also notes about using SAE 90 if you are in hot climate areas.

Kaiser-Frazer or Willys never put out a regular Shop Manual on the Darrins.  KFOCI HANDBOOK has the complete set of K-F and K-W Service Bulletins issued on the car and can be used instead.  Note that the Service Bulletins indicate that for some issues, the 1951-1952-1953 Henry J Shop Manual is used for some mechanical issues, and the Willys Motors Mechanics Manual for the 685 and 226-6 engined Willys Cars is used for some engine and drivetrain issues.

I thought this was something the Darrin Registry handled for members?

[MarkH]

There's "GL (1/2/3/4/5?)" ratings if I remember right. Most important is one without additives that attack the bronze parts in the T-96. I'll check in my shop later what I used in my Aero & post it.  I think you have a HJ rear axle, lube as indicated above.

[MarkH]

Here's what I used:
Napa GL1 90 weight mineral oil. I had to buy a gallon, but there's also other sources. Be sure to fill the trans & overdrive separately.

I used Royal Purple 10/30w high zinc break-in oil on my engine & was getting an intermittent low pressure light. It was so thin on the dipstick I got spooked & changed it out to Lucas 30w high zinc break-in oil, & plumbed in a mechanical pressure gauge at the front oil gallery plug next to the fuel pump. Turns out I had good pressure & a bad NOS sender unit, but kept the gauge till permanent oil recently went in after 500mi.
I've never been a big fan of multi weight oil in older engines due to lower pressure in the past but decided to try this oil after researching viscosity ranges & comparing to their specs. Their 15/40 oil is running the same pressure full hot in 90 degree weather as the straight 30. Downside is it's 12qt boxes & $20 shipping. https://inrccca.org/product/classic-car-motor-oil/#:~:text=Classic%20Car%20Motor%20Oil%20has%20been%20designed%20to,the%20car%20is%20stored%20and%20not%20run%20frequently.

[Terry T]

use 30W for the engine with proper API' SJ or higher for good ZDDP content

[Terry T]

GL1 is a bargain at TSC