2001 Screw with 4R70W trans. 15K miles
When towing my boat 3900lbs up a grade, I accelerate to downshift from 3 to 2 or 2 to 1, the trans sounds like its going to downshift, but makes a bad shudder almost like a broken trans mount. It does it for a few seconds then downshifts.
It does not do this when not towing, nor when on level ground, in fact it downshifts perfectly without a load.

Any ideas? Should I change the fluid and filter, or just go right to the dealer.
Is this the torque converter shuddering violently?

 

Well, since no one jumped in to help, I solved the problem myself.

Thanks

 

I just saw your post and mine would shudder a bit on stopping and starting just before they replaced my trans, now it does not do it. What was wrong with yours?
Terry

 

Huh?

Jeez, man -- You posted specifically to Factory_Tech and then complain when everyone respected your privacy?

 

I have a similar issue that has occurred only about 3 times during dowshifting on a steep grade. Once with a boat in tow, twice without. It is a quick shudder and hesitation, then no more trouble. It occurs when going from 2 to 1 and lasts just a second on two. Otherwise I have no real complaints about my tranny. Any ideas or help out there? Thanks.

 

I'm sorry, I didn't see it sooner. I really don't work on 4R70s so I wouldn't have been much help anyhow.

G