transmission fluid maybe ??

I have a 95 rodeo i bought in 98. Its and automatic. It had 75K miles and it now has 156K. I'm having some issues when in drive (or seems any gear) while the break is applied at lights or stops. Park and nuetral are ok. When stopped and in a gear it seems to shake a little. It almost seems like its trying to push itself forward still. While on the highway in drive around 40 to 50+ it shakes like crazy towards the back of the truck if applying gas. I think i have even smelt a burning like smell when getting out of vehicle. It seems to do this in cold weather, its about 10 degrees here for the high lately.

I changed the air filter about a week ago and noticed a loose screw around the connection of the air filter line (end of it) to the top of the engine. I also tightened the screw down. It seemed to fix things for a little while, but the symptoms are now back.

Is this a transmission issue or a transmission fluid issue? I read the rodeo manual a little about adding fluid and checking it. I do not fully understand where they want you to add fluid. Sounded from what they discribed that it was in the oil dipstick area. Doesn't sound right to me, but im far from a mechanic. It also sounded that you may add it under the car next to where you drain it. Of course they didn't help a guy with a picture of where to add the fluid. I'm the type of guy that needs pictures for everything if he intends to try it himself for the first time.

I have read some posts that say to not flush the transmission, becuase it will hurt it worse. It flushing a bad idea? Is driving it another day until beginning of next week when i could get it to my mechanic a bad idea at this point? Is this something i can easily fix myself by just adding fluid?

I'm thinking on this one.....the bucking has me baffled.

But for now, just so you know, there is no ATF fluid dipstick on this truck, the ATF fluid must be filled from underneith the truck, through the fill hole on the tranny pan.

I understand you purchased the truck in '98, have you done ANY ATF fluid swaps since your purchase? And, do you know of any that were done prior to your purchase?

If not, 156k miles is a LONG time on the original ATF fluid, whether or not this is the problem I'm not completely sure. But I would NOT, repeat do NOT flush this transmission....you are leagues ahead by dropping the tranny pan, installing a new filter/gasket and refilling with 5 qts of new fluid, then a few thousand miles later, do a drain/refill to get some more new ATF fluid in there.

If you could provide more maintenance history; i.e. last tuneup, last ATF fluid change, etc....that may help.