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going from closed drive shaft tras to saginaw overdrive. do i have to switch the side plates

Welcome to Stovebolt. To make it easier to answer you need to list what year and size of truck when you ask questions.

With closed driveshaft I'm assuming you have an AD truck with a column shifter and assuming the OD is mid '50s or later. Yes, you need to use your AD issue side plate and shifter arms.

yes i got a little ahead of myself. its a 1952,3100 column shift. iam installing a 65 or latter od.

wouldn't a Saginaw 3spd OD [1966+] be a different shaped cover? would a pre-54 side cover fit?

Bill

I have a 1967 Saginaw 3 speed overdrive. It has a 7 bolt cover. If you want to use your 3 speed on the column, you will have to modify the shift levers. If you have the original 216, it will have a tough time in overdrive. You need a little more displacement to realize the full advantage of an OD>

Not enough information here. He needs an open driveshaft for that transmission. That goes for the differential as well.

I disagree that a 216 will have a "..tough time in overdrive." The overdrive will provide extra gears to take advantage of the available power.

I agree the 216 will have a tough time in OD. My 248 is adequate on straight-aways but must be kicked into 'passing gear' on a lot of the hills around here.

the truck has a 235 and iam changing the rearend to 355 gear open drive shaft.the side plate is 4 bolt on both transmissions.

with a 3.55 rear an OD isn't much use unless the majority of your driving will be on flat highways .... and the Saginaw has a 7 bolt side cover, you have 66 or earlier Muncies, so no you don't have to switch the covers

Bill

Yeah, if you have a 3.55 gear in the rear end why bother with an overdrive???? Ya goona try for the Henderson County Speed Record?

That would be a set up where it probably won't be able to pull itself up a hill at 60 mph.

Denny Graham
Sandwich, IL

thanks for the help, ill let you know how it turns out.

The shifter arms on the side cover point in opposite directions on an AD truck. The arms point the same direction in a later truck. If you want the shifter to work right you should swap the covers.

Your first post says you have a Saginaw OD. Is this actually what you have? If so, it will have a 7 bolt shift cover. An OD transmission with a 3.90 is all your 235 will want. Cletis has a 248 with an OD and 3.90's and he will be the first to say that you don't want any faster gears. By the way, are you sure you have a 3.55 rear with an open drive shaft? Chev only used a 32-9 gear set in their passenger cars.

I was told it is a saginaw, but it has a 4 bolt shift cover. So what i read hear it is a muncie. The rearend is out of a 67 chevy truck.

Technically, it's neither a Saginaw or Muncie. Those terms as far as a transmission type were not used until the mid '60s (was told this by a Corvette transmission specialist). Having said that, your tranmsission could have been manufactured at either the Saginaw or Muncie plant. What you have is the SM318.

I have seen the SM318 with Borg-Warner OD referred to as SM319.

I've seen that, too, but them manuals I saw it in didn't specify it being an overdrive, but rather an updated version of the SM318. I beleive there was a change in the front retainer bearing perhaps? I'll have to get my manuals out and check sometime.

Alright, the manuals were a washout, all of them only referred to the 318. However, I did see on a transmission parts site listing the 318 as non-overdrive, and 319 as overdrive. Unless I find any different, it sounds good to me.

the SM319 was the OD variation of a 318, still referred to as the 318 by most folks - the early, non syncro 3 speed was a Muncie, and the later [post 66 or 67 or 68] all syncro 3 speed is a Saginaw [SM326], the OD for either was a Borg Warner add-on tail piece .... OD rebuild info .... all 3 trans' listed here

Bill

Until someone has different ideas, I will call mine with a 7 bolt cover a Saginaw simply because thats what I have heard them called for over 40 years. They actually resemble a T89 BW more than a Chevy transmission.

There is another '66-up full syncro 3 speed, the Muncie SM330. I don't know if it ever had an overdrive variant, though. It also has a 7 bolt side cover, same as the Saginaw, but has different ratios, with a lower first gear.

Well, I'm not sure what I have. It came out of a 67 Chev and has a casting# 3925647 and it doesn't show up anywhere in Hollander. I don't have any parts books for 1960 and up. Of course casting numbers don't do any good in parts books anyway.