transmission problems

[12MPGHWY]

Car, 1981 300SD..

Ok so I changed the fluid and filter and took out the B2 piston to have a look. The B2 piston looked perfect, the fluid had lots of fine metal flakes in it stuck to the pan, and the filter also had fine metal flakes.

And the results are that trans problems are still present.

Here are the symptoms:

Car very quickly goes into drive or reverse (no delay, good)

accelerating from a stop in drive it seems like the car is starting out in second gear, and then at about 25-30 MPH it seems to shift back into first, of course the car is basically coasting at that point, and when it looses enough speed it goes back into second. If I push it up to about 4K rpm being careful not to over rev I feel it start to engage again.


If I start in "S" behavior is exactly the same as drive.

If I start in L, it seems to behave as it should, car stays in gear the whole time I think second gear?


What else can I look at before I start looking for a used trans?