PRNDL! We have PRNDL again!

02Apr06

You might recall my mentioning that I was having an odd problem with the gear selector not moving fully into Park; the best I could do was Reverse, so my test runs of the engine were all done in Neutral.

I had changed over the bracket that the shifter cable attaches to from the TBI trans to the turbo trans so it matched the cable connected to the column. In the process, I mistakenly pulled up too hard on the manual valve shaft, disengaging the detent spring and making it impossible to shift anything.

Well this afternoon I finally directed my attention toward this and took the pan off the trans again. (This is the third time. First time was to try to repair the original mistake and also change the trans filter, second time was when I realized I hadn’t put the fibre gasket in place between the filter and the valve body. I’m getting good at R&Ring that pan.)

I dismantled the valve body from the transmission again to try to determine the problem. Trouble was, I could hit the Park detent no trouble at all with the valve body out. I played around with the manual valve itself, poring through the FSM, and from what I could tell I didn’t have it installed backward or anything.

I did a test reassembly, and discovered that the manual valve stem was protruding too far on the engine side of the case and limiting the movement of the selector through the detents.

Obviously, I was assembling something incorrectly, but without the benefit of a complete set of assembly diagrams (the FSM is a little weak on that, IMO), and never having seen it put together correctly, I was just guessing.

Well, I took the manual valve shaft off of the throttle valve shaft again at this point, trying to see if it had somehow gotten twisted or something. I concluded it hadn’t. Then I accidently put the thing back together CORRECTLY!

There is a tang on the stamping that engages the detent spring which actuates the manual valve stem. I had been placing it against the end of that valve stem, thinking that hydraulic pressure must keep it forced against the tang. In retrospect, that doesn’t make a lot of sense, but it’s how I had formed my mental image of how it must work.

Surprise, surprise, the tang goes in between two rings at the end of the valve stem!


Screwdriver points at correct location of tang in between “rings”. I had been placing
it “outside” the rings (would be to the left of the valve stem in this picture).

All of a sudden, the range of movement of the valve stem was now almost completely inside the valve body at the other side, and even better, the stem moved with each corresponding movement of the selector lever through the detents! Yep, once I saw it that way, it made perfect sense!

Now that I’ve reassembled the trans, I’ve got the gear selector moving through all of the detents it should, and the cable is magically in the correct adjustment. Amazing the difference once things are put together properly.. :-
Oh, well, one more little problem solved!

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