i just got a rebuilt C-4 from Shift Management. seems to me that the shift point are way off! 30 mph for 1-2, and havent got it into 3rd yet. putting it in 2nd when starting off seems to be alot better then just straight Drive. any ideas? should i call them up and tell them to send me another one? or is there something i can do myself?

Chris

 

anyone? valve body? modulator valve?????? bad tranny?

 

Under normal throttle for any automatic transmission..... first shift 12 - 15mph, second shift at 24 - 27mph.

 

Also they might have put a LONGER modulator pin in which will make the trans shift at later points.

 

thats what i was thinking, so maybe get a different modulator? it shifts fine using manual shift patern, just in drive it shifts way to high, for 1-2. 3k+ rmps before it shifts.

 

Do you know what year this transmission is?

 

well like i said its rebuilt(by shift management) but i believe i saw something about 73' on it before i put it in.

 

ok... well then you have 5 different colored pins for possibilities. Yellow, Red, Green, Blue, White. These are all push in style pins not screw in. These are part numbers for different modulators but these are old ones & the might have changed, but can be used to cross-reference to newer numbers. MO-48 (yellow), MO-24 (Red), MO-25 (Green or Blue or White). They may come with the pins but may not. So if they don't you might be going to the dealer for the colored pins OR salvage yard.

 

ok thanks, ill get started looking around i guess.

 

Unless I missed it nobody suggested checking for vacumn at the vacumn modulator. There should be manifold vacumn at the modulator. No vacumn = no upshift til maybe 30mph and very difficult to make 3rd gear.

 

that would be the problem, i had the wrong line hooked up, the tranny i pulled had two vacum lines, and i plugged one and hooked the other one up, swaped them and now its good to go.