Trans troubles

malibu
chevrolet
classic

#1

i rebuilt my turbo 350 transmission.i drove it about two blocks and checked my fluids.everything was fine.

so i drove it down town…two or three miles and i lost all gears forward and reverse.



i got a ride home and left the car for about three hours then i went back to get it.the transmission shifted fine as i drove it home.i have parked the car since i cant trust the trans not to break down.



as i drove to town i noticed a slight vibration in the trans area.


#2

sounds like you lost pressure - or it overheated?


#3

Hi,

When you say you “rebuilt” the TH-350, what did you replace? Clutch packs? Converter? Can you give more details? You’re saying it “vibrated”? Did you check the flexplate? Get the main pressure line checked and see if you’re in spec. All gears in forward or reverse indicate a massive pump / converter issue. Did it get hot? If so, does the fluid smell burnt? Did you drop the pan after the failure and see what’s inside? Signs of lots of metal or black material in the pan indicate failed clutch packs.

-Matt


#4

well i replaced all the clutches and the steel…plates?that go with the clutches.i replaced the torque converter seal and the driveshaft end seal.the flex plate is new only two months ago…maybe less i have no idea what main pressure line is…educate me please.

it did get hot before i rebuilt it…it was bad to the point there was no third gear clutches,only the metal disks were remaining.i did drop the pan a week before i rebuilt it and there was two handfulls of…fiberous material,fluid was black.i assumed this was third gear clutches.

the vibration was very slight…almost not there,that slight.i have not checked to see if a main cap on the driveshaft lost a needle yet…thats on my to do list.


#5

almost forgot to add i did replace one seal inside the trans…i believe it was in the second gear area…i had to remove a snap ring and a cap under the cap was 17 or 19 one inch long spring i removed the spring and the aluminum peice came out and the seal was on the aluminum part.


#6

I don’t mean any offense so try not to take any. But my basic impression based on your responses is that you don’t know how to rebuild a transmission. Its not the kind of thing where you can just buy a kit, take it apart and common-sense you way through it. So basically, your problem is going to be that you botched something, and I think that in the long run your best bet is just to take it to a pro who will need to tear it back down and make sure everything is on order. If you do this, don’t take it to a chain-type shop. Find your best local transmission shop.


#7

I agree with cigroller. You really have to know what you are doing before tackling an automatic transmission. Some people try to lead you to believe that you can just buy a book and do it like the pros but there is a lot more to it. The pros have developed little tricks of the trade things. Things that need to be done on a transmission when being rebuilt. Even the easier ones like the TH350. EVERY transmission has their own different things which NEED and HAVE to be done on them during a rebuild. Looking at what you said you did to yours, and if that is all you did, you actually didnt even do half of what needs to be done. Dont feel bad though. I know a lot of professional techs who are scared to even think about opening up an automatic transmission. Take it somewhere and have them fix it for you.

transman


#8

no offense taken.i am more than willing to say i know nothing.i did do a pressure test on it this morning.had to look up what ports i wanted and what pressure i needed.
looks like park,reverse,and nuetral gears are low in pressure and all the others are pretty close to what the site said they were to be.