73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 4x4orbust on August 30, 2010, 04:26:36 pm
-
hello everyone. i recently started driving my 82 again (passed inspection friday, Yipee!!!) and am having a little trouble with the tranny. i have tried searching, but don't know how to search for this issue.
when i come to a stop (at, say, a stop sign, or red light) the tranny does not shift down into first gear, it stays in second. it will shift into 1st if i put the gear selector into first. it will gear down if i "hammer down", but otherwise i take off in second gear. when coming to a stop it will gear down from 3rd to 2nd just fine. i remember someone else having this issue, but do not remember who or where to find it. any ideas on where to start? info is in my sig.
thanks!!
-
Adjust detent cable, check modulator adjustment, make sure governor valve isn't sticking.
-
what should the modulator be adjusted to? i would like the screw back to a factory setting, then adjust from there.
-
Modulators can be adjusted to compensate for engine manifold vacuum and/ or adjusted to control shift points. The factory settng would be point at which the shift points in MPH for your particular trans and rear end are met. Adjust, test drive, adjust etc,. How long did the truck sit prior to getting back on the road, and, did it shift correctly prior to putting it up? What if any work was done prior to the start in 2nd issue? Pull the vacuum hose off the modulator and make sure no fluid is in the hose or nipple. Are you sure the vacuum line is good (test)all the way to the manifold? On a different note, the troubleshooting chart (starts in 2nd gear, or slips in 2nd gear) points to the intermediate clutch or the intermediate clutch servo piston. Some intermediate clutch servo pistons are plastic and can crack.
-
i have gotten the truck to shift right from 1st to 2nd to 3rd by adjusting the modulator. i also reset the kick down cable to see if it helped the no shift down into 1st thing. it did not help.
the truck was sitting for ~5 years. it supposedly shifted fine before it was parked, as well as the tranny was rebuilt and only has about 5000 miles on it.
there is no fluid on the nipple of the modulator, or in the hose to the modulator. I have not replaced the vacuum hose yet, but will this weekend to eliminate that as a possibility.
I am going to bring the truck to a friend of mine who runs a tranny shop this week, hopefully he can diagnose and solve the problem. untill then, i am more than happy to try different things if you guys have any more suggestions??!!
thanks!!
-
Are you sure the detent cable is adjusted tight enough?
-
"i have gotten the truck to shift right from 1st to 2nd to 3rd by adjusting the modulator." << Contradicts >> i also reset the kick down cable to see if it helped the no shift down into 1st thing. it did not help." ??? ??? Are you saying there is no; full throttle 2-1 or 3-1 shift??? I'm not sure of the symptom your tryin to describe. Originally we were talking about a (in drive) starts in 2nd symptom.
9/14/2010 Ok I finally get it after looking at this again; "no shift down into 1st thing" = Starts in 2nd. ;) I see what your saying.
-
i apologize for the contradiction. when i come to a full stop, i have to manually shift the truck into 1st (on the column) for it to go into first. otherwise it will stay in second gear. after i manualy shift into 1st, it will (now) shift fine from 1st to 2n to 3rd. it will downshift fine from 3rd to 2nd when coming to a stop, but not into 1st.
also, it does kick down a gear when the pedal is "floored" (from 3rd to 2nd, or 2nd to 1st, but not from 3rd to 1st unless i am going under 20mph or so). i hope that clears it up a little.
i re-adjusted the kick down cable to see if it would make the truck shift down into 1st at a complete stop, which it did not. I adjusted as i thought was the right way. release the hold tab (not the metal button kind, but the plastic one you pull up to release the kick down cable adjuster thing) then get into the truck and put the gas pedal to the floor. then get out and push the lock tab back in.
i am not sure if it is tight enough, however i will try it again with someone else pushing the gas pedal and me sitting in the engine bay to ensure it did not slip back at all.
also, in reading my last post, i wrote "the tranny was rebuilt and only has about 5000 miles on it" the rebuild was done before the truck was parked for the 5 years. just wanted to clarify that, and the fact that i did not do the rebuild.
thanks
phil
-
make sure governor valve isn't sticking.
-
where is the governor valve located on the tranny?
thanks
-
http://www.dragracingonline.com/technical/vi_9-bm-3.html
-
thanks vile!! you always come through!! ;D
-
"also, it does kick down a gear when the pedal is "floored" (from 3rd to 2nd, or 2nd to 1st, but not from 3rd to 1st unless i am going under 20mph or so). i hope that clears it up a little."
Then the detent cable is doing what it's supposed to do, that's good.
"i re-adjusted the kick down cable to see if it would make the truck shift down into 1st at a complete stop, which it did not."
And it should not, the detent cable assists in delaying up shifts while at or near full throttle, or, assists/ forces full throttle down shifts.
Once you get done checking the govenor, we'll go from there... Govenor should be fine because you say it's shifting up through the gears. The govenor assists/ manages shift points.
-
If the governor valve is sticking/stuck Gov pressure will be high preventing the automatic downshift
-
If the govenor is sticking, there won't be any normal consistent up shifting.
However, if there are multiple issues with that tranny, you may be very well correct!!! So good to check the Govenor.
-
i stopped at my buddies transmission shop and had him take it out for a test drive. he said the same thing you guys are, that it is the governor valve. he tried real quick to get the cover off, but was worried about a piece of the case coming off with the cover and suggested i pb blaster it for a couple days to try and free it up. i have been spraying it, and will try a little harder to get it off tomorrow.
has anyone ever had a peice of the case crack or come off with the governor valve cover??
-
I might be eatin crow here!!! New Poll... ;D
-
got the cover off the governor, pulled it out, and it does seem to be sticking to me. the valve inside does not move when i push the "flappers" with the springs together. so a new one of them is in order. also have to get a new cover (bent the old one getting it off) and a new hold down spring thing ( bent that one too). but no chips came off the case when removing it!! did have to pull out the persuader and the BFScrewdriver.
tried to add a poll, but i think it's too late. it was gonna be:
whats my problem?
transmission doesnt shift down into 1st
transmission shifts from 1st to 2nd to 3rd fine
;D ;D ;D ;D
thanks again guys!! hoping the governor fixes the issue!
-
Just take that one apart and clean it. There's gotta be a piece of crud or varnish makin it stick. And before I took it apart, I would submerse it in solvent and work it real good to see if I could get it to free up. Then take a air gun and bluuuw it out real good.
The proper way to check it is to hold the govenor up side down by the gear, and moving the outer weights. The valve should move freely.
-
thanks fred and Ville for the suggestions here! huuuuuge help to say the least!
i brought the old governor to my buddy at the tranny shop, and he cleaned it out, got everything moving again, then gave me a NOS one to replace it with. ha ha!! also gave me a new cover and spring. threw them in/on and it now shifts just fine!! amazing, i thought it was going to be much more involved than that.
I now have to re-adjust the modulator because it seems to be shifting to soon. gonna play with it a little and see if it helps. otherwise it shifts down into first when i stop, and is much smoother shifting either up or down through the gears. hopefully it wasn't anything major that made it stick, but i'm gonna drive it and hope it doesnt happen again!!
you guys are the best!!
-
Glad to hear
-
Good Deal, looks like I get to eat the Crow....