Rear End Ratio for Terraplane

[Deleted User]

I just removed my differential in my 36 Terraplane, and found that I have a 4-5/9 ratio. I would like to find a 4-1/9 or even better, a 3-8/9 ring and pinion. I'm afraid that I will plug up the roads around here doing 45 MPH if I don't do something. An overdrive will just add expense and something else to work on, so I was hoping that someone out there has been through this before and has some suggestions. I don't want to put in a modern rear end. I understand that someone made some ring and pinion sets, but I have not had any luck in contacting them. I was told that the 8 bolt ring and pinion is interchangeable up to 47. Any thoughts?

Park_W

Scott, the 8-bolt configuration and the gear ratio indicate that someone has put that diff. in the car, from a '41 or later "factory overdrive" car. (8-bolt started in '38 or '39; the 4 5/9 ratio started in '41, I think). Anyway, 4 1/9 fiff. units are out there ... work the network and you'll fund one. The Railton folks in England have indeed had some 3 5/9 ring and pinion sets made, but they're pretty pricey ($800 or so.) But, if you want to drive the car for longer distance and at 65 mph, one of those gearsets might be worth it if your budget will allow.

Jon B

Scott, the fellow who is making the 3-5/9 ratio ring and pinions in England, is Pat McDonald. His address is listed in the latest H-E-T roster, page 90. The price will vary, in reference to the value of the US dollar versus the British Pound, of course.



Currently, he makes them only in the older 6-bolt design, but last time I spoke to him he was considering making them in the newer 8-bolt design.



I believe Ivan Zaremba is Pat's agent here in the States -- he's in the Roster as well, in California. But I'll check that and post my findings here, as soon as possible.



Don't bother to look for a 4-1/9 ratio rearend, it's still not good enough for highway travel, though it was the "factory" standard back in '36.

Unknown

You can slip most any Hudson rear under your car, Very easy by moving the spring perchs in approx 1.5" on each side. Most ideal would be a 51 hydro car. 3.58 ratio. Problem you will have is rear u-joint. 37 and up is diff. from 36 and earlier. I have been there , done that. I have a dana44 Hudson rear in my 1933 Terraplane 8. Fits perfect. Any other imfo. feel free to ask.

Geoff

'36 is same as later ones, with U-bolt type connection to the universal joint on the pinion. The 4-5/9 was an optional ratio for every year model. 3-8/9 and 3-5/9 were only supplied as replacements, never factory fitted. The 8 bolt pattern came in 1939, due to problems with the bolts shearing off in the 6 bolt version. Good luck.

Geoff.

Unknown

Geoff C., N.Z. wrote:

'36 is same as later ones, with U-bolt type connection to the universal joint on the pinion. The 4-5/9 was an optional ratio for every year model. 3-8/9 and 3-5/9 were only supplied as replacements, never factory fitted. The 8 bolt pattern came in 1939, due to problems with the bolts shearing off in the 6 bolt version. Good luck.

Geoff.

Geoff, Enlighten me. When did Hudson go from the flange type to the U-bolt rear universal? I thought it was in 1937.

Geoff

Flat flange used '32-'35 incl., U-bolt type from '36 on.

Geoff.

[Deleted User]

Happy Birthday Geoff!!!

Geoff

Gee thanks! How did you know??? Had a quiet day on my own. Loving wife deserted me for a day up North! Gnandkids rang from Oz though and sang "Happy birthday" over the phone!!

Unknown

Thanks. You the man.