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Auto transmission stuck
#1
Help guys! 

My 71 mustang has a C6 auto transmission. Nine months ago I ramped her to do some maintenance work. I did a transmission flush (7L of ford ATF) and changed the filter. I put in a Transgo 67 1-2 shifter kit too, a new vacuum modulator, a shorter pin and turned the adjustment screw a few turns in. She stayed on the ramps as it was then very wet here and coming up to winter. I was also waiting for a new, correct style exhaust system from the USA which took a while. Fitted now. I then removed the shifter mechanism from the car to insert new bushes into the lever as the action was very sloppy. That's done too.

Problem though now is that she will only shift from Park to Reverse but that's it. Won't go into neutral or then drive. 

She fires up so can't be anything to do with the neutral safety switch I believe? And the shift kit, vac modulator and pin should only make a small change in the revs she changes gear at anyway? The shifter mechanism by itself is very smooth with no free play.

Thoughts anyone please! As far as I can remember I cycled the gears when I changed the transmission fluid and she has been dry stored in my barn since. I can't figure out why she won't go through the gears now.

Cheers

Andy
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#2
Guessing you didn't get the linkage and manual valve mated correctly when you did the shift kit and reinstalled the valve body. See pics 26, 27 & 28 of this article. They are not in order, so keep clicking through the photos.

https://www.hotrod.com/articles/install-...eId=994048


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#3
(05-18-2020, 11:39 AM)Hemikiller Wrote: Guessing you didn't get the linkage and manual valve mated correctly when you did the shift kit and reinstalled the valve body. See pics 26, 27 & 28 of this article. They are not in order, so keep clicking through the photos.

https://www.hotrod.com/articles/install-...eId=994048

Thanks Hemi.

Bugger, I followed all the instructions so was confident that I had swapped the springs etc over correctly and reassembled and reinstalled as I should have.

But it sounds like there is more to it than just that which was not included in the Transgo notes?

Cheers

Andy
  Reply
#4
(05-18-2020, 11:39 AM)Hemikiller Wrote: Guessing you didn't get the linkage and manual valve mated correctly when you did the shift kit and reinstalled the valve body. See pics 26, 27 & 28 of this article. They are not in order, so keep clicking through the photos.

https://www.hotrod.com/articles/install-...eId=994048

Just checked the dipstick (should have done it before) and there's less than one cm showing. I know it should only be about half way up the little holes when cold but sounds a little low? As she's still on ramps I can't run her up hot to check. Would you suggest I top up a little first?

Cheers again

Andy
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#5
I'd take it off the ramps to get it level. Not knowing the angle it's on, fluid is a lot harder to take out than to put in.

Just a thought, are you able to move the shifter to all positions, or is it stuck in Park/Reverse?


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#6
(05-18-2020, 02:31 PM)Hemikiller Wrote: I'd take it off the ramps to get it level. Not knowing the angle it's on, fluid is a lot harder to take out than to put in.

Just a thought, are you able to move the shifter to all positions, or is it stuck in Park/Reverse?

The car is level on the ramps. I won't top up, don't want to overfill but as I have to pull the pan again anyway......

The shifter will move from Park to Reverse, just about, but no further than that so no other positions.

I presume that I'd need to drop the valve body again to re-install?

Thought I'd done it correctly but guess I can't have. I know there's other causes for a stuck tranny but as I only removed the valve body to do the shift kit then I must have done something wrong when refitting it. I am quite sure that I replaced all the springs, balls, valves etc properly (took me long enough checking and rechecking) so won't take it to bits again.

Cheers Hemi

Andy
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#7
Yes, sounds like the internal linkage has an issue. Also check the column lock rod, if installed, that it's not binding on something.


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#8
Sure sounds like the valvebody and manual linkage not aligned right . Can be tricky if you've not done it before . Need to get the manual valve in right , also the kickdown needs to slot into position at the same time
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#9
(05-23-2020, 03:28 AM)Gregaust Wrote: Sure sounds like the valvebody and manual linkage not aligned right . Can be tricky if you've not done it before . Need to get the manual valve in right , also the kickdown needs to slot into position at the same time

I haven't done this before so guess I did stuff it up unfortunately. I presume the valve body will have to come out again then?
Cheers
Andy
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#10
Yes . Does the kickdown lever feel ok and spring back if moved ?

The valvebody will need to be loosened , then locate the selector.
On a C6 you can see up in therewith the pan off.

It can be tricky to get the valvebody in to line up both the manual valve and kickdown as the valvebody is located and bolts started
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