This is not a constant thing, it happens every once in a while, but when the car shifts, it will sort of shudder and buck during the shift. Any ideas as to what could be causing this?
2001 SS

 

Does it do this when you are driving around say...30 and up mph? It kind of feels like it doesn't shift where it is supposed to? If so mine is doing this same thing...no clicking or anything just does it every now and then

 

Is it only when the transmission is warm?

You could be starting to get the common 4t65e problems. A lot of time, the 1-2 or 3-4 shift solenoids start to go, or even the torque converter. It will seem like you give it gas and it bucks into gear. But it happens more when the transmission is warm because the fluid isn't as thick and you can feel the wear.

 

Mine does the same thing. 2005 LS with 89,000 miles on it. Every once in awhile, it has a hard shift from 1st to 2nd,2nd to 3rd, and not as noticeable into 4th gear. I've had the tranny fluid flushed and filled(due to tranny coolant lines needing to be replaced).FYI This is the 1st and final time the flush and fill will be done. It almost seems electronic in nature. It can be doing it, I go into the store(car gets turned off) and when I return it is working fine. Anyone have these issues with a solution?

 

I don't know much about the internal mechanics of the transmission, but I can tell you a few months ago my car would sort of hesitate, or take longer to shift into 2nd or 3rd, unless I really floored it, and that's not good for the transmission anyway. So I took it to the shop, spent $100 for them to flush the transmission and put new fluid in, (they used Dexron III, the cheapos) but the car shifted perfectly again, no hesitation, no studder, just nice clean shifts.

The owner's manual tells you that a tranny flush is not required until 80,000-100,000 miles, I think I'd recommend every 30,000 miles.

 

Yeah, I think I may need to just drop the pan, change the filter and replace fluid with Dexron 6. It was just done like 5,000 miles ago. But gotta be cheaper than tranny issues down the road. I'll give it a shot. I know I won't be able to change all of the fluid, but must be better than nothing. There aren't any issues with mixing 3 and 6 are there?

 

Way to go, Dexron 6 is much better for the transmission than Dexron 3, it's a bit more pricey but you're giving yourself more insurance on the transmission.

I honestly don't know if you can mix the two without doing damage, I would think that's a bad idea though. When you change the motor oil from the standard crude to synthetic you have to do a complete drain, so my instincts would tell me that you should do a complete flush.

 

http://www.valvoline.com/faqs/system...ssion-fluid/93

yes, it is ok to mix dexron VI and dexron III. i didn't think it would be either til i found some good info on valvoline's website. i found it helpful to browse around the other parts of their site also. however, being picky like i am, i would just have it flushed and put all dexron VI in, IMO.

 

Thanks guys. I might have to just take the plunge.

 

Well, I found out what the problem was.
First off, Yes, it was only when the engine was warm.
I took it to the local GM dealer for them to check it out, and they told me my valves for the transmission were bad. When it was cold shifting they worked fine, but once the car warmed up they starting working improperly.
Also, they found a lot of metal in the transmission, as in metal was decayed off and broke off.
The result: a 3,000 dollar brand new transmission.