So I was driving up the mountain on the way to school today and my tranny began to struggle. When it was time for it to downshift it seemed like it lost power and began skipping/lurching and wouldn't downshift. But if I put my foot down a bit it would downshift and be fine. It's always seem to shift fine otherwise, first time this has ever happened. It's the 4r70w, any ideas?..... Could 10 degree weather be the culprit?

 

Have you checked the fluid level or had it serviced ?

 

It was flushed at 180k now at 217k, and it's at the right level and looks bright red. It shifts very well other than what happened today, so I'm doubtful it's failing mechanically. Could it be some sensor that is causing this. I saw something about the tps on another post.

 

TPS is on your throttle body and it may need cleaned or replace.. but, if it were the problem I would think you would have other problems .. like stalling out.

 

sounds to me more like an engine misfire under load not a transmission problem. when it down shifted, took load off engine it cleared up.

 

If it was a misfire, do you know any of the common issues with the 302's that could cause it other than a regular tune up?

 

If it was a one time thing and then cleared up, it could possibly be water in the gas - possibly. Can't hurt to throw a little gas line antifreeze in the tank, or just methyl hydrate. It will absorb moisture and pull it through and burn it off. Worth a shot.

 

Gas line antifreeze is just alcohol, your gas already contains 10% methanol unless your one of the few still able to find real gasoline.

 

When I had a similar experience, thinking it was the transmission, it turned out to be the TFI. It is easy to replace with another and test drive to see if it solves the issue. I suspect one could be acquired from a local salvage yard.

HTH

 

This sounds right. My truck did the same thing before I did a partial 6 liter tune up with the new plugs, wires, cap and rotor, and coil. I noticed that the old plug boot for the rear passenger side cylinder had a huge crack in it and was probably causing a miss. Once I did the ignition upgrade and did the wider plug gap, it does fine on hills and shifts properly again.