c4 slipping in 2nd

[farmer13]

Hi,

So, I installed a rebuilt C4 in my 71 f-100 w/ 300cu. When it shifts from first to second it slips and revs a bit and second just feels soft. i'm assuming that it is the intermediate band on the drivers side. Is that correct? Also I wondering if I have to adjust the modulator? what is its function? and does it fine tune shifting? i've been driving it around town and I'm worried that I'm going to burn out the intermediate band.


any comments or suggestions?

thanks

[BobbyFord]

Did you adjust the band? Who rebuilt the trans?

[fordman]

the modulator times the shifts as to rpms of the engine.

[Aussie_1970]

Yes check you are getting vacuum to the modulator..ie the hoses are good and the modulator is in good shape.

[farmer13]

No I haven't adjusted the band yet. i need to get a smaller socket for my half inch torque wrench to do it. those things are small four sided. I only have bigger sockets in half inch drive.

Super shops in San Diego rebuilt it. i put a new modulator on it but haven't done any adjustments to it either. I will replace the vacuum hoses first, the one up by the carb feels too loose , then I'll give it a spin and see if I need to adjust the band.

thanks,

I check back in tues after I do it.

[BobbyFord]

The square adjustment bolt is 5/16".
For the front band (2nd gear, or intermediate) tighten to 10 ft. lbs., then back out 1 1/2 turns.
For the rear band (low/reverse) tighten to 10 ft. lbs., then back out 3 turns.