can anyone tell me if a 4 speed tranny out of a 47 /48 one ton closed driveshaft will fit a 1/2 ton up to 53 i believe they went to open shafts in 54 right? you guys are the experts anyway what trucks will this tranny fit thanks for your help robert
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transmission
- Thread starter chev57
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Thunder54
Member
If the 53 already had a SM420 4 speed
You can simply change out the the closed shaft and open shaft parts if you have both trannies.
I found a real low mileage 1T 50 model 4 speed and replaced the the torque tube 4 speed in my 54 with it by switching out the back housings and U joints on the 2 trannies.
Otherwise, you will need to find a 1/2 T sm420 48-54 for the closed shaft application, but make sure you get the U joint, these are pricey.
Jim
You can simply change out the the closed shaft and open shaft parts if you have both trannies.
I found a real low mileage 1T 50 model 4 speed and replaced the the torque tube 4 speed in my 54 with it by switching out the back housings and U joints on the 2 trannies.
Otherwise, you will need to find a 1/2 T sm420 48-54 for the closed shaft application, but make sure you get the U joint, these are pricey.
Jim
maybe i got it wrong trans was pulled from truck that had a closed driveshaft maybe not a one ton i am trying to find out what it will fit .old truck has 8 hole wheels hood emblems on side say chevrolet 3600 looks like whats left of vin tag on door post was 6800# pounds but the numbers are rough door handles pull down so what year and size do you guys think it is vin started with5gr-h 1097 thats the best i could get can that trans be used in a 1/2 ton are they the same except for changes on driveshaft thanks for your help robert 
Kens 50 PU
Member
5GRH1097 translates to a 1949 3/4ton pickup built in August at the Kansas City, Missouri assembly plant.
8 lug wheels and the "3600" hood emblem further prove that it is a 3/4 ton truck.
8 lug wheels and the "3600" hood emblem further prove that it is a 3/4 ton truck.
Thunder54
Member
U joint
It will work, but you will need to acquire a 1/2T closed drive U joint. The 3/4T U joint will not work with the 1/2T drive line.
Jim
It will work, but you will need to acquire a 1/2T closed drive U joint. The 3/4T U joint will not work with the 1/2T drive line.
Jim
Scubanero
Member
info guys robert
It'll Work
Just look closely at the U-Joint splines . (count them)
GM used two different U-Joints on the same spline count ~one is light duty ,(3 speed 1/2T) and the other is heavy duty (4 speed apps) .
The tranny remains the same as the bigger trucks had a short enclosed forward driveshaft .
Now that I've enswered your qustion , may I be so bold as to request the left over speedo drive gear ? (the one on the side of the tranny the cable attaches to) .
Maybe the left over U-Joints & yokes etc. too.....
Just look closely at the U-Joint splines . (count them)
GM used two different U-Joints on the same spline count ~one is light duty ,(3 speed 1/2T) and the other is heavy duty (4 speed apps) .
The tranny remains the same as the bigger trucks had a short enclosed forward driveshaft .
Now that I've enswered your qustion , may I be so bold as to request the left over speedo drive gear ? (the one on the side of the tranny the cable attaches to) .
Maybe the left over U-Joints & yokes etc. too.....
late late reply
vwnate1 i am sorry i have not looked at this post since i thanked everyone above your post just seen it i hope you got the parts you needed we are still on hold on that one to many projects but none to get rid of at this time except 72 i am posting ad on again sorry i did not reply to you way back then
vwnate1 i am sorry i have not looked at this post since i thanked everyone above your post just seen it i hope you got the parts you needed we are still on hold on that one to many projects but none to get rid of at this time except 72 i am posting ad on again sorry i did not reply to you way back then