Transmission woes...

[SwitchBlade327]

We finally get around to improving the looks of my 59, and as soon as that's done the cruise-o-matic starts acting up...

Upon startup, it act like it doesn't want to shift out of first, play with the pedal a bit and it'll finally shift. After it gets warmed up, it'll shift out of first, but later and harder than usual. Most of the time, it only goes into second gear for about a second, then straight to third. Sometimes it stays in second for longer than normal and shifts hard into third.This is my ONLY car, so this is really annoying!

I checked the fluid and the level seemed ok, Gonna check it again after I pull into the garage where it's level. Outside of that is there anything else I should check? I need to limp it along until I can get my hands on a 390/C6 combo to stick in it...

[JohnG]

If you put the shift into D2 (which I believe means you only use 2nd and 3rd gear) is it just as bad??

Do you own a factory shop manual?? The chapters offer symptoms and possible causes (I am not near one as I type this or I would see what it says in your case)

john

[SwitchBlade327]

I do have a shop manual, but I keep at at work. Since I keep it at work, I have no time to look at it for my own car, and I never remember to bring it home so I can diagnose my own issues! Guess I"ll try to remember to look at it tomorrow...

[byersmtrco]

Sounds like an adjustment. Check the detent. Adj it out, see if it changes

[ncbird]

Wrecking yard

Switchblade, give Theodore Nine a call at Nine's autowrecking. They are in Granville county and tell him what you are looking for. He can keep his eyes open for you. My 390/C6 combo came out of a pickup and he gets some of the older stuff in. If he doesnt have it try Youngs that is where my 429 and 390 came from.

[tbird430]

If it is low on fluid try adding a can of Seafoam trans additive or B&M trick shift to top her off. Just make sure u have the e-brake on, the engine running, the car completely warmed up, and make sure she is sitting level when u check ur trans fluid.

After driving a few 100 miles, drop the pan and change the filter & pan gasket. Refill the trans back up with new fluid & drive.

I do agree you might just need a simple band adjustment in the end though....

[SwitchBlade327]

Ok, it's weird. On the way home from work today, it starting shifting normally again.
Were there any other transmission used in these cars other than cruise-o-matics? I'm wondering if it's something different, becuase I didn't find a vacuum line heading to the transmission for the modulator.

[byersmtrco]

An orig 1959-60 issue cruise-o-anchor did not have a modulator. Just manual detent (Throttle linkage)

Me thinks you had a servo stick and now it's freed up. Service the transmission, adjust (both) bands, and run some additive like Wynns conditioner. Keep the seals moist and things working freely.
Other n that . . . drive it !! Thats the best fix.

[SwitchBlade327]

The service manual mentions a modulator though? Or is that something different than what I'm thinking?

[bcomo]

As JohnG said, there is no vacuum modulator on a COM. What you may be talking about is the Shraeder valve that is on top of the engine near the bell housing. That is a pressure valve that's used as a final adjustment for the kickdown linkage pressure. I wouldn't mess with it at this point.

One of the first things that you need to check is the rubber grommet at the transmission shift lever under the car. Mine was just about gone. If that grommet is missing, or chewed up, the shift arm will not be in the right position no matter how much you adjust the linkage. You can get a replacement from Bird Nest if you need it.

Once you do that, the next step would be to chock the rear wheels, and disconnect the COM shift linkage at the connection to the steering column arm in the engine compartment. Next, lock the shift lever inside the car into LOW. Now, from the engine compartment, push the COM shift linkage to the rear as far as it will go -- the COM is now in low. Now adjust the nut on the COM shift linkage just untill it goes back into the hole on the steering column arm.

From inside the car, shift into park and start the car. Check that you have all gears, especially park.

Again -- none of this will matter unless that rubber grommet at the transmission shift lever is in good shape with NO slop.

Also, I agree with everything else said about doing a little maintenance on your COM. If you do change the trans fluid, you need to use Type F fluid since you don't know if the COM has been rebuilt using the new type fiber clutch and drum material. Mercron/Dexron fluid will cause the COM to slip if you use it with the old type clutch and drum material.

Hope this, along with the other advice, helps.

[tbird430]

Good point on the trans fluid Bart, that slipped my mind.

[SwitchBlade327]

Alright, so today it did the same thing as yesterday. It shifts weird for a little bit, then normally after I get about half way to work. I'm gonna try to do a fluid/filter change as soon as I can get it back on the lift at work, no idea when that'll be though. I need to put the new detent plate in the column as well...I'll just nurse it along until I can work on it again. I'm on the hunt for a 390/c6 though...

[byersmtrco]

Good point on the trans fluid Bart, that slipped my mind.

"Slipped" your mind??!! Good one !!!