MTFCA Forum

Hi, I recently got my dads 1928 Chevy Doodlebug running/ driving after years of sitting. After some research I’ve come to find out that the rear axle is from a Ford Model TT. This was apparently pretty common in the tractor conversions due to the gear reduction. I can’t seem to find what type of modern gear oil I should be using for the worm gear differential. I know I need to flush and replace the fluid ASAP since its probably 40 plus years old! Any help is greatly appreciated.

Thanks!

That is a topic with some varied opinions.

My T's have Ruckstells, I use this:
https://www.modeltford.com/item/90W.aspx
It is expensive, but for me it lasts forever.

For a rear with no Ruckstell a heavier oil will work:
https://www.modeltford.com/item/140W.aspx
That stuff is right high too.

I think you will find Ford used what was called 600W, but I suspect it would be labeled differently today.

And about any modern day gear oil is probably better than what was used originally.

So you will find there are lots of preferences, but no one answer.

Some pictures would be nice.

And welcome to The Forum!

Thanks for the reply. Someone told me that most oils today are better than those back then. I had read that worm gears can cause more friction so I wanted to make sure I don’t do it any harm. I tried searching the forums but couldn’t find anything but since I just joined maybe I wasn’t looking in the right place. I have a link with photos below. I ordered a TT wheel puller so I can assess the brakes and replace the seals. Found out from a Chevy forum that the gas tank is a Model T with the fill neck relocated. My understanding is the transmission is a 4 speed 1 ton Chevy. It w ould be great if anyone here could identify any other parts.
Thanks!

https://www.dropbox.com/sh/baio6k8oxc6b ... RBcHa?dl=0

Except for the rear end and gas tank, everything else looks to be 1928 Chevrolet. Here are some links for parts suppliers etc;
https://www.fillingstation.com/
http://earlychevyparts.com/
Link to Vintage Chevrolet Club of America;
https://vccachat.org/
Specifications for the 1928 Chevrolet;
http://chevy.oldcarmanualproject.com/ch ... 8index.htm
The 600W would be correct. You can get it from Lang's, Snyder's, Mac's etc.

From left,

Lubriplate - correct for Ruckstells

M-533 - correct 600W for T rears

Cheap 80-90W gear oil - maybe as good as original?

Some say the modern oil can deteriorate the brass in the TT rear .


Love your hybrid doodlebug!

Thanks for the information and taking the time to reply!

OIL, -- you will get many opinions

Yes, most modern oils are better than those back in the day. Also we do not as high viscosity (thickness) as was needed back in the day due to technology improvements.

I run a 'non EP additive' 140 weight oil in my TT with a Ruckstell.
It is most important to use 'non EP' as the EP additive sits there quietly corroding any bronze components in the diff such as bushes and castings.

All the best and enjoy the bug! (ps, a picture would be great too when you get a chance)

Cheers,