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3-speed to 3-speed/overdrive

T

The Pack Rat

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I have a '71 C-10 with a 3-speed manual and I would like to swap the trans for a 3-speed with overdrive. I found one for a really good deal, but it's from a '57 chevy and I'm not sure if it will fit. Would it fit my truck? If not, what years will fit?
 
just measure yours from mounting bolts to tail shaft ? then 55-58 style overdrive has a course tail shaft newer ones dont ? real differnce in the tail shaft need a course yoke for your drive line if you run early trans ? newer ones are a little beefer to !!!! running a v-8 with the early style you start poping the clutch and speed shifting them YOU WILL BREAK THEM !!!! the one your looking for came in like 68-70 trucks is called a T-85 i have one but overdrive dont work ? shifts fine had the trans in my 58 ? over drive wont lock in ? they are also all syncro where the old ones are not !!!! hope this helps !!!!!!!! doug
 
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step1958 said:
just measure yours from mounting bolts to tail shaft ? then 55-58 style overdrive has a course tail shaft newer ones dont ? real differnce in the tail shaft need a course yoke for your drive line if you run early trans ? newer ones are a little beefer to !!!! running a v-8 with the early style you start poping the clutch and speed shifting them YOU WILL BREAK THEM !!!! the one your looking for came in like 68-70 trucks is called a T-85 i have one but overdrive dont work ? shifts fine had the trans in my 58 ? over drive wont lock in ? they are also all syncro where the old ones are not !!!! hope this helps !!!!!!!! doug
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Thankyou so much. I didn't even think about what model it was.
 
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prior to 65 the saginaw 3 speed had a 4 bolt side cover and non synchro first gear vs the full synchro with 7 bolt side cover on the '65 and newer. the 65-69 1/2 ton trucks had the overdrive option and then they decided it wasn't feasible on the trucks. i hear some same vintage fords got the same basic unit and you can swap the heavier duty internals....atleast thats what my dad's buddy (big 57 chevy fan) told me, but i don't know about the later years. many of the od units were junked due to faulty solenoids that were rebuildable. i hear a company in mass manufactured the original solenoids but you'd have to buy from a third party as they are only recreated in bulk orders. anyway...thats a just a bit of overview off the top of my head. i plan to regear my 72 burb 3/4 ton from a 4.57 to a 4.10 and add the od unit to my 3OT so i drive it comfortably above 40mph.
 
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