Technical School me on saginaw 4 speeds

I found a Saginaw 4 speed for a few hundred bucks so I took the gamble on it. The main casting number is 3925656 and it has a single groove input. I haven't opened it up to verify it has the 2.54 first yet. I know they aren't the strongest things in the world but I'd like to run it in my 57 with a mild-ish small block. I'm usually not very hard on parts when I drive so I'm sure it will last just fine, but what are the weak points on these Saginaws? Anything I can do to beef it up while it's on the bench? It'll be getting a Hurst shifter. It's not a race car, just a street hot rod. No slicks or anything.

 

Drive it like you own it, not like you stole it.

 

Trans will be fine as long as you DON'T beef up your right foot, if you know what I mean. Like greybeard said.

Pat

 

even a saginaw is worth that much now?!!

 

any working car 4 speed is worth money these days.

I put one in my 396 powered truck when I was 18, and it lasted about 6 months...but I was really hard on it. A friend put one in his 64 truck about the same time, then he put a big block in his truck, and he goes easy on it, transmission is still working fine 45 years later. So I agree that how you treat it is the most important thing you can do to "beef it up".

 

Skinny rear tires will be your friends.......

 

I go easy on stuff as far as shock loads. When they do break what generally goes in them? Stripped teeth? Bent forks? Burred syncros?

 

The one I grenaded looked like someone put a grenade in it. The reverse manual th400 went right back in. But that’s what you get with 650 hp big block in front of it with slicks. I figured the 10 bolt would have went first?

 

https://m.roadkillcustoms.com/transmission-gear-ratio-chart/
How many rings? 0,1,2,3?

 

he said one ring.

I just wore mine out, 2nd gear got the most abuse. Nothing broke.

 

Got a Complete Saginaw T10 setup , flywheel to shifter out of a 79 GM car in the classifieds ..wierd year......Sold as a T10 steel case...Lots of owners were pissed off when they realized it wasnt an aluminum case....Was behind a 350 CID.....smog motor....

 

You mean Borg Warner. Most likely from a Firechicken.

What’s the 1st gear ratio on it?

 

You don't have to take it apart to find ratio

 

I'm just thinking how the Mustang T5s are weak until you shim them to keep the gears from deflecting, then you can pull the front wheels on slicks with them... Maybe just set it up on the tight end of the specs and run a good high end oil in it.

 

Saginaw’s get a bad wrap because guy’s bolt up a unit designed for low horse power vehicles.

 

Aren't all the input gears the same no matter how many grooves? Guy said it had been gone through so who knows if things have been mismatched.

 

Came out of a Camaro..same as the same year corvette..GM has a real PR nightmare that year. with these units..not sure on the ratio,,i have to look up the numbers again..if i recall it has a low first gear....

 

I've had a Saginaw in my 38 Chevy since the 70's and it has never failed me...granted I don't abuse it for the most part although it has taken in a few 1/8 mile acceleration excursions

 

When mine let go, it was shock load from wheel hop, rear of the case broke out at the idler shaft.

 

Bought a '62 Catalina factory 3 speed 2dr sedan that had a Saginaw stuck in it. Always heard what a terrible trans they are, so I figured I might as well blow it up since I had a Muncie M-20 I'd had for years.
Pulled it onto some fresh blacktop, wound it up to about 4 grand & dumped the clutch. Tore the driver's side motor mount in half & broke both headpipes off at the manifolds ... trans was fine ....

 

I got really good at replacing Saginaws quickly when I ran one behind a decent 327 in a daily driver pickup years ago. At the time, they were about $100, so no big deal to abuse them. Anyway, I’m sure they are fine if you drive like you say you do.

 

Yep !
@SuperKONR it is a 2.54 1st gear [with a single groove input] 2nd is 1.80 3rd is 1.44 4th is 1.00

Close Ratio transmissions always have a higher torque rating than wide ratio transmissions.

 

if you don't trust the grooves, you can count turns of the input shaft for one turn of the output shaft, in each gear.

 

I never think of the simple solutions LOL

 

With a proper clutch in front of it and no wheelhop, a 2.54 Saginaw shouldn't give you any problems up to around 450hp. Not likely you have a proper clutch though, as the aftermarket typically starts out at around 2800lbs of clamp on an organic disc which is too much for a Saginaw. You could shim the pressure plate to reduce the clamp pressure, or you could install a clutchtamer to make the clutch's hit on the transmission adjustable from the driver's seat.

Grant

 

As stated above, wheel hop is the killer. My 57 usually breaks the spider gears or ring and pinion, haven't broken the Muncie. However, there is no crossmember for support under the transmission in a 57. This could be considered a weak link. I plan to put a big block in my 57 and when I do it'll have side motor mounts and a transmission cross member. Good luck

 

Or practice isometric knee action.

 

25 years ago, when I could get Saginaws for 50 bucks, I bought 5 to keep as spares for the one behind the 427 in my 59 El camino.I was fairly conservative on launch, but ran it hard. The 427 was pulled in 2015 for a conservative 327. I have one spare left., have replaced the carrier bearing in my 35 dollar driveshaft and destroyed the spider gears in my rearend, but am still running the same 50 dollar transmission.

 

Not to single you out here but having spare Saginaws', I get the feeling you understand the weakness of them, what was the attraction to them "back then", the Muncie four speed wasn't terribly expensive, I get it nowadays the way the Muncie has gotten crazy expensive.
The other thing is (I'm guessing), a new Hurst shifter for a Saginaw costs the same as one for a Muncie, I equate it to paying to have used tires mounted and balanced, same cost as new ones.
Even when I was younger changing transmissions on a regular basis wasn't terribly attractive, sure seemed like a way to ruin a good weekend.

 

I paid 125 for a Saginaw 4 speed in 1979, and 100 for a new Hurst shifter for it.