Aoto Tranny Issues

hoorders · June 8, 2005

My 2000 Siverado 4x4 has recently developed a quirk. Its got an automatic tranny and Ive noticed that it intermitantly shifts quite hard into second gear. Doesn't do it all the time though.

Also, if I get heavy on the throttle, somewhere around 3000rpm and above, it will shutter for a second or two when it shifts into second and third gear.

Anyone else experienced this??

Could a tranny flush and fill with new fluid possible cure this?

Thanks for any help.

OUMike · June 8, 2005

A tranny cleaning and new fluids could help, but the thing about trannys is they should only be serivced if your done it regularly. I have a 94' with nearly 200k miles and I have no idea when the last time the tranny was serviced. Its better that I just let things run their course then to try to service it.

When a tranny gets 'neglected' that gunk and what not gets built up inside there. When you flush the tranny you risk knocking everything loose. I've had a few tranny shops tell me you could cut the life of your tranny in half by doing this.

Hope this helps

Mike G · June 8, 2005

This sounds like it would be the normal symptoms experienced under a TSB regarding harsh 1-2 upshifts. This occurs when the tranny is warmed up. Has there been any Check Engine Light activity. They can produce a code (DTC P1870) that will be stored. The correction is to replace the trans valve body, without possibly needing tranny overhaul.

--Mike

baswm · June 9, 2005

This sounds like it would be the normal symptoms experienced under a TSB regarding harsh 1-2 upshifts. This occurs when the tranny is warmed up. Has there been any Check Engine Light activity. They can produce a code (DTC P1870) that will be stored. The correction is to replace the trans valve body, without possibly needing tranny overhaul.

--Mike

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AAmoco Transmission want $550 to drill out the oval bore pattern and fit it with a steel sleeve and reuse original TCC assebly to fix problem.

quackmaster · June 9, 2005

I have the same problem with my 99 5.3L.

I have found one thing that I do that seems to help keep the hard shift from happening. It may sound silly and I'm not sure why it seems to work but it does for me.

-When you are accelerating from a stop or whatever and you know when your truck is about to shift out of first gear and make a hard change (the shift pt for my truck seems to be about 1900-2000 rpm) ever so slightly lift out of the throttle. Maybe lift your foot a 1/4" or so. Feel or hear the truck shift and then put your foot back into the gas as normal.

I don't know why this seems to work for my vehicle but maybe it will work for you. It makes me feel better when I don't feel or hear that hard shift. When I don't remember to get out of the throttle a little, I'm afraid I may hear alot worse noises.

hoorders · June 9, 2005

I have the same problem with my 99 5.3L.
I have found one thing that I do that seems to help keep the hard shift from happening. It may sound silly and I'm not sure why it seems to work but it does for me.

-When you are accelerating from a stop or whatever and you know when your truck is about to shift out of first gear and make a hard change (the shift pt for my truck seems to be about 1900-2000 rpm) ever so slightly lift out of the throttle. Maybe lift your foot a 1/4" or so. Feel or hear the truck shift and then put your foot back into the gas as normal.

I don't know why this seems to work for my vehicle but maybe it will work for you. It makes me feel better when I don't feel or hear that hard shift. When I don't remember to get out of the throttle a little, I'm afraid I may hear alot worse noises.

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Thanks for the reply.

Do you find if you keep on the throttle and the rpms up around 3500 that you get a shutter for a second or two once it shifts into second?

quackmaster · June 9, 2005

Yeah it will do that sometimes too. Kinda feels like it is starved for fuel for a split second or something. I also lift my foot off the acc. some for the other shift pts. Give it a try, let me know I'm not crazy.

hoorders · June 10, 2005

Yeah it will do that sometimes too. Kinda feels like it is starved for fuel for a split second or something. I also lift my foot off the acc. some for the other shift pts. Give it a try, let me know I'm not crazy.

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Easing off on the gas pedal at shift points does work..............but thats only because its taking the load off the tranny at the shift point.

Its kinda a hassel to be constantly adjusting the gas pedal to compensate for the tranny acting up and the other problem is, letting someone borrow the truck or drive it home after a night of a few cocktails.............other people who arent familiar with the shift points just let it shift hard into the gears cause they dont know any better.

I definately want to get to the bottom of the problem and fix it.

asilverblazer · June 10, 2005

Just a thought but if it is shifting quicker/firmer it is doing the same thing a shift kit would, reduce slippage and heat. That could prolong the life of some components. Just saying it may not all be bad.