What vehicle, and what year? It's a giant leap backwards, but with enough time, money, and effort, it can be done. If you decide to dispose of the 4 speed, I want it! I might even be persuaded to trade you a 3 speed for it. No, I won't install it for you! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Really! Going with a 3 speed is a good anti theft gesture.
Craig
My '50 Chevy 3100 5 window, '62-235cu, 3:55 rear My truck ....... Respect The Rust If I'm not working on my truck, '65 m00stang or VW camper, I'm fishing with the wife or smoking Salmon.
Taking cues from the sparse information provided, a terse reply:
1965 and later Saginaw 3-speed transmission had synchronized first gear. It and the correct bell housing will fit the 235 but the transmission output is open drive (not torque tube). There are 1st gear ratio options but final gear is 1:1. This you need to know to work with your current rear axle ratio. To avoid calamity of a modified 3-on-the-tree setup, you would want a Hurst truck floor shifter, modified bracket and linkage. You have to make a new hole in floorboard.
Others will come along and give recommendations on the T5 5-speed transmission from an S10 but you specifically stated a 3 speed transmission of unknown year or make.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
I missed the crash box info. You can swap the bellhousing for a 1948-53 unit and use either the truck 3 speed or a SM-420 4 speed to get some of the gears synchronized. Swapping the crossmember at the cowling for a 1954-up item and converting to an open driveline and a different rear axle will give you more options on transmissions, including the T-5 which is a fully synchronized overdrive 5 speed. Basically, everything from the bellhousing on back will probably have to be swapped- - - -nothing is a direct bolt-in fit. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Taking cues from the sparse information provided, a terse reply:
1965 and later Saginaw 3-speed transmission had synchronized first gear. It and the correct bell housing will fit the 235 but the transmission output is open drive (not torque tube). There are 1st gear ratio options but final gear is 1:1. This you need to know to work with your current rear axle ratio. To avoid calamity of a modified 3-on-the-tree setup, you would want a Hurst truck floor shifter, modified bracket and linkage. You have to make a new hole in floorboard.
Others will come along and give recommendations on the T5 5-speed transmission from an S10 but you specifically stated a 3 speed transmission of unknown year or make.
. I apologize, but I clearly confused everyone. I am asking can I change the 1946 4spd for a 1946 3spd directly. I’m not asking about going to a more modern drive train. The current 1946 4spd with the “granny low” 1st gear is a total non-synchronized transmission….on all 4 gears. The 1946 era 3spd transmission is geared higher and is synchronized on 2nd and 3rd. I’m asking can I go to an original era 3spd without any modifications. Is it a direct fit?
Care taker of a 1946 1/2 ton. Pretty much period correct original. Danny T, from B’ham, Al
. I apologize, but I clearly confused everyone. I am asking can I change the 1946 4spd for a 1946 3spd directly. I’m not asking about going to a more modern drive train. The current 1946 4spd with the “granny low” 1st gear is a total non-synchronized transmission….on all 4 gears. The 1946 era 3spd transmission is geared higher and is synchronized on 2nd and 3rd. I’m asking can I go to an original era 3spd without any modifications. Is it a direct fit
Care taker of a 1946 1/2 ton. Pretty much period correct original. Danny T, from B’ham, Al
Spent a few minutes researching your clarified question using the resource provided for all at http://chevy.oldcarmanualproject.com/index.htm (all credit to them for sharing this valuable resource ).
Comparing the following pages from the 1941 Car and Truck Shop Manual (also covers through 1946 models as basically few changes during the war years), it does not appear that a truck 3 speed would be a direct bolt in for the truck 4 speed.
3 speed truck trans (with top mounted shifter/not car trans with side mounted shifter arms) diagram displays output is for a torque tube enclosed drive and 4 speed shows output for an open style drive shaft.
Just info found using the original shop manual (I have limited personal experience with this era of truck) and am sure that others with more direct knowledge will chime in to help answer your question.
Hope this helps the conversation along.
Dan
~ Dan 1951 Chevy 3 window 3100 Follow this story in the DITY Gallery "My Grandpa Carl's Truck and How it Became Mine" 1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver) US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)
The only modification will be to the pedal /master cylinder mount. Being that the four speed is wider, you will need to shim with washers between the mount and three speed to make up the difference. As you can see from this list they are the same length.
Wouldn't learning how to double clutch be easier??
~ John
A kid raised on Hotwheels, Matchbox and Tonka cannot be reasonably expected to own only one vehicle as an adult.
1949 Chevrolet 3804 In the Legacy Gallery | In the Gallery Forum 1973 IH 1310 Dump 1963 Kaiser M38A1 2001 International/AmTran RE3000 "Skoolie" 2014 Ford E-350 4x4 (Quigley)
I was needing to double clutch my 4-speed but I found that pausing in neutral for an instant while keeping the pedal depressed before completing the shift worked. No grinding. And since I'm depressing the pedal only once, my knee will last twice as long.
Last edited by Wally / Montana; 09/07/20222:49 PM.
34 Years. Now with a '61 261, 848 head, Rochester Monojet carb, SM420 4-speed, 4.10 rear, dual reservoir MC, Bendix up front, 235/85R16 tires, 12-volt w/alternator, electric wipers and a modern radio in the glove box.
I was needing to double clutch my 4-speed but I found that pausing in neutral for an instant while keeping the pedal depressed before completing the shift worked. No grinding. And since I'm depressing the pedal only once, my knee will last twice as long.
My 3 on tree is the same way. Alitta pause goes along way.
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