mid 30's Chevrolet 1 1/2 ton rear axle ratios

[Brad in Wisconsin]

Hello all. I have an 1933 Chevrolet 1 1/2 ton truck. We all know they are not speed demons. But I used to drive a 31 Chevrolet 1 1/2 ton that was much quicker. Seems I remember that different ratios were available from Chevrolet at the time so if you were a dump truck ,over the road rig or a fire truck there were some ratios available. I do know of some rear axles from an 33 and a 32 lying about. is there a way to determine their ratios? maybe a casting number or the outside? Thanks

[BearsFan315]

this may help: https://www.gmheritagecenter.com/docs/gm-heritage-archive/vehicle-information-kits/Chevrolet-Trucks/1933-Chevrolet-Truck.pdf

 

and typically they did change rear end rations from year to year. i know from 1929-1932 the rear end ration on the passenger cars changed each year.

 

you could count the ring gear and pinion gear to get the ratio then divide them to get the rear end ratio!! the overall drive ration would depend on what the ratio of the transmission is.

[Brad in Wisconsin]

I dug about in the Chev. master parts book 29-41 and there seems to be 2 part numbers for the propeller shaft housing and differential carrier 364750 , 364538  with these three numbers after them 37 - 6 and 38 - 7. could those be ratios? I did see a note that the outer has a casting  of D or H for New Departure or Hyatt pinion bearings

[Bloo]

Probably. That is how gear ratios were specified in the parts book. Looks like 6.16 and 6.33.