'90 190E 2.6 trans problem

[samdon]

I have done an exhaustive search and find many references to 722.4 issues but most are for governor gear failures and lack of shifting between gears.

Mine seems to go into gear when I move the lever to Drive or Reverse but when I open the throttle it will rev for a second or two then jump forward. After that, it shifts perfectly. I've checked the fluid level per the manual and even went so far as to replace the filter and fluid. Same thing after the service. It seems to pull very, very weakly then catches fully and moves forward with normal power.

It seems to be getting progressively worse and I fear it will fail soon. Does this trans have the B2 piston which so often fails causing such issues or should I look elsewhere?

This is my wife's daily driver so I need to ensure its reliability as much as possible as soon as possible.

Sidenote: Similar symptoms struck our other 190E 2.6 about two years ago and I simply replaced the trans with a rebuild from Sun Valley. I would prefer to bypass that labor and just repair this one if possible.

Many thanks for your expertise and assistance.