Worried about transmission...

[FRANKENTRUCK]

Since I got the truck back from the mechanic with a new distributor the carb has been sticking in high idle whenever I hit the gas to drive. If you hit the gas hard it idles (most of the way) down again. What has got me worried is this. I did not realize the high idle problem when I picked up the truck (nor did they tell me until I drove back there) and when I stopped the truck and put it into park then back into gear it jumped into gear. This happened about twice more before I was able to get out of high idle. Now when it idles most of the way down going from 1st to 2nd gear is not as smooth as it was before all this. It takes higher RPMs to get it to go to 2nd now (and it is not as seamless and smooth as before) so I fear I may have accidentally damaged the transmission. There is a little "JOLT" when it shifts now that was not there before, but I confess I have felt worse ones. My mechanic thinks the RPMs are still too high and this is why it is not shifting as smoothly as before. Any thoughts to help ease my mind? I just sunk a bunch of money onto this truck and will be ungovernably FURIOUS if the transmission is damaged.

 

[crazy4offroad]

Vacuum line for the modulator valve may be leaking. He could have done it when he was working on the distributor.

 

[Jims86]

Vacuum line for the modulator valve may be leaking. He could have done it when he was working on the distributor.

Yarp^^^^^what he said.

 

[Stroked]

Could the mechanical advance be sticking? I've had one do that before.

 

[crazy4offroad]

When there's a vacuum leak the carb will automatically actuate the choke, trying to restrict air and balance the air/fuel ratio. When actuating the choke, the linkage steps up on the high idle cam. I'm surprised you haven't noticed any light backfiring through the intake. Anyway, if the modulator valve isn't getting full vacuum it will shift funny. Also putting it in gear with the carb on high idle it will jerk pretty hard too. It's like holding the throttle open to 1500-2000 rpms and dropping it in drive, it WILL try to launch!

 

[FRANKENTRUCK]

Thanks for the replies. I intend to drive this truck 140 miles to the mechanic who put in the engine and transmission tomorrow. I hope it is safe to do this. Or if I could figure out about this leak I might be able to fix it myself.

 

[oneluckypops]

you can check to see if its leaking yourself real easilly. Just unhook the vacume line from the modular located on the transmission, if fluid runs out or it apears to be wet theres your leak. I would also follow that line back to the carberuarator the person who installed the distributor may have accidently unhooked or broke the vaccume hose.

But I wouldnt be too concerned about it idling high and having a jerk. Honestly I would be worried if it DIDNT jerk when the idle was high.

Fix the high idle and problem will go away

 

[HotRodPC]

Isn't this a 700r4??? No Vacuum Modulator if it is.

 

[oneluckypops]

Isn't this a 700r4??? No Vacuum Modulator if it is.

doah i assumed

 

[Jims86]

Isn't this a 700r4??? No Vacuum Modulator if it is.

Not till 82, unless somebody stuck one in there.

 

[HotRodPC]

I was thinking on another thread he said it had a 700r4. But, good reason to get more specifics. I'm usually the one that seems to ASS U ME all the time.

 

[oneluckypops]

I was thinking on another thread he said it had a 700r4. But, good reason to get more specifics. I'm usually the one that seems to ASS U ME all the time.

seems you have a good memory old dog

I had the original 6 cyl motor rebuilt, and it broke down on me during a trip. I called my mechanic to pick it up and the IDIOT (unknown to me) drove it home with a bad oil pump and FRIED the motor. (He is now FIRED). So after several years I bought this new 350 from Advance and a 700R4 transmission from a friend.

 

[FRANKENTRUCK]

This 700R4 transmission came out of a late 1980s Silverado and had to be converted from digital to mechanical to make my speedo work. So it may have a vacuum modulator.

 

[Jims86]

This 700R4 transmission came out of a late 1980s Silverado and had to be converted from digital to mechanical to make my speedo work. So it may have a vacuum modulator.

Nope, no vac modulator...how do you control lock up?