Pretty sure this is an input sensor issue, as it's so intermittent, but here goes. After I first start the van if it's been sitting for a long time (overnight for example), one of three things will happen:

1: It will shift into second fine, then after I pull up to a stop sign or some other stop and stop too quickly, instead of downshifting to first properly, it will shift UP into third. Given the very low RPM's when this happens, it's a bit on the violent side and brings the van to a halt.

2: It will "fall out of gear". If I sit there at the stop for long enough (20 seconds usually), it then downshifts into first. If I manually apply gas for 2-4 seconds, it will also downshift and start moving. Once again, because of the conditions, both of these shifts are more violent than I would like. But they don't sound nor feel mechanically nasty, so that's good.

3: It downshifts fine on its own and nothing unusual happens.

It only will do condition 1 or 2 one time and then not again for the duration of the drive. There was a period where it did it repeatedly at every stop a few months ago after I changed the fluid the first time, but then it went back to being just once a day. It also hasn't done a "condition 2" for two months now. Just the 1st one.

This transmission has about 173,000 miles on it. Fluid was changed twice recently with Valvoline ATF+4. For as long as I've had the van there's been the occasional slip when shifting into fourth (and rarely third), and sometimes a "bump" shift down into first, but both only happen maybe 30% of the time, and they haven't gotten worse. I'm well aware it's getting near the end of its life, and I don't mind a rebuild, but I'd prefer to hold out as long as I can.

Any thoughts? Input and output shaft sensors are original. No check engine light, and the last code reading turned up nothing transmission related at all. Just some collision detection errors from the instrument cluster conking out from crap solders. I'll fix that myself eventually, but it doesn't seem to be related to this issue as it occurs very rarely, and a good slap of the dash fixes that.

 

From what I'm reading, you could have a O-ring seal on the filter is not seating and causing you to lose fluid pressure or loss of prime to the pump. But without seeing the problem, its only a guess.

 

Alright, I'll try having the filter changed and see if it goes away. Could it also be a clogged solenoid pack?

 

Nevermind, she's sadly going to the scrapyard. The timing cover pipe connector broke and it now doesn't hold coolant at all. Part is hard to find/expensive and the labor isn't something I'm capable of doing as it's extensive.