Technical 3 Speed Gear Ratios

My original 3 speed ****** in my '51 Chevy has a 2:94 1st gear ratio.

My '51 now has a '59 3 speed O.D. ******, same 2:94 1st gear.

The ****** and bell are from a 1959 Impala, the engine is a 1961 235.

Is there a 3 speed out there that has a deeper 1st gear, with a ratio, in the 3: 00 + range ?

 

What ratio are the rear end gears? They should be like 4.11 or a little under [3.73] which would give you overall ratio 12.08 in 1st gear and 2.87 in 3rd OD..Lets say your rear tires are 27" diameter, that would give you 2507 rpm @ 70 mph with 4.11 gears..2256 rpm with 3.73 gears giving 2.61 overall in 3rd OD..

 

The 9" Ford rear is a 3:50 posi.
I either need to change the rear, which has already been addressed on another thread OR change the ******.
Are you aware of a Chevy 3 speed ****** with a 3:00 + 1st gear ratio ?

 

No, No such thing. My favorite combo is the medium gear set which has about 2.50 first gear and a 4.56 rear. Nice spread of gears to keep the rpm up plus a high gear for the highway. The wide set plus a 3.70 rear was standard with the OD.

 

You might be able to find a 7 bolt side cover Saginaw 3 speed with lower gears, and they would be quite a bit stronger than the old Muncie 318 transmission you currently have. A Saginaw with NO lines on the input shaft has a 2.85 first gear, 1.68 second, third is direct; 1 line is 2.43, second 1.50, and third direct; 2 lines is 3.11, second 1.84, and third direct, and lastly, 3 lines 3.50 first, 1.89 second, and third direct. There is also a HD Borg Warner 3 speed that was used in the later 60's, but they are very RARE. Saginaw is probably your best bet. I am Butch/56sedandelivery.

 

You may want to think about a BW T5.......unless you don't want a floor shift. The T5 was produced in a mul***ude of gear sets, depending on what application it was intended to serve. 1st gear all the way up to about 4.03 or such. Likewise, the OD ratios varied from low .70s or mid .80s. Look at www.britishV8.org for there excellent T5 application chart.

Ray

 

I currently have the BW 3 speed with OD in the car now. It came from a 1959 Chevy. I'm wanting to go deeper than the current 2:94, so some reasonable launch is achieved in 1st gear.
Right now, the 3:50 rear, with the 2:94 1st gear almost requires some clutch slipping, depending on road inclinations.

 

If possible, Ray, I want to stay with the 3 speed column.
It comes down to swapping out the Ford chunk, for a 3:70 or such, or swapping out the 3 speed for a deeper 1st gear.
I think the ****** would be less costly to do.
P.S. Ray, A great T5 info chart. Thanks.
http://www.britishv8.org/articles/borg-warner-t5-id-tags.htm

 

Typical OD cars had 4.11's in the mid 50's as I remember them especially 6cylinders and V8's had 3.70's. Without OD's 8's had 3.31's and 6's had 3.55's. I don't see a problem with 3.50's you have useless you feel your feathering the clutch too much or it's killing the engine when take off. Most final drives in the mid 50's was near 3.20-3.30 range and remember the speed limit was 55. Driving 70 now means buzzing it a little. With today's power everyone wants to see less than 2000 rpm at 70 mph. You need to choose what you want to do especially if your still running that 95 hp 216 6 cylinder. Good luck.

 

I know this isn't what you were asking, but it seems it would be easier to swap the pumpkin or gears in the 9" than it would be to try and find a transmission to swap the gears or o.d. to? I believe a 3.70 (9")gear set isn't too hard to find and likely can find a 4.10 or similar too.

 

The pic in the avatar is the engine. A slightly modified 1961 variety 235.
The 1959 Chevy had a 3:70 rear with the 235 engine and the 3 speed overdrive.
The 1959 Chevy had 14" tires, my '51 has the 15".
My 3 speed O.D. is out of a 1959 235 Chevy.
If I lost the O.D. ******, that would be fine.

 

FWIW, the 55-56 ford 6's w o/d came with 4:11's in a lot of cars and 4:27 Dana's in the wagon. 3.5's is more gear than most 6 cyl o/d's used. I think ford used a lot more od's than GM.

 

Cost is my primary concern.
Looking for 3:70 Ford gears, in a pumpkin, seems more expensive than trying to find another 3 speed stick, IF a 1sr gear ratio is even available in the 3:00+ ratio.

"Here is a quote from Tom Langdons stovebolt six page showing that what you are planning is just right, if you have not been to his site, it's worth a visit. He has been playing with the 6 bangers for a long, long time.

Gear Ratios
General guidelines would recommend about 12:1 1st gear overall driveline ratio (1st gear x axle ratio) for a good ‘take off’ gearing for a 235 Cu. In. engine. Below 10:1 will require clutch slipping and in excess of 15:1 will be an aggravation similar to a ‘granny gear’.

Final drive should be between 3.0 and 2.50. If overdrive is .73 and your axle is 3.73, your final drive will be 3.73 X .73 = 2.72 (perfect!)!

 

Bob, how about a VEGA 4-speed, with a 3.11 low? Modify your shift linkage to fit the ******, use an OD cable for reverse. Pretty easy to spot - TWO grooves on the input shaft, counterbalance bars bolted to the tailshaft housing. There was also a 3.50-low Sagnaw 4-speed, but I have NO idea of the app. Three grooves on the input shaft. I'm running the 3.11 behind my 235 / '57 Chevy, and LOVE the gear spacing!

I can't think or a rear-end with more ratios available than a 9"! Know of any stock car racers? If the rules allow, they ALL run 9" rears, so finding a pumpkin with 3.70's might be just a matter of asking a couple racers or checking around the pits after the races. You will need to put the spider gears back in, (as racers use a spool) or go with a limited-slip. Check the prices for a new R&P from Jeg's or Summit too - might be the easist way.

FYI - for every .10 change in gear ratio, engine speed will also change around 100 rpm - for the same road speed. That said, consider 4.11's with a 3-speed OD, if you can't find anything deeper than a 2.94 trannie. Lots of grunt on take-offs, easy crusing on the freeway. Good Luck, Tim

 

ALL of these older, 3 speed transmissions with OD have a Borg Warner overdrive unit attached to them, they are not Borg Warner transmissions, although one particular make (not GM) did use a Borg Warner transmission plus the Borg Warner OD. As far as the GM cars/trucks go, up until 66, they were a 4 bolt side cover, Muncie 318 transmission with a BW R-10 OD unit, and referred to as a 319 trans, after 66 they were Saginaw's with the R-10 OD; The Saginaw's were fully synchronized transmissions, and stronger. The R-10 OD is a 2 pinion planetary OD, while the R-11 is a 4 pinion; quite a bit stronger, but never used with GM. Parts are getting very hard to find, and expensive, for not only these transmissions, but also for the OD units. I am Butch/56sedandelivery.

 

How important is keeping the overdrive? If you do want the OD then the easiest answer is getting another 9" chuck set up with 3.90, or 4.11 gears. For long highway trips swap the 3.50 chuck back in. Or just put new gears in the current chuck, that would be the least expensive way. Maybe a little more if you pay someone to do the gear swap right.
-Dave

 

Tim, good to see you here, still remember your '57 from the calendar on C.T., several years ago.
If I had to go to a 4 speed, I would instead go to a T5.
I guess my answer is a three speed first gear is fixed at a 2:94 ratio, cannot get into a 3:00 + first gear ratio, with a 3 speed.

 

When the 3 speed trans with O.D. and bell housing was removed from the 1959 235 Impala, the glove box contained the 1959 Chevy owners manual plus a "Borg Warner 3 speed overdrive users manual".
From that manual, I was under the impression that the ****** was a B.W.

 

Yes Dave, I would like to keep the O.D., but the 3:50 rear ratio with the 2:94 first gear ratio in the trans. is on the ragged edge of slipping the clutch each time on takeoff.
A 3:70 or 3:89 chunk for the Ford 9" is expensive, in my world, thus the thought to get rid of the overdrive for a 3 speed with a 3:00 + fist gear, which does not seem to exist.

 

Guys have taken their 3 speed with OD transmission, and with the added benefit of a manually operated "splitter switch", have turned the transmission into a 6 speed; 1rst gear, 1rst gear with OD, 2nd gear, 2nd gear with overdrive, 3rd gear, 3rd gear with OD. Reverse has an over-ride, and remains a single speed no matter what you do. There are 2 Saginaw 3 speeds that come with first gear ratios of 3.11 and 3.50, and there are lots of Saginaws out there. Finding a Saginaw 3 speed with OD is the hard one, due to the fact they are used to make a Saginaw 4 speed with OD; the Saginaw 3 and 4 speeds share the SAME case and main-shaft, that's the reason the upgrade is possible, but even it involves some minor modifications.There are plans on the internet for making a Saginaw 4 speed with OD. I am Butch/56sedandelivery.

 

The next question is ..... what vehicle does the 3:11 or the 3:50 Saginaw fit ?
Will either of those Saginaws bolt up to the late model (1959) bellhousing, which is in the '51 ?
The O.D. is desireable, but not that important to me, in the overall picture.

 

i have been following this thread because i would like to put a lower gear in my ******. take offs on hills require i rev the motor . i am running 4.56 rear gears with 15" tires. 2nd is fine but not much higher than first.

 

Agree here... I am running a Saginaw 4 speed with the 3:11 first gear and a 3.73 rear end.
Nice combo with the exception of running ~2800 or so RMP's at 60MPH....
I don't do much interstate driving so it is fine with me..as far as strength, if you don't rev up and drop the clutch it is a fine transmission.

 

I have been doing some searching online, regarding the Saginaw.
I ran across a C.T. thread from 4 years ago, where you and DZ had differences of opinion, regarding the birth of the Saginaw.
DZ believed Saginaw began in 1955.
This chart would have helped your case.
http://www.drivetrain.com/parts_cat..._3_4_5_and_6_speeds_v24.html#GENERALMOTORS3SP

 

It's already a Corvette Muncie 318 transmission modified to a top shifter (Corvettes were geared a little better, and the Junior Stock guys used to use the Vette gears in the p***enger car case. That took some work to do. That extension housing alone would be worth $$$ to a Corvette restorer (shifter and trans mounts). As far as the 3.11 and 3.50 Saginaw first gear 3 speeds, I'd start with the 4 and 6 cylinder Chevy II/Nova's, and the Vega/Monza cl*** of compacts (probably pretty hard to find those any longer).
I am Butch/56sedandelivery.

 

If you are having difficulty off the line with 4:56 rear end, do you have a 2:20 or so first gear, in whatever your ****** may be ?

 

thanks, when you drive the car, first seams too high. this transmission was put together by my dad and uncle back in the late fifties. it uses a 37 chevy truck "shift tower" that was cut out and welded to the later chevy 3 speed. my dad remembers doing it but not the details of the parts used. my uncle has p***ed on since. my uncle may have swopped the first gears out. the cars won trophies at the track and these high first gears may have helped them pull away at the start [?] he told me side stepping the clutch at 3k was how he launched it, which may be fine for the track but take offs on the street, not so much, even with the low rear end gears. it was on my list to research a lower first this winter but i never got to it.
there is a scene in american graffiti were the little yellow coupe pulls out of the gas station after opening the exhaust caps and it appears that car was geared the same way.

 

i am going to check what gear i have. the car doesn't have difficulty but with the halves you would think it would be easy.

 

There was a Ford built 3 speed that various GM cars used in the mid 60's called a Dearborn 303, not sure if that refers to the first gear ratio or not. Pretty rare nowadays though.

 

I thought GM only used the Dearborn cl*** 3 speeds in 67-68 Pontiac Firebird/Lemans/GTO cars that needed a HD, full synchro, 3 speed transmission, and the Saginaw's just could't cut it. I've never seen one in an actual car, nor the Borg Warner HD 3 speed used in GM cars/trucks, that are also pretty rare. I still don't know how 3.11 or 3.50 Saginaw first gears can be beat for the gearing. I am Butch/56sedandelivery.