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67 Mustang Tranny Issues

 
mikew148
New User
Posts: 10
Joined: 07/13
Posted: 07/22/13 11:22 PM

My son has a 68 Mustang with a C4 transmission 3 speed auto. The transmission will no longer shift out of low gear. All of the gears are off in relation to the gear selector. On the selector - Neutral, Drive and 2nd are Drive (low gear and stays there), Reverse is Neutral. Park is park when it's all the up but it jumps into reverse early when the selector is moved back.

We thought it might be the intermediate band so we dropped the pan, filter and valve body and sure enough the band was broken. We replaced it with one of those old snap bands. Everything went in fine, adjusted it as the directions said to and.....same exact problem.

Is the tranny dead?  Confused  

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waynep712222
New User
Posts: 33
Joined: 05/13
Posted: 07/23/13 01:51 AM

before we go too far... please check the transmission vacuum modulator..  disconnect the tube at the intake..  apply vacuum with either a hand vacuum pump with a gauge.. or extend the tube with some vacuum hose and use your mouth to apply vacuum..  like drinking a thick shake..   you should NOT have any leaks at all between the tube and the modulator on the transmission.. if the transmission won't come out of low gear.. it could be a vacuum leak from the transmission modulator..

PS.. the transmission modulator HAS TO BE SUPPLIED vacuum with a steel tube.. for most of its length.. with short rubber sections at the end..  if somebody has replaced it with vacuum hose.. as the engine load changed.. the rubber hose expands and contracts and delays the actuation of the modulator diaphragm..

when there is a lack of vacuum to the modulator.. it will have only first gear.. if you goose it.. you might get second or third gear..

~~~~~~~~~~~~~~~~~~~~

other things it might be..

there is a small piston and spring under the TAB on the transmission filter.. if that gets left out.. i don't know what happens.. piston goes into the valve body first.. then the spring. then the filter..


floor shifter or one of the rare column shifters.???

column shifter has a bell crank that fits under the steering column and the plastic bushings go bad allowing too much slop.. and preventing full engagement of PARK..


floor shifters also wear out...   is it wobbly??  there are 4 mustang magazines here and at least 2 articles on the floor shifter repair...

there is another issue.. thats rare...  do you see the lever on the side of the transmission..   once in a great while...

the lever on the outside of the transmission will break its weld with the shift shaft thru the side of the case...

so the motion is not transfered thru the case...

i have found a few of these broken.. usually when the motor or transmission mounts have broken and the engine/transmission can jump around.. its either going to break the shifter bowl or the manual lever..

warning.. there are a bunch of different versions.. almost all have some kind of ford part number on them.

you will be able to tell if you reach up and grab the shift rod or the shift lever with the rod unhooked.. and count the clicks... lets see how many will you feel..  if you are in park..  you will feel.. R N D 2 L.. so thats 5 ...  there are 6 positions..

this is a much later ford transmission.. but you can see the detent plate... and the detent roller spring...

as you move the gear shifter.. the roller on the spring end rides up and down.. positioning the manual valve.. |.|==|=|===|= at the proper position in the valve body..

5R55spool

you might also want to air check the transmission...
http://www.youtube.com/watch?v=ucTqlOHhCxM

being that its a 67..  thats 45 years old.. and you know how to remove the valve body...

if you have a transmission parts supplier. you might want to pick up a recalibration kit for the valve body.. its like a shift kit.. but no drilling usually.. just new springs for the various pistons in the valve body...

this does take some forward thinking to change this.. professionals have trays to lay out all the pistons and springs in order..    you will also need a C4 gasket kit or C4 valve body gaskets.. you don't have to buy a complete overhaul kit to get a gasket set.. no matter what the people tell you..  the units are set up 66 to 69 and 70 to 81.. so please check the tag on the side of one of the servo covers...  or read the casting numbers on the main case.. not the servo covers or tail housing . the main case of the transmission..  

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waynep712222
New User
Posts: 33
Joined: 05/13
Posted: 07/23/13 02:08 AM

you can almost see the manual lever in this image.. it has the shifter rod on it and is behind the neutral safety switch..

Fordc4 Neutraleafetyswitch

655Mump 1101 16 Service F

setting the neutral safety switch.. IN NEUTRAL as i recall.. with a  pin thru the  layers of hole to align it..

Fordc4neutralsafetyswitchadjustment  

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mikew148
New User
Posts: 10
Joined: 07/13
Posted: 07/23/13 09:31 AM

So there be hope for this old tranny yet! Thanks for the response, I'll be heading over to his place later today with a printout of this information. I'm pretty sure the vacuum supply line is rubber in the engine compartment and then transitions to steel under the car before returning to rubber at the modulator. I'll definitely check that line and the vacuum first.

Thanks again - Mike  

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waynep712222
New User
Posts: 33
Joined: 05/13
Posted: 07/23/13 09:49 PM

two more articles.. you will want to bookmark


there are 4 or 5 more spread out in the magazines here..

http://www.mustangmonthly.com/techarticles/mump_1101_service_ford_mustang_c4_transmissions/viewall.html


http://www.mustangmonthly.com/techarticles/mump_0908_how_to_build_a_better_c4_transmission/viewall.html


let use know what happens...  

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mikew148
New User
Posts: 10
Joined: 07/13
Posted: 07/24/13 12:01 AM

Well, the vacuum line was rubber and had a leak at the lower connection. I replaced it with a steel line and the vacuum leak is gone.  Cool

The gear selector needed an adjustment and now things are lining up much better. The car idles better also. I'm sure the vacuum leak being fixed helped but the adjustment to the gear selector seems to have released a drag on the motor when it's in park. For the first time in a long time it sits there a purrs in park! That's the good news.....

The bad news is -

Finding reverse is a task, and when it does pop in it's normally pretty rough. And on occasion there's chatter/clicking noise when driving in reverse.

Also, when drive is selected, I get either 1st and second gear or it goes to high gear with a slow steady acceleration. Kick down is not operating properly.

It's drivable but it still has some issues.  

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waynep712222
New User
Posts: 33
Joined: 05/13
Posted: 07/24/13 08:58 PM

well.... time to identify the exact unit..


the reason i know that you need one of the repair/recalibration kits.. is the springs in the valve body break... my 70 ranchero 302 2v C4 8" with 370K miles.. needed a recalibration kit a while back..  it had the weirdest shift pattern... it would start out in second. drop to first then slip till third engaged.. so i drove it by manually shifting the gears for years..   there was nothing left of the clutches.. and yes.. i know...  but i tried and tried to get some time to work on it...

i could have it up on jack stands and ready to drop the pan.. and get called away..  i tried taking it to work...  my boss would always burry it over in the corner of the lot and park broken cars in front of mine..   he did that with my toyota...  i actually had to climb over car hoods to get to my car..   it was surrounded tighter than a wagon train protecting from indian attacks..

i did get revenge on him..  after another tech had driven his elcamino without oil and wiped the crank out..  i got it the crank machined to fit his block.. got it all together..  had it on the stand.. ready to test fire on the stand.. boss was asleep in a car with the door open.. i turned the stroker small block around to aim the open headers at the open door of the car he was sleeping in..  i let it rip... he jumped up.. bounced off the ceiling of the car.. arms and legs all going different directions..  it was funny to watch..  oh sorry.. were you asleep..   he thought the world was coming to an end.   nah.. it was just his nap coming to an end..  his nap had begun at 8 30 am. it was then 4 pm..


here are some descriptions on the valve body spring kits..


25930 C4 Transmission Shift Kit (All 1964 and early 1965 Mustang).
TRANSGO SK 4
PREVENTS soft 1-2 shifts, passing gear spin-up,
clutch chatter and soft 2-3 shift.
Comes with complete, easy to follow instructions.
This valve body kit is designed for installation installed during transmission rebuild.
There is NO GASKETS INCLUDED.  



25931 C4 Transmission shift kit 1965-66 (Except early 65 Mustang).
C4 Transmission shift kit
This valve body shift kit is designed for installation installed during transmission rebuild.
There is NO GASKETS INCLUDED.
Transgo Shift Kit SK L4  



25932 C4 Transmission shift kit 1967 (6 cylinder only).
Ford C4 Transmission shift kit 1967
Prevents soft 1-2 shifts, passing gear spin-up,
clutch chatter and soft 2-3 shift.
Comes with complete, easy to follow instructions.
This valve body kit is designed for installation installed during transmission rebuild.
There is NO GASKETS INCLUDED.  



25933 C4 Transmission shift kit 1967 V8'S & ALL 1968-69.
Ford C4 Transmission shift kit
Transgo SK 4SL
Prevents soft 1-2 shifts, passing gear spin-up,
clutch chatter and soft 2-3 shift. Comes with complete,
easy to follow instructions.
This valve body kit is designed for installation installed during transmission rebuild.
There is NO GASKETS INCLUDED.  
this is the picture of the kit contents for the SK 45L



25934 C4 Transmission Shift Kit 1970-72.
C4 Transmission Shift Kit 1970-72.
Transgo SK 4-71
CORRECTS, PREVENTS or REDUCES soft 1-2 shifts,
passing gear spin-up, clutch chatter and soft 1-2 shifts,
raises line pressure. Comes with complete, easy to follow instructions.
This valve body kit is designed for installation installed during transmission rebuild.
There is NO GASKETS INCLUDED.  



25936 C4 C5 Transmission Shift Kit 1973-ON.
Ford C4 C5 Transmission Shift Kit
Corrects, prevents or reduces no reverse when hot,
1-2 slide shift, soft 2-3 shift, 3-2 cutloose, 2nd band failure.
Comes with complete, easy to follow instructions.
This valve body kit is designed for installation installed during transmission rebuild.
There is NO GASKETS INCLUDED.  


there are kits that include the gaskets needed available also...


25932-1 C4 Transmission performance reprogramming kit 1967-69. (automatic shift).
Automatic shift. Heavy duty, towing and competition.
Comes with complete, easy to follow instructions.  



25932-2 C4 Transmission Performance Reprogramming Kit 1967-69 (Automatic shift).
Transgo 47-2 C4 Transmission Performance reprogramming kit 1967-69 (Automatic shift).
Competition and off road. Comes with complete, easy to follow instructions.  



25932-3 C4 Transmission Performance Reprogramming Kit 1967-69 (manual shift).
Converts back to automatic shift.
Comes with complete, easy to follow instructions.  



25934-2 C4 Transmission Performance Reprogramming Kit 1970-ON (40-2 Automatic Shift).
Competition, off road and pro-street use.
Comes with complete, easy to follow instructions.  


25934-3 C4 Transmission performance reprogramming kit 1970-ON (manual shift).  

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mikew148
New User
Posts: 10
Joined: 07/13
Posted: 07/25/13 02:37 PM

Perfect, I just ordered the kit. The car is actually a 68 Mustang (not 67 as originally posted)

Spoke with the supplier and they're shipping out the Transgo SK 4SL kit.

Hopefully this does the trick, I'll keep you posted.

Thanks again and nice job of effectively using an El Camino as an alarm clock! I'm getting a great visual on the bosses nap coming to an end!  Shocked  

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waynep712222
New User
Posts: 33
Joined: 05/13
Posted: 07/26/13 10:30 PM

this is an EXCELLENT video on how to tell ford C4 valve bodies apart..

worth watching and bookmarking..

http://www.youtube.com/watch?v=yRgTEF5vP1o


there are several more videos there on teardown of the various C4 valve bodies..

hope you get this...  

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mikew148
New User
Posts: 10
Joined: 07/13
Posted: 08/10/13 04:38 PM

Well, the shift kit has been installed and all is good except we have no DRIVE gear. Everything else is lining up perfectly. From Park down to low all gears engage fine. When I put it in Drive it stays in 2nd gear and will not shift into drive. The kickdown is not working either.  Confused  

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waynep712222
New User
Posts: 33
Joined: 05/13
Posted: 08/12/13 07:38 PM

when reinstalling the valve body onto the transmission case...

the kick down lever cam..  think of the small shaft thru the middle of the shift shaft or manual position shaft..    it looks like this from the outside in...

\\\\\\\\==================L

the end of the L needs to fit into a depression in the top of the valve body that limits movement to 1/10  of a turn..  one side against the stop.. and against the kick down plunger .. sorry i don't have pictures of this mating area ready to go... but when you look at the end of the inner shaft.. it should have a hard stop when you attempt a clockwise movement...

counter clockwise.. you should feel spring pressure...


so.. sorry.. you are at least going to need to drop the pan and the valve body again...

one more thing... on some years of the transmission. there is a TAB on the filter that holds a spring that pushes a CUP device up ward into the valve body..  if this is left out.. i don't know what will happen..

i spend the day under a 66/67 fairlane small block C4 2V carb.. it had several issues.

the throttle rod. was in the hole at the top of the linkage.. where it should have been in the hole closer to the shaft.. the pull ratio was way wrong...  

under the car.. the passing gear cable was incorrectly adjusted..  it limited the full range of throttle.. it actually stopped the throttle at about 1/4 throttle and man was it wedged hard on the kick down shaft..

if your kick down cam is holding the piston/plunger back.. it won't get third gear as you are holding it in passing gear...

do you have a C4 manual of some kind???? that shows trouble shooting...

i will look around for a kick down lever vs valve body kick down  image..  

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waynep712222
New User
Posts: 33
Joined: 05/13
Posted: 08/12/13 07:51 PM

by the way.... try driving the car with the transmission in what would be second gear...

perhaps you have an earlier unit.. that is a green dot... read this from the above linked articles.. before you tear it back down...


Big Dot, Small Dot
When the C4 was first introduced for '64, it was called the "Dual Range" automatic because it offered two driving ranges-normal 1-2-3 upshift with the selector at the large dot (Drive 1) or strictly second gear while at the small dot (Drive 2). Drive 2 doesn't have a detent like Drive 1 for the flexibility of slipping the shifter down into Drive 1, which does have a detent to prevent accidentally going into First gear unless the T-handle detent release button is depressed. The same can be said for reverse, which is locked out with a detent unless you press the button and move the shifter into Reverse or Park.
Ford did away with the Dual Range feature beginning in '67, which made the C4 easier to understand. Along with a new name for '67-Select-Shift-the later version switched to the more normal P-R-N-D-2-1 pattern.  

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mikew148
New User
Posts: 10
Joined: 07/13
Posted: 08/12/13 08:43 PM

I definitely got the kick down lever into the right area of the valve body and it does have the spring tension return. I made sure of that when the valve body went in. I lined it up perfectly when I slid the valve body into place and then engaged it a few times to be sure. Our 68 has the P-R-N-D-2-1 pattern and third gear used to work properly before the recent issues.
I'm going to take a look at the adjustment on the kick down cable tomorrow.

We have a shop manual with some decent detail and adjustment instructions.
Could the kick down adjustment keep it from reaching Drive? It has full throttle and has never run so strong.

When I installed the shift kit, I had to remove one of the plungers by pulling it out with a pair on needle nose pliers. It slid back in smoothly and I made sure it was operating freely before reinstalling the cover.

Thoughts?  Confused  

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waynep712222
New User
Posts: 33
Joined: 05/13
Posted: 08/13/13 06:56 AM

there HAS to be spring pressure return on that plunger...

if the plunger is staying depressed for any reason...

it will prevent third gear...

if enough check balls are installed... kickdown can go from 3 to 2 to 1...

i put them all in a 73 C4 for my friends father.. i also installed ported heads on his 302.. he was out racing ford mustangs with his 73 E300 ford van ..  it was strange being able to tromp the gas and have it down shift all the way to 1st gear... talk about winding the motor tight..   i would have taken them back out if he had let me.. but it worked for many years..

removing the valves from the valve body should be performed with magnetic tools..  or great care..

it sounds like removing the valve body again is needed.. at least for an inspection..

sorry.. this does happen.. even in transmission repair shops..

over tightening the valve body bolts.. is also a cause of failure..  

but so are damaged bores and valve pistons.. from plier damage.. i know you used care and did not damage.. i have had people walk in with tool marks on their valve body pistons before.. ask if i had any of these laying around..  

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mikew148
New User
Posts: 10
Joined: 07/13
Posted: 08/20/13 01:22 PM

Yea, that plunger was stuck in it's bore pretty good. A magnetic tool was not going to get it out. I used needle nose pliers to grab the center tip of the plunger. No contact was made with the side surfaces that move within the bore.

I guess the valve body needs to come out for another inspection. I should have looked closer at the inside of the bore and spring before reassembly. The shift kit didn't have a spring to replace the one in this bore. If there's a problem with it I should be able to find a replacement.....right?

Something caused that plunger to stick. I made sure to check for free movement and spring pressure before reinstalling. It was fine. I'm curious to see if it's stuck again.  

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