[cornfieldcars]

Hey folks...I did some searching but still have a question. I'm building a 48 chevy p/u with a 355/th400. The tranny didn't want to shift out of 1st. I'm going to check the vacuum tonight to make sure that isn't the problem but I was wondering...I don't have the proper hookup for the kickdown so I just left it off completely. Would the fact that there isn't a connection at all affect the shifting? If I'm not going to use the kickdown should it be grounded? I'm hoping all I'm looking at is poor/no vacuum as far as the shifting goes. Thanks in advance for your help.

Barry

[richard stewart 3rd]

Hi,
If the modulator valve isn't the cause, check the governor it has a plastic gear on it that wares out & cause it not to shift.
Rich
If you don't hook up the detent you will need to manually shift it to second gear when you need more power to pass something

[cobalt327]

Originally Posted by richard stewart 3rd

Hi,
If the modulator valve isn't the cause, check the governor it has a plastic gear on it that wares out & cause it not to shift.
Rich

Dollar to a donut Richard is correct w/the governor gear. It'll stay in first, no matter what you do. It's an easy fix, fortunately. Just drive out a roll pin, and reverse to reinstall. Finding a new gear isn't hard, either. Most any tranny shop will have them. Prob. set you back <$20.00 TL, possibly less.

Remember to place a pan under the cover to catch any fluid. , you can reseal w/RTV if need be.

[tnsmith10]

Originally Posted by cornfieldcars

Hey folks...I did some searching but still have a question. I'm building a 48 chevy p/u with a 355/th400. The tranny didn't want to shift out of 1st. I'm going to check the vacuum tonight to make sure that isn't the problem but I was wondering...I don't have the proper hookup for the kickdown so I just left it off completely. Would the fact that there isn't a connection at all affect the shifting? If I'm not going to use the kickdown should it be grounded? I'm hoping all I'm looking at is poor/no vacuum as far as the shifting goes. Thanks in advance for your help.

Barry

as far as a no shift condition goes on a th400, it could also be because of a faulty kickdown solenoid, but just fyi, you can run the trans without the kickdown plugged in, it just wont have passing gear.
as far as it possibly being a modulator/no vacuum issue, the trans will still shift, just really late and firm. but normally its a govenor issue. either the valve is stuck, or the gear has been apple-cored. if the govenor is free and the gear ok, id suspect a bad kickdown solenoid. gl

[cornfieldcars]

I pulled the line off and I have vacuum. I started it up and took it up the road again just to check. I tried shifting manually and letting up on the gas and gunning it and it did shift into 2nd so I'm kind of leaning toward the modulator. They aren't expensive so I will probably get a new one regardless. I'll do some more experimenting tonight. Thanks.

Barry

[cornfieldcars]

Bought a new modulator yesterday and installed it lastnight. Truck shifts perfectly now!!! I love $14 fixes!!!!!!!!!!!!!!!!!!!!!!