Transmission has an aluminum case, short output shaft and large bearing retainer. Case numbers C13303A, tail shaft C13386 1, build date is 1976. Is this an overdrive tranny? Can I change to a long tail shaft and use in a b-body?

If it's an OD trans you will need to use B body OD main shaft.

I have a couple of A833OD long tail shaft units. I need an A body one, maybe we can swap parts.

What is special about a Long shaft overdrive? I believe shaft is same whether OD or normal, and you just swap the gears over with new shaft and housing.

You are wrong. The shaft is different. The OD gear goes where 3rd gear goes, and that OD gear is much smaller than a 3rd gear is, so the shaft is smaller in that position.

PS to moparts, your website is the best, and infolinks SUCKS!

Thanks for the replys all, so does this decode as an OD? Any reasons not to do this swap? It’s going to live behind a mildly warmed up 440, no racing, just looking for better mileage for road trips.

I probably is one, but casting numbers are just that, casting numbers. It's the final machining that makes it what it is and makes the part number. Problem is the case is the same regardless of the gear set.

If it's a 76 then it should be an A833OD. If the shift levers are on , one points up, the other down. Obviously though, they can be swapped. Pic show OD shift lever setup.



Look for something like this to ID it, top number shows the VIN of the original vehicle, which should allow us to say for sure

Got the up/down shift levers.

Sniper, do you know if the OD long tail shaft has the shifter mount in the correct location for a 70’ b-body?

It is a NP833 O.D. to make sure mark the input shaft and front bearing retainer so you can count the rotations of the input shaft compared to the output shaft revolutions in both 3rd and 4the gears, in 3rd gear the input and output shafts should turn identical, in 4th gear it should make the output shaft rotate about 1/4 turn more on the out shaft compared to the input shaft
I've own a bunch of different NP833 tranny(body styles and years) including two of the A body size O.D. tranny which both had the smaller output shaft like the 904 trannys used
As fars a bolting it in and using in a B body you probably better of looking for another NP833 O.D. tranny out of a pick up and van the use the best parts out of both trannys with the pick up longer style output shaft and tail shaft housing so it will bolt in to your car.
I put one of those in my current street car, 1966 Dodge Coronet Deluxe two door sedan replacing the slant six and 3 speed on the tree with a 440, NP833 O.D. and a Dana 60 with 3:55 gears
BTW I have one of those pickup, van O.D. 833 tranny that is in excellent shape with the stock type Hurst shifter in the tranny and rear end parts forum for sale on this site with pictures of it and 3 other 833 trannys I'm selling

Ok makes sense. I guess when I did a few of these swaps I did transfer the whole shaft and gear assembly. We moved the over drive to a cast iron housing. One was used behind a hemi. so it is certainly capable.

If you are going to use the aluminum you need to ensure no cracks and that the cluster gear shaft hole are not rounded open. Also good thrust bearing surface. The bearing retainer is going to be big bearing, but the OD truck type is too large for normal B and E body Bell housings. So you may need to change that or machine it to the smaller size.

As far as tail housings the ones I have seen (truck) had the dual shifter mount so it could be used B or E body. Since they are post 70 transmissions the mounting pad is also correct for 70 up cars.

If you chose to move to a different housing you need to move reverse idler too. Slightly different cut it seems so everything moves to new housing.

But they work fine and we have club members that use them behind 440 6 pack cruise cars.