I was out hotroddin around yesterday and the ole' TH350 gave up! This is how it happened, got on the highway and manually shifted the car in to second. Took off down the highway and I couldnt get it to shift into 3rd, I only ran the RPMs up to 3500 to 4000. So I went down to the next exit and got off the interstate once the RPMs dropped low enough I shifted right into 3rd and rolled into the gas station. Stopped turned off the car got a little gas and thats where it stayed. Now it pulled off the highway and into the gas station in drive with no problem... I didnt know if anybody else had ever had this problem or if there might be a fix and not a replacement in my future?!? Thanks, Brandon
Ok, somebody else said to change the fluid and that they thought the govenor might have come apart. Is the governor external? Does it have its own cover, for inspection? Thanks again
New Fluid and filter, Cosmo's right probably clogged passages from old fluid or soft parts breakdown, if you like shifting it yourself you should consider putting a manual vavle body and a new shift kit in it, both relatively easy to do. Hard to kill a good turbo 350, I been 9.30's in the quarter at over 155mph and that trans is still in a ride around car now taking a daily beating.
Thanks Birdman, yeah hopefully fluid and a filter will be my fix. Nothing snapped and broke it just quit between startups...
The governor is under the large "cup" style cover on the side. Remove the clip, then the cover and slide out the governor. Inspect the nylon gear on the end for missing teeth. A friend had a similar situation happen to him. The plastic teeth on the governor stripped off, and he drove his vehicle VERY carefully !! The mechanic said they had probably gotten soft from age. He had a 1987 GMC pickup with only 37,000 miles...It was later stolen..from a CHURCH parking lot and never found.
Don't recall the governors themselves being much of a problem but it wasn't unheard of to see one with the nylon gear stripped of its teeth. GM used to service a gear kit for them and if they don't a good trans shop probably still does. But the governor doesn't really come into play untill the vehicle is moving, IIRC. It engages the output shaft and governor pressure increases as road speed increases. I think usually a failed governor gear resulted in a vehicle starting off OK in low gear but then refusing to upshift, assuming a stock automatic valve body and the shifter in drive. Governor pressure is how the trans senses road speed to determine shift timing. With a governor not working, even though you're moving in low gear, the trans "thinks" you're not moving because it sees no increase in governor pressure and sees no need to upshift. Governor pressure, working against throttle pressure (determined by the vacuum modulator and/or kickdown cable) determines if and when and how firmly the trans upshifts and downshifts. I'm not sure if any of these things would affect the trans going into gear when you drop it into drive. But they might have affected your initial "no upshift" condition.
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