QuestionQUESTION: what does the under drive piston in the tranny do? The car has a harsh
downshift going into first only. I had to pull the valve body when I first got
the car because of a frozen selector shaft. The UD and OD pistons of course
fell out, but one of them had 2 springs. Which 1 has the 2 springs and which
hole is it?
thanks - doug
ANSWER: Hi Doug,
The underdrive and overdrive "accumulator" pistons may have one or two springs, dependning upon year and application, according to the '98 manual. The manual shows two springs for the underdrive accumulator and one spring for the overdrive accumulator, but that is no guarantee. You might get the answer from a dealer parts counter. The springs are supposed to be color-coded as well which might vary by year and application. The purpose of the accumulators is indeed to cushion the clutch application so you are correct in looking closely at those set-ups if your problem is harsh engagement/disengagement. But neither the '98 nor the '02 manuals are specific about how many springs of what color go in the two accumutors.
So again, I would check with the dealer parts counter.
Roland
---------- FOLLOW-UP ----------
QUESTION: So if you were on your back, with your head facing the back of the car, which
piston is which?
thanks for all your help, doug
AnswerHi Doug,
I'm glad to help, now that we sorted out the terminology.
The manual doesn't clearly show you a view from underneath the van with the transmission in place, but the drawing of those two accumulators shows there to be a large three digit number engraved in the case just below the accumulator holes ("631-1..."). If you see that, and read the number looking at it as you would normally read such a number, the accumulator holes are above and slightly to the left of the number, correct? From that vantage point the underdrive (two springs) is to the left, and the overdrive (one spring) is to the right (exactly above the "6"). Does that make sense?
Roland
