Hard Shifting Issue

bravenrace · August 5, 2010

Hi All,

I have a 2000 Sierra 2500. Recently it's started to shift extremely hard under certain circumstances. It never does it when it's cold (the trans, not ambient), and it sometimes does it when it's warm. Anyone have an idea of what the problem might be?

Thanks,

Jim

rmck490 · August 5, 2010

Have scanned for trouble codes? Most transmission codes won't turn on the CEL. Take it to Autozone or O'Reillys. They'll do it for free. Having a code to post up here will get you better answers to your question.

zibzer · August 5, 2010

Hi All,
I have a 2000 Sierra 2500. Recently it's started to shift extremely hard under certain circumstances. It never does it when it's cold (the trans, not ambient), and it sometimes does it when it's warm. Anyone have an idea of what the problem might be?

Thanks,

Jim

Do you ever change the tranny fluid and filter? Neglecting this is the root of most problems in the transmission, as far as I know.

There is also a vacuum line that adjusts how "hard" it will shift. If this line comes plugged or loose or has a crack in it it will cause problems.. research this on google, should find you a solution.

bravenrace · August 5, 2010

Thanks. I didn't know it could have a trouble code without a light coming on. No, I haven't changed the trans fluid and filter. This is because I just bought the truck a month ago and hadn't yet had time. It has 118k on it, and I have no way of knowing how it was maintained before I bought it. I thought about changing the fluid and filter, but then it if something internal it will all have to be done again. If you guys think a simple fluid and filter change might correct the problem then I'll do it now.

I'll have the codes read and report back tomorrow. Thanks again.

tanked_darren · August 5, 2010

Thanks. I didn't know it could have a trouble code without a light coming on. No, I haven't changed the trans fluid and filter. This is because I just bought the truck a month ago and hadn't yet had time. It has 118k on it, and I have no way of knowing how it was maintained before I bought it. I thought about changing the fluid and filter, but then it if something internal it will all have to be done again. If you guys think a simple fluid and filter change might correct the problem then I'll do it now.
I'll have the codes read and report back tomorrow. Thanks again.

DEFINITLEY I would change the filter and fluid, my truck at 80,000km wasn't shifting like it was new and after I dropped the pan and changed the filter and fluid, and it was nice again. Although don't be mad if that doesn't help because if it's a 4L60E they don't last forever in thier stock form.

Don't be surprised at metal on the magnet if you do it yourself that is normal.

FYI I don't think GM recomends flushes, and find out if your truck has dexron 3 or 6 because if its 6 you have to use 6 in it.

redrabbit · August 5, 2010

I have something similar....its only between 1st and 2nd when its cold, then it goes away. Damn 4L60E's!!!

bravenrace · August 5, 2010

... Although don't be mad if that doesn't help because if it's a 4L60E they don't last forever in thier stock form.

Thanks for the information. Although it will be hard to not be mad. I just bought this truck and since then it seems like it wants to fall apart. All kinds of things have gone wrong with it that weren't present when I bought it.

Anyway, as far as the fluid goes, will the manual tell me which type to use?

rmck490 · August 5, 2010

Thanks. I didn't know it could have a trouble code without a light coming on. No, I haven't changed the trans fluid and filter. This is because I just bought the truck a month ago and hadn't yet had time. It has 118k on it, and I have no way of knowing how it was maintained before I bought it. I thought about changing the fluid and filter, but then it if something internal it will all have to be done again. If you guys think a simple fluid and filter change might correct the problem then I'll do it now.
I'll have the codes read and report back tomorrow. Thanks again.

Good advice with the filter and oil change. That may be all it takes but you won't know for sure without the codes read. A P1870 code (trans slippage) for instance will command max line pressure causing the hard shifts. You can get that code with bad fluids and filter or with something major going bad inside the trans. I can't remember if this code will turn on the CEL or not. A P0748 code (pressure control solenoid circuit) will not turn on the CEL but the tranny will stop the shift adapts causing some hard shifting. This one's electrical related and you may need to change out the solenoid while you are in the pan changing the filter. So, get some codes before you pull the pan like you said; you don't want to do it again.

dlewis1111 · August 5, 2010

... Although don't be mad if that doesn't help because if it's a 4L60E they don't last forever in thier stock form.

Thanks for the information. Although it will be hard to not be mad. I just bought this truck and since then it seems like it wants to fall apart. All kinds of things have gone wrong with it that weren't present when I bought it.

Anyway, as far as the fluid goes, will the manual tell me which type to use?

that and the dipstick too

99silverado22s · August 7, 2010

Drop pan and put in new filter and fluid. Dex3. I wouldnt worry too much about it though, you want your tranny to shift hard. If it shifts hard instead of sliding into gear it will last alot longer. More line pressure the better.

desrtrat · August 7, 2010

when was the last time the MAF was cleaned..some tranny issues can be directly linked to a dirty MAF..

good luck

bravenrace · August 16, 2010

Drop pan and put in new filter and fluid. Dex3. I wouldnt worry too much about it though, you want your tranny to shift hard. If it shifts hard instead of sliding into gear it will last alot longer. More line pressure the better.

This isn't just hard shifting, it's neck snapping hard shifting. I changed the filter and fluid and it's still doing it. One thing I found out is that it isn't a 4L60E trans, it's a 4L80E. Don't know if that makes any difference or not. I haven't yet had the codes read, but will now. Any other ideas? It doesn' t seem to happen until my trans warms up. When it's cold it shifts fine.