Fluid change

[Motown 454]

Hi I have a 99 Tahoe it has 40,000 miles on it . I'm going to change the trans fluid. It has a little chatter going into overdrive once in great while on the highway. Any idea what causes this ? What do you guys think of the trans flush when you change fluid I'v heard it can give problems some times. I'm thinking of using synthetic.
Any opinions would be appreciated Wayne

[GetMore]

The only times I've heard of where changing fluid caused problems was when the fluid was over 100,000 miles old and the new fluid cleaned out the gunk and/or varnish the old fluid was leaving alone.
If you change the fluid regularly you should be fine. I don't expect any problems with doing a flush on your Tahoe.

Doing a flush is really the best way to go anyway. Just draining the fluid in the pan won't do much for you.

I don't think you should bother with synthetic fluid. Just have the transmission flushed every 30,000 miles or so, with regular fluid, and you should be fine.

I had asked Bowtie Overdrives about using synthetic in their transmissions, and they recommend using regular fluid and changing it periodically.

[Motown 454]

Thank You Wayne

[MonzaRacer]

Use the newer Dexron ,its Dex five i think. Its a synthetic and a direct replacement of the older fluid.
Also add a pan drain when you have pan down for filter service, I recommend draining and topping the new trans with lock up converters as the additives that stop the clutch shudder does "wear" out.
also if you just drop the pan you would need to have the trans flushed to get all the old fluid out and replace it with any type of fluid.
That can get expensive.
with the regualr service, then a tranny drain ever third or forth oil change keeps its clean and helps replenish the additives.
and every 3rd or 4th pan drain you can change the filter.
I have a fella who has a TCI trans and he drains the trans pan every other oild change(he goe 4500 miles at a change on his synthetic oil) and every 4th pan drain he changes the filter.
Oh and the engine and tranny has over 175k miles on it and he dragraces everyweekend too.