The Stovebolt Site Forums The Shop Area Driveline 1942 3/4 Ton Ring & Pinion Swap

I have completed installation of a 1984 T5, in my 1942 3/4 ton truck. It makes a helluva difference in drivability. However, I would still like to change the 4.56 ring & pinion out for a stock 1/2 ton 4.10 R&P ratio. Problem is I can't find any information anywhere (including part numbers) to tell me if the 1/2 ton 4.10 R&P will replace the OE 3/4 ton 4.56 R&P, without modifications. Since 1/2 ton was torque tube driveshaft, and the 3/4 ton is open driveshaft, I'm wondering if the R&P specs for diameter, length, seals, etc. is interchangeable between the 4.10 & the 4.56 R&P? Since it seems no one is making a 4.10 or 4.11 R&P for the 3/4 ton Art Deco trucks, I figured maybe an OE 1/2 ton set might work. Sure would appreciate any input from the experts, before I start spending any money. Thanks.

I swapped out the 4:56 pumpkin in my 53 3/4 ton 3600 to 4:11s bolt in swap, now if this works back to 1942 I don't have a clue. Measure the bolt pattern on your 3/4 ton rear and compare to 50s-60s trucks. IF you are in luck re. size and bolt pattern then you need to locate a late 60s 3/4 ton that came stock with an automatic trans (make sure it's 4:11).
If your truck has 6 lug hubs none of the above applies. This info is for 8 lug trucks.

BTW, I'm running a 6 lug truck rear end out of a 1966 Chev pickup in my 1946 half ton. Gears are 3:08 and lots more ratios can be found in these years.

Best of luck

No interchange between 1/2 ton & 3/4 ton

Thanks for your input. I was aware of the 55-62 pumpkin swap from the Tech Tip article listed in the Stovebolt files. I do have one of these carriers (3.90) from a 55 1/2 ton. Yes, it would bolt right in to my OE 42 housing. Unfortunately, so far, I haven't been able to find all of the bearings and gears needed to rebuild the 55 diff carrier that I have. I kinda figured that the 1/2 ton R&P would not fit my 3/4 ton diff, what with the OE difference between torque tube in the 1/2 ton, and open driveshaft in the 3/4 ton. I'm gonna keep looking for the parts to rebuild my 55 carrier. I don't want to give up my OE artillery wheels and 6 lug axle configuration, so swapping out the axle is not my first choice, unless someone can recommend a later model axle that will allow me to mount my OE 6 lug artillery wheels. Thanks again for your help.