The Stovebolt Site Forums The Shop Area Engine Shop 4spd A-833

Does anyone use this tranny. It makes sense seeing as how I am trying to get my 57 to drive 60 without running at 3000 rpms. I am keeping the original 235, and change the rear to a 3.73 or 3.55. As you may suspect, I got this info from "The Classic Chevy Truck" book, and now I want to ask you guys. It would be perfect for my truck. Thanks in advance.

Dodge transmission. You'll need to find the Chevrolet version, I don't recall what it's designation was right at the moment, but it was used in early '80s 1/2 tons. You may also want to consider the T-5, which will be much easier to find.

GM called there trans. the MY6.

If you find a MY6 trans.,be sure to get the shifter and shifter rods.Those two items are very exspensive parts by themselves.

MY6 is a drop in fit to replace a saganaw.

If you do not pull a trailer or haul heavy loads a T5 would be a good option.

I would go the MY6 way,if you can easily find one local.


Jimmy

I have one in my 63 C20 behind a 292. I haven't put that many miles on it, but like it. My mpg went from 12 to 16 on the highway.

The transmission was used by GM from 82-86 as RPO MY6. There were several versions of it. The early(?) version used a bellhousing with both the GM and Mopar bolt pattern, rare, hard to find. The later trans used the std bellhousing. They come in either a aluminum or cast case. I replaced an SM420 and it required the drive shaft to be shortened about 9 inches. The shifter comes up on the left side of the tunnel just in front of the seat. Fourth (OD) is just off the seat. When New Process added the OD to the trans they used 3rd gear. To make it look like fourth they flipped the shift lever on the fork up. Reverse is also different, left and up.

I would suggest that when you get one to get the shifter with it. In particular you want the MY6 shifter or one from a Dodge van. These shifters mount close to trans case on the tail shaft, and higher up.

Larry

Not exactly true. The transmission or the bellhousing will need machining to bolt together. The bellhousing of a 235 is indexed to 4.686 inches. The bearing retainer of the MY6 is 5.125 inches. To get the transmission to fit the bellhousing, either the bearing retainer has to be turned down to fit the bellhousing, or the bellhousing needs to be bored out to fit the bearing retainer.

Of course if you use the dodge version of this transmission, you can simply use a 1 inch adapter plate that goes from the chevy pattern to the dodge pattern. The Dodge version of this transmission has a pilot shaft that is 1 inch longer allowing for this unique conversion.

If the stock rear end is in good shape, there is no reason to change gear ratio. The 3.90 ratio will be like a 2.85:1 in overdrive. I wouldn't expect a mild 235 to be efficient or peppy with a higher ratio.

Thanks for the info. The book reads like I can use this tranny if I swap out a 23 spline shaft. But now I got all kinds of ideas. Thanks

Hi. I have a GM New Process A833 that will be going behind a 261 in my '49 Chevy 3/4-Ton pickup. I had the bearing retainer turned down like bidbadswingdaddy said, and so far, it bolts up great. The input shaft splines and shaft length are the same as the stock SM420. The only other difference is that the lower bolt holes are not the same size. I have 4.10 gears in the rear. Hopefully I will have everything put back together and roadworthy by Spring, 2010.

Thanks,
Dan M.