Shifting hard in first gear from a stop

2005 Terraza with about 120k but posting here because there's a lot more uplanders, same vehicle.

I can be rolling along for 1, 5, 10, 500 miles, whatever and occasionally it after coming to a stop at a stop sign or red light, it will seemingly slam into gear when I take off. It seems to slip for a second and then BOOM, it goes into gear and gives me no issues when on the road at speed, passing, cruising, etc.

I took it to a mechanic, who flushed the fluid and changed the filter. He said there was some metal in the fluid, but not enough to concern him. There were no codes.

It didn't change anything. It's to the point where I need to figure out whether to fix it or bail. I need tires, but don't want to put them on if it's not going to make it. We've only owned it for 10,000 miles, so no previous reference as far as the problem.

Any help? Thanks in advance.

Does this happen from a dead stop, or let's say, you are coming to a stop because of a red light, but the light goes green BEFORE YOU COME TO A STOP, and then as you step on the gas you get a bucking sensation?

Does this happen from a dead stop, or let's say, you are coming to a stop because of a red light, but the light goes green BEFORE YOU COME TO A STOP, and then as you step on the gas you get a bucking sensation?

I've noticed mostly after coming to a COMPLETE stop, but there have been a couple times - whipping a U'y, specifically when it has happened without being at a dead stop.

Had the same problem with our 07 Uplander . That is pretty much how I explained it to the stealership...

3rd transmission in it now ... both times same exact problem .

All under warranty .. last one was 1000 km before the 160KM Warranty limit.

M

I have the same problem in our Montana. There is a piston in the transmission that has worn out...can't remember the name of it. The funny thing is, I can not replicate it when I manually drop it in 1st at a stop, then shift up once I get moving.

I am experiencing this exact issue with my 2007 Uplander with 165K miles on it. May only happen 1 out of 50 times, but always when taking off from a complete stop.

Someone mentioned a piston wore out in transmission, is this something that can be repaired/replaced without removing or overhauling the transmission?

Would any kind of additive loosen up a sticky part or help the situation?