I’m running the MY6-A833a overdrive transmission in my 49 suburban. It’s a GEM! Don’t confuse the NP440 with the MY6-A833a. This is a light duty unit and is very easy to install.

You can use the stock 47-53 bellhousing but you must turn down the front bearing retainer on the MY6-A833a for it to fit. After that it’s time to figure out your rear end driveline set up ect. The shifters are hard to find, but EBay is a great source. I don’t recall having issues between shorter or longer rods when searching. I got lucky?

Once I found a good shifter core I sent it out to Hurst and they rebuilt it. Well worth the price and it’s tight and accurate. The shifter location is further back than the stock SM420 location so you’ll need to cut a hole and plan accordingly for your shifter arm. I had one custom made to Sorda look like a SM420.

I highly recommend this upgrade and love having the overdrive.

~ Phillip
1949 GMC Suburban - 10 year project
1952 Pontiac Chieftain Convertible straight 8 hydramatic
1945 GMC half ton truck - Driver- Sold 9-15-25
1946 Chevy COE - SOLD 1-5-26 BUH BYE CHEVY!
1959 GMC Half ton long bed NAPCO