Do any of you guys know of a way to add an overdrive to an old GM manual tranny (saginaw or muncie)? I turn like 3000rpm going 70 on the highway and not only do I not think that's good for the engine but i'm pretty sure that doesn't help gas mileage either. I'm going to be going to college soon and I really wouldn't like to risk problems with running relatively high rpms on long trips too and from when I visit back home. Do you guys have any ideas? and no, I don't want to just stick a tremec in there. I want to use my original column shifter so it has to have the linkages on the side for an external shifter (like in a saginaw or muncie). I just want 1-4 on the column and I can make shifters on the floor for reverse and OD (that might be weird but it's just how I want to do it). This transmission would be absolutely perfect for what I need but they go for about $2500 by themselves (same price I actually paid FOR MY WHOLE CAR) so it's a little bit out of my price range. But it has the Overdrives like I need and it is a "rod transmission" I think is how it's called? (it has the linkages for it to be shifted via rods... So any ideas on how to not turn serious rpms while keeping the 3 on the tree setup would be great... Thanks guys... EDIT: actually is there a way I could get a tremec tranny and convert the built in shifter to work with the rods? I just wish I knew what it looked like under the shifter...
I know there are such animals as 3-speed manual transmissions with an overdrive unit (total of 4 gears so to speak). Look around for something mid '50s GM. I've heard they at least came in '55-'57 Chevys. Basically, it allows you to keep the 3 speed on the column, and gives you a cable operated overdrive. There's also an electrical sensor/canister mounted on them that keeps it locked in overdrive. Search around on Google for a bit; I know there's a thread about them on the H.A.M.B.
thanks for the suggestion. I think I found what you were talking about a bit back. Would this be it? By the way, would there be any way to modify a tremec shifter in a TKO 500 or 600 and fab up something to work with the linkages (and would a tremec TKO 500 or 600 even fit in an A-body buick like my special deluxe)? It's geared correctly since the first two levers are 1-2 and 3-4. Then I could have overdrive and reverse on the last lever coming through the floor pans. It's just a PITA because the shifter is internal in damn-near all (if not all) Tremecs and I've never seen one in person to know how it works. I'd just have to cut up the lever or cut part of the shift assembly on the tailhousing to get at it to fab up something to link it to my shifter. lemme know if you have any ideas... If you skip to 10:18 in this video, it's a good example of how the shifter works http://www.youtube.com/watch?v=aZVNb5FlsQY I'm determined to keep the shifter on the tree because I've never seen that in another buick ever and neither has my dad and he's had 5 or 6 68/69 A-body buicks (skylarks/GSs) since he was 16 and been around em forever. I've also gotten hella good at shifting on the tree :3gears: .
Well the rail pulls on 3 shifters for 1-2, 3-4, and OD-R. So couldn't I fabricate linkages and connect them to each shifter and then connect the linkages to my current setup? For the other suggestions... I don't want the speed muncies w/ overdrive because I need those 4 gears with my low HP engine... Also it wouldn't really be an "upgrade" per se except it would take off some weight since the saginaw is an iron case. I also saw the gear vendors under/overdrive and that's not really an option because used ones go for like $1500-2000 and new ones go for as much as I paid for the car...
Chevy passenger cars and 1/2 ton trucks had an overdrive option that used the same saginaw 3 speed that is in your Buick. It's pretty rare but they do exist. Years of production were from 1965 til I think 1968. A straight bolt in, even the same driveshaft. Maybe find one on ebay. My son put a 4 speed in his 250 six powered '67 Impala. A cool setup, but it made very little difference in the performace of the car. The original 3 speed was fine. Something to think about..... Steve weim55 Colorado
The only vehicle I know of with 4 on the tree was a Ford Van back in the '60s. Your best bet for good mileage boils down to three possibilities, if you want to keep it a stick (recommended for mileage on an old car): 1. SLOW DOWN. You want to go fast, it's going to cost you. 2. Put in an overdrive trans. That'll help. 3. Upshift early with your gas pedal held easy. Not quite the same thing as #1. You will get the best mileage and clutch life by releasing the clutch at near-idle speeds. You should be so easy on the throttle that you stall your engine every once in awhile because you weren't on the throttle hard enough when you let the clutch out. I know a guy who towed a trailer from Bakersfield to near LA with a broken differential ring gear because he had to get his family of 6 home. He made it by crawling home at low speed. This was a '56 Chevy wagon with a 265, and he regularly got 18+ MPG driving it (again, overdrive) without the trailer. I had a '69 Chevy Nova with a 250 CI six and a Powerglide that got 23 MPG on a regular basis. There were no racing starts when I got that kind of mileage. Though one time I DID holeshot a 4-speed Camaro at a light with it. Six cylinder doesn't always mean "dog".:bla: OK, option 4, "Mr Rich college kid"...I know I wasn't! You can put in an external overdrive kit that'll cost you some, but you'll have to lay some cold hard cash on the line. It'll bolt to the back of your trans, and require driveshaft shortening. It'll probably cost you more than slowing down, and more than you will gain in the time you will be using the car.
Saginaw three speed overdrive can be grafted onto a sagninaw four speed, gives you lots of gears. An overdrive four speed sold on Ebay recently for a little over $600. The overdrive three speed is hard to find. There are articles on the web about the conversion which requires swapping tailhousings and minor mods such as drilling a hole or two. Not sure if those "free wheel' in overdrive or not. It they do, it would be weird.
They shouldn't free-wheel in OD. I think that's why they have the externally mounted "electric can". So, an electric lock for the OD, and a cable to get it to go into overdrive.
If $1500 is too much and you want to maintain the column shift then you've eliminated anything you can do short of a rear gear change or taller rear tires. That's the long and the short of it.
