Auto tranny wont auto

[1guydude]

My c6 in if i drive in drive...wont shift. I have to drop it down two more.to go in 1st and 2nd gear. I need third. Lol.
Is this my kickdown rod or maybe my vaccum modulator needs replacing? Plan on chaning at least the pan gasket and filter and fluid here soon
Thanks
D

[ThinLizzy13]

Sounds like the vacuum modulator. Make sure the vac line is ok before you replace it. You might get lucky.

[1guydude]

I have no speedo. Is it possible the tranny dosent know what the engine is doing. Like not hooked up right? Ill look into replacing.some.of the softer tubing and that vaccum
D

[ThinLizzy13]

I don't think the speedo cable plays a role in it. One thing to add is pull the vac line off the modulator - if trans fluid comes out the modulator is shot. If not then it's prolly the vac line.

[HIO Silver]

Do the obvious things first.... Check the fluid level? What about vacuum hose connections?

[1guydude]

I did manage to change a cpl hoses today. Carb to tranny vac and the lil fuel.one into the carb from the main fuel.line. Warmed the truck up. Tranny fluid looked over full hio silver.
It was a long day so ill check it again tomorrow.
Bottom hose was connected to the vaccum module. I didnt grab the hose or feel its condition or pull the hose and or module to see if fluid came out. I was wrapping up.
D

[colnago]

The speedo cable has nothing to do with shifting. The tranny spins a plastic gear from grooves on the output shaft. This drives a cable that goes directly to the speedo/odometer. No interaction with the engine.

Joseph

[1guydude]

Okay little update here. I pulled it all apart and the fluid was dark. Sludge in the bottom of the pan. Screen was clean. Changed gaskets. Screen. Fluid. Vaccum modulator was good.
So i changed the hose. Maybe ill change my vaccum module on my distributor...
When i went to put it all back together i tighten the linkage up a little so i could screw it in. That changed things.
Reverse is now all the way up. Than park 1 dwn. Than nuetral and drive. Which now acts like 2nd or 3rd gear and not 1st. Truck does shift better and do what i want as long as i dont go off whats on the steering coloum or floor shifter display.
Drive does not shift on its own.
D

[colnago]

If tightening the shift linkage changed things, I would disconnect the linkage altogether, and see how it drives. The PO on my truck removed the linkage when he installed an Edelbrock carb. Since all of my driving is in town, I've never bothered reinstalling it.

Joseph

[1guydude]

U want me to remove thr piece that connects my shifter to my tranny? The little throttle looking thing that screws in and unscrews? Its bolted to my pan with bolts and some spacers. I left the spacers out and tightened it down.
Ill try it .
D