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Discussion Starter · #1 ·
Just picked up a 66 Mustang. Planning on rebuilding the 2 Barrel autolite 2100 this weekend, and checking timing, upgrading to Pertronix.

But noticed something last weekend that scared me a little bit.
When you first start the car, the car will move itself into reverse. If you didn't have your foot on the brake after you started it, it would essentially drive away in reverse.

Seeing that I'm working on timing and carb adjustments, for safety reasons, I feel this will need to be corrected immediately.

FYI- The interior and glass is all out of the car as it was supposed to go to paint next week. So there is no "shifter handle/button". You sort of have to pull the cable end at the end of the shaft and move the shifter handle into desired gear. (Don't know if this would effect this or not)

Anyone got an idea where to start or have seen this before?
 

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Seems to be an adjustment issue, probably in the shifter linkage. Get under the car and loosen the nut on the linkage then manually throw the shift lever into park (pull backwards). This should be in the same spot that the spring loaded stop is sitting on the toothed ramp of the shift handle/lever in the car in the fully forward position (might have to remove bezel to see that, or just feel for it with the lever.

The neutral safety switch may also be to blame, since when properly adjusted, it should prevent you from starting the car in gear. It may be out of position, or possibly wired wrong. So your reverse lights work? I had an issue with a car once where the wires had been crosses from the neutral safety switch and the leads for the back up lights were engaged in park and neutral, the car would only start in reverse. Someone could have switched the plugs with the same effect, since the switch controls both functions.

Shouldn’t be a hard fix, but a fairly dangerous issue. You don’t want to trust the guys at the paint shop to know about that, so best to get it fixed before anyone else drives or starts it.
 

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64 1/2 D Code Coupe,
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FYI- The interior and glass is all out of the car as it was supposed to go to paint next week. So there is no "shifter handle/button". You sort of have to pull the cable end at the end of the shaft and move the shifter handle into desired gear. (Don't know if this would effect this or not)

Anyone got an idea where to start or have seen this before?
Did the problem exist before pulling the shifter out?
 

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Might just be as simple as needing to readjust the shifter linkage. It might say it's in Park on the shifter in the car but the lever on the side of the transmission might not be all the way in gear and the next gear for it to fall into would be reverse.

I just did this two days ago and it's pretty straightforward. The procedure's in the transmission section of the shop manual starting on page 7-24. The manual says to do the adjustments in order, so you have to adjust the gas pedal height, then the kickdown cable and finally the shifter linkage.

For the gas pedal and the kickdown you just have to turn the little adjuster nuts. For the linkage you loosen the nut on the shifter end of the linkage, hold the shifter in D (I used a bungie cord to the rear seatbelt) and manually put the transmission in D. Then you just tighten the nut back up.

If you have to you can then readjust the neutral safety switch.

Not much to it and hopefully that's all you need.
 

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Does the shifter move into reverse? If so, there is a little reverse lock out sprag on the shifter that may be worn or broken. If you do not have to push the button in on the side of the shifter to move through the gears, something is wrong with the sprag.
 

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Discussion Starter · #7 ·
Interior was completely out when I bought the car. It came with all new interior pieces.

Motor Mounts looked OKAY, I do have a drivers side long tube header rubbing the shock tower. Have not checked the trans mount.

Yes, the shifter moves into reverse.

The car is in PARK when starting. But as soon as it fires over, you can feel it kick itself into reverse. Let off the brake and it's rolling.

Again, There is no SHIFTER knob on the top of the shifter lever. Just the little cable ball end do dad. I don't know if that has an effect on this issue or not, preventing it from fully locking into Park/Reverse/N/D
 

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I don't know what the "little cable ball end" is. The stock shifter has a mechanical linkage to the transmission, so no cable except for the kickdown cable. Sounds like you may have an aftermarket shifter, maybe B&M. A photo would help a lot.
 

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Discussion Starter · #9 ·
I don't know what the "little cable ball end" is. The stock shifter has a mechanical linkage to the transmission, so no cable except for the kickdown cable. Sounds like you may have an aftermarket shifter, maybe B&M. A photo would help a lot.
I'll grab one this afternoon when I get home.
 

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I don't know what the "little cable ball end" is. The stock shifter has a mechanical linkage to the transmission, so no cable except for the kickdown cable. Sounds like you may have an aftermarket shifter, maybe B&M. A photo would help a lot.
Yes, but no. It is solid linkage to the transmission from the shifter, but there is a cable in the shifter itself that pulls the sprag up and out of the indexed plate in the shifter. As I recall there is a spring in the shift lever that pushes the sprag down. Either the sprag is broken, spring is broken or the cable is stuck in the up position allowing the shifter to move without pushing in the button. Absent the handle, at the very least, the OP should have to pull up on the cable to disengage the sprag and move the shifter out of park.

The attached shows the basic shifter:

https://www.cjponyparts.com/mustang-automatic-shift-lever-1965-1968-installation-instructions/a/488/

Picture 2 shows the little ball thing that is on top of the cable at the top of the shift lever. When the handle is on and the button is pushed this ball/cable is moved to the right, pulling up on the cable.

Picture 3 shows the sprag exiting the shift lever at the bottom right hand side and the vertical plate with the indexed stops for the shift locations.

The header rubbing the shock tower is very concerning. Hopefully it's motor mounts or a crappy set of headers vs the car having been hit.

Driver's side motor mount can be checked by starting the car with hood up. Put car in gear, foot firmly on the brake. Give it a little gas. The torque of the engine will raise the driver's side of the engine up a couple inches if the DS motor mount is broken.
 

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Discussion Starter · #12 ·
Alright Fellas, Yes I can move the shifter side to side a bit, about 3/8" wiggle.
FYI- The guy I bought this from, said he only "bolted everything together quickly" as parts were all over his shop to sell it.
Anyhow, here are some photos of the Ball Doo Dad, shifter, kickdown linkage (which looks totally wrong to me), and the adjustment bolt. Also, a video to show what I think the problem is. When the car is in park, and the "detent ball for the shifter button" is down, I can literally grab the shifter rod and shift it into reverse.
Let me know where and what I need to do, much appreciated. And, is there a better setup for the kickdown linkage? Seems like there's an awful lot of cable there for such a short distance.
SHIFTER
https://flic.kr/p/2hikQDN
SHIFTER BALL DO DAD DOWN (locked into position, cannot pull it into reverse/N/D, but it does click into reverse when I pull hard in Park)
https://flic.kr/p/2hikQE9
Shifter BALL DO DAD UP (can cycle through all of the gears)
https://flic.kr/p/2hij8Le
KICKDOWN LINKAGE (looks like it's looped the wrong way or something)
https://flic.kr/p/2hij8MB
SHIFTER ROD ADJUSTMENT BOLT (It's pretty far back on the shaft)
https://flic.kr/p/2hikQDT
ROD ON TRANS
https://flic.kr/p/2himSFC
I'm GUESSING THIS IS THE NSS, as it's disconnected and I can start the car in Reverse. So that's not good.
https://flic.kr/p/2him8eB

AND FINALLY, HERE'S A VIDEO OF THE SLOP/SHIFT.
 

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Ok, so it looks like you've got a few things going on. I've been staring at the transmission section of the shop manual for a week straight now so let's see if I can come up with something that makes any sense and might be useful.

1st, you've got the shifter plate for a car with a console. Doesn't matter today, but you might need to know that in the future. That dial indicator plate with the PRN0.L on it needs to come off though.

The shifter ball do-dad is just hooked to a little lever just under that plate. It's called the detent pawl and it slides along on a detent plate with different grooves cut into it like the side of a key. This is what keeps the transmission in gear and normally keeps you from just pulling it from P to R.
66-shifter.jpg

So you need to pull the plate off and get a look at it and make sure that it's sitting in the grooves properly and that it lifts up when you flip the shifter ball thing. You should be able to slide between some just fine, like D to N but you shouldn't be able to just pull it into R. Once you're looking at it you should be able to see how it works.


The kickdown looks like it has a lot of slack in it, but you need to jam the pedal down and see how it looks then. With the pedal on the floor that line should be tight and the kickdown lever pulled all the way forward.


I think the linkage bolt is fine if that's where it needs to be for the shifter to work properly. I think it's missing a washer to take up some of that play (and now I see that I think mine is too) but as long as it's in the adjustment range I think it's fine.


That wedge shaped piece on the side of the transmission where the kickdown linkage and the shifter rod attach is the NSS. Though that does look like it's wire hanging down on the other side of the transmission. Normally that wire should go forward and straight up the firewall to a connector hanging out just to the driver's side of the center of the car.

That's probably plenty for one post. Start by pulling that indicator plate off and looking at your detent pawl and you should be able to see what's letting it slide into Reverse from there.
 

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Simply said: There is a lever on the side of the transmission that determines what gear your car is in. THAT is what determines if you're in reverse. The lever inside your car is attached to that with a simple adjustable rod setup, so when you move the lever inside, the one on the transmission should mirror that movement. If the linkage is set too short, you could have the shift handle inside the car in "P", but the shift lever on the transmission only makes it up to "R", causing your problem.


The cable mechanism you mention on top of the shifter lifts a little metal plate that slips into detents in your shifter well, to help you 'lock' the shift lever into a gear, or prevent you from bumping into reverse on accident, etc. There's normally a "T" handle with a button you push to lift the locking plate, and allow you to move the shifter. With that button pressed, or the plate somehow disabled in order to shift gears freely, you will also feel the 'bumps' from your transmission's internal detents when you move the shifter.


To fix the adjustment problem, just chock your car, get under it, loosen the linkage and turn the shift select lever till it's 'for sure' in Park, make sure the lever inside the car also says Park, and then tighten it back up. If your bushings for the shifter inside your car are shot, those can also affect shifting, so it's a good idea to replace them. They're cheap, too.
 

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What I called the sprag the manual calls a pawl, so pawl it is. If the car will shift into reverse with the "ball do dad" down, the pawl is not properly engaging the detent plate. Remove that shift indicator panel and see what is going on. Since the pawl works to prevent some shifts it seems like it is a.) The shift linkage is improperly adjusted so that the shifter cannot go into park or b.) the detent plate is damaged to where the pawl can slide out of park.
 

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Discussion Starter · #16 ·
OK guys, FINAL UPDATE.
The plastic bushings in the shifter were replaced/greased. The shifter bushing underneath was replaced, and adjusted the shifter.

Everything is back to normal. Haven't had it jump into reverse at all, even with trying with force.
With that being said, always jack your rear if you're going to be letting these run. Just for safety's sake!

Thanks for all the help!
 
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