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Discussion Starter #1
Title should say it all. I have a recently rebuilt Cruise-o-matic transmission that is giving me a little bit of trouble. It shifts fine on acceleration and seems to run pretty smooth for the most part, however when I stop at a light it doesn't appear to kick down into first, I give it a little gas and it tried to accelerate, then it'll kick down and I'm good to go. If, when I stop, I put it in park then back in drive this issue doesn't occur.

Any suggestions?

Anyone ever mess with the adjustments on the Vacuum Modulator, I know there is a screw on it that you can adjust, I have no clue what way to go with it.

There doesn't appear to be a Vac leak in that line, however I plan on replacing it just to be safe.

Thanks,
-Zig
 

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Hello Ziggy,

In situations like these, I think you are on the right track with first determining if the vacuum modulator is out of adjustment or has the wrong spring rate (coloured band around body determines different spring rates internally).

If you have the '66 service manual, in the general section for transmission there is a table of modulator pressure (TV) ranges for different engine vacuum settings.

Here's my suggestion (take it with a grain of salt), buy if you do not have a decent 0-100 psi pressure gauge and connect to the TV port on the rear of the transmission. Then attach a hand vacuum pump with vac gauge to the modulator and with the engine running adjust the vacuum to the modulator according to the table in the book and read the results of the table. Note them down, try to adjust the modulator across the vacuum range and get the TV pressure results. If you can dial in at one end of the chart but loose linearity at the other end might have to try another colour band modulator and repeat.

If you get the results that match the table in the book, then I'd move onto a sticking valve in the valve body or possibly a warped (leaking) plate in the valve body.

But I'd start with the modulator first as it's easier than messing with that valve body. I've rebuilt an FMX (amalgamation of an FX and MX) and it's a pain getting that out and that was on a bench, never mind under the car.

OK my thoughts, hope that helps a bit.

Cheers
 

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Hi Ziggy,

Me again, I'm such an airhead. Granted it's been 25 years since I had my first car, which happened to be a '68 galaxie. But I just remembered I also had the same problem as you do. Now I had the little 302 engine, FMX trans and a light duty WER axle but since the FMX is similar to the FX/MX just sans one pump the problem was the governor valve sticking in the body (on the tail shaft). I was able to jack up the rear of the transmission (unbolt mount, remove prop shaft and speedo cable) slide it off then get to the governor housing and valve. I dressed the valve, put it back together and no more problems.

Just something else to consider.
 

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Like DesertXL mentioned it sounds like the governor is sticking. One way to ck it is after you pull up to a stop, put it in reverse and hit the gas pretty hard for a few feet. Stop the car, put it in drive and see if it takes off in first. If it does you know the governor is sticking and will need to be removed and ckd. If it's sticking because of dirt it will probably stick again until the whole trans is dirt free.
 

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Put a C6 in her! I just got mine done and I love it! I put the E4OD 1st and 2nd gears in the C6 and 2500 stall. Wow what difference. Off the line the 3.50 posi rear will take the car sideways if you want. Couldn't even spin the tire with my old cruisomatic. But for non performance expectations/cruising the cruiso is great. I'll put mine up for sale since it good.
 

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Discussion Starter #7
Ziggy,
Have you been able to check the governor out? Curious to see what is found.

Sent from my STV100-2 using Tapatalk
No, was going to this weekend , but I have to go to Denver sunday, so I probably wont have any time.

-Zig
 

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Discussion Starter #8
Hi Ziggy,

Me again, I'm such an airhead. Granted it's been 25 years since I had my first car, which happened to be a '68 galaxie. But I just remembered I also had the same problem as you do. Now I had the little 302 engine, FMX trans and a light duty WER axle but since the FMX is similar to the FX/MX just sans one pump the problem was the governor valve sticking in the body (on the tail shaft). I was able to jack up the rear of the transmission (unbolt mount, remove prop shaft and speedo cable) slide it off then get to the governor housing and valve. I dressed the valve, put it back together and no more problems.

Just something else to consider.
You were 100% correct! Valve was not smooth at all, cleaned it up until it would slide freely. I had planned on doing a write up on how to do it, but it's too much of a pain to keep up with pictures while laying under the car.

Thank you for your support!!

-Zig
 

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You were 100% correct! Valve was not smooth at all, cleaned it up until it would slide freely. I had planned on doing a write up on how to do it, but it's too much of a pain to keep up with pictures while laying under the car.

Thank you for your support!!

-Zig
I'm glad it was something relatively simple and easy.

Cheers.
 
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