Transmission problems

[spartus]

I currently own a GMC Sierra and when I leave my driveway and begin to accelerate it seems my transmission is trying to change gear, but my vehicle does not speed up. I can put the gas pedal down further, but still no response. My truck will do this for awhile, until the transmission cuts in and begins to accelerate. Also if I let go of the gas and reapply, my truck will accelerate fine. I have changed the plugs, fuel filter, air filter, transmission fluid and the PCM has been reprogrammed, but still the problem never goes away. Could this be a transmission problem or another problem.

spartus

[public]

What year is this truck. I have a late model GM car that did this. Turned out that the EGR valve is electronic and it had gone bad.

I usually do my own work and used to be ASE certified. I could not figure it out so I took it to a shop with a real good reputation. The mechanics at the local NAPA autocare center had it for a month and could not figure it out. Finally I decided to unplug componients one at a time so the car would go into limp mode. As soon as I test drove it with the EGR unpluged my original problem was gone. So I found one in a junk yard (new was $170) and installed. The car has been good as new since. Note that you cannot drive it without the EGR because it will be in limp mode and drive poorly.

Sorry so long. It just seems kinda strange so I thought I had better explain myself. Good Luck.

[INF3RN0666]

Your transmission WILL FAIL COMPLETELY in the next few days (Sorry to tell you that). Temporarely, you can get the car to accelerate normal if you put your gear selector into L (or 1), then when the truck starts moving, shift it into D.

I don't know the part name exactly but there's a "band" in the transmission that squeezes onto the axel. It has probably been destroyed somehow. I'm not much help but the point is that this is most likely mechanical. I wouldn't bother messing with the transmission if you don't have the tools to do so. Usually, if you can get the transmission open, you can clearly tell what's wrong with it.

My car has had its transmission replaced twice already, so I've experienced a few unusual moments.

[MagicRat]

Originally Posted by INF3RN0666

Your transmission WILL FAIL COMPLETELY in the next few days (Sorry to tell you that). Temporarely, you can get the car to accelerate normal if you put your gear selector into L (or 1), then when the truck starts moving, shift it into D.

I don't know the part name exactly but there's a "band" in the transmission that squeezes onto the axel. It has probably been destroyed somehow. I'm not much help but the point is that this is most likely mechanical. I wouldn't bother messing with the transmission if you don't have the tools to do so. Usually, if you can get the transmission open, you can clearly tell what's wrong with it.

My car has had its transmission replaced twice already, so I've experienced a few unusual moments.

The 'band' is part of a planetary gear set. It's function is to clamp down on the outer gear ring to stop its movement, which allows the 'planet' gears to rotate around the 'sun' gear.
All conventional auto transmissions use planetary gearsets, but not all use 'bands' As far as I know older Ford and older Chrysler transmissions use bands but GM transmissions do not have them.

[INF3RN0666]

Oh, sorry then, my post is useless. However, that problem has occured in a Cheverolet Impala 2000 V6 3.8L, which is under the great GM title :P.

[MagicRat]

Originally Posted by INF3RN0666

Oh, sorry then, my post is useless. However, that problem has occured in a Cheverolet Impala 2000 V6 3.8L, which is under the great GM title :P.

Hey, the key words were 'as far as I know'. Accept the free advice for what it is.
Still, I think that the repair shop was giving you a load of BS by blaming the bands on a GM car. You would not be the first person to have a transmission problem fixed by a relatively small repair, but charged a whopping big bill, since the mechanic can blame the 'bands' because we don't know any better.
I have not advised Spartus on his trans problem because it could be lots of things, from an improperly adjusted TV cable or throttle position sensor (depending on year) to a blocked fluid filter.

However, I do know that on a GM vehicle, it is not the bands.

[INF3RN0666]

I wasn't criticising your advice, but the car that had this problem was my dad's. The second thing is, why would the mechanic make up BS if he's paying the bill. The transmission is under warranty by that mechanic since it has been replaced with a new one.

[MagicRat]

Originally Posted by INF3RN0666

I wasn't criticising your advice, but the car that had this problem was my dad's. The second thing is, why would the mechanic make up BS if he's paying the bill. The transmission is under warranty by that mechanic since it has been replaced with a new one.

Well, thats a good question. Sometimes mechanics are not straightforward with people. Maybe they cannot be bothered with a proper explaination, maybe it was their own error that caused the problem in the first place and they don't want to admit it; who knows?

As I have worked with mechanics a lot over the years and some of them are truthful, some are not.

[01rollaS&accordv6]

does the tranny do it when its cold or hot if cold it is usually normal since the engine is trying to warm up if hot check the tranny. On gm trucks from what i know like my fathers sierra the computer and the egr valve went bad they (the dealer) told us the faulty computer caused failure and somehow caused the tranny to breakdown. just what i know i'm surprised i do not know this as i am certified auto-elec. i'm gonna find out wheni have a chance and hopefully let you know.