460 Ford Forum banner

1 - 20 of 30 Posts

·
Registered
Joined
·
33 Posts
Discussion Starter #1
So I got a a c6 rebuilt and drove the car about 1,000 miles. Trans worked fine, but couldn't manually shift into second when under partial to full throttle. If I let off to no throttle it'll eventually go into second, but no real manual control. 2nd to 3rd manual is fine, and the tran will shift through all gears just fine when in D.

Anyways, I figured that might just be how the stock valvebody works, so I installed a B&M shift kit, but no dice. Trans shifts harder in all gears, but still o manual control from 1-2. Additionally, it wont downshift to 1st manually until the car is going like 5 mph.

So, when I installed the shift kit I didn't adjust the front band, but I think I did everything else right, as the trans works ok.

So why do I have no manual control?
 

·
Registered
Joined
·
96 Posts
All of the c6 and c4 tranys I have had, 1st was 1st, 2nd was 2nd. Just like manual. Always do 2nd gear burnouts without shifting. Only time won't shift to man low is when speed is too fast. Could be a governor valve problem, but you say it works fine when in drive? Someone on here will know where to look for the problem. Good luck!
Scott
 

·
Registered
Joined
·
385 Posts
shiftless "Bstrd"

If you have a pre 1967 valve body there is no "2nd" gear selection.

What year is yours?
 

·
Registered
Joined
·
25 Posts
FWIW

I won't claim to be a transmission expert, but I have rebuilt a couple C6's. I can't claim what happens on all C6's but I know how mine works. Originally, You could select gears manually but the speed of travel still had veto power, so to speak. When I did the rebuild, I installed the B&M Transpak (when you say shift kit, are you talking about the "shift improver kit" or "transpak" ??? -- transpak = shift improver kit + manual control). The manual control part of the equation is obviously what we are looking for here in your case.

Now I can put it in 1st, and stay in first, or 2nd, and stay in second, with no up or downshifts, at ANY speed. (Handy for a 4x4.... sucks to have your tranny shift just when you start to get momentum.) Of course, in drive, original auto functionality remains. (As someone else asked about the year, this supposedly applies to 1967-1991 C6 trannys)

Anyways... that's how it works with my two C6's ('76 & '78).... hope one of us is able to help.

- Sid

PS - even so it sounds like you might have another problem as well, because with or without a Transpak kit the 1-2 shift should pretty much happen when you put it in 2nd anyway unless you just started moving and are accelerating really hard.

I'm not trying to be long-winded here, but let me try to get this out in a semi-coherent mess.
All C6's should pretty much act like a manual when upshifting 1 to 2 to D.... they will accelerate into the gear the selector is in and then stop until you bump it to the next one. The time it doesnt act like a manual is when you go back down... speed has veto power. 2 is reachable, 1 is not, unless you literally slow to a crawl. I think thats why we are getting different opinions here.
Its just like Dragz79 (Scott) said - all of his shifted like manuals EXCEPT when the speed was too high. Thats not true manual.
Which brings us to 2 points:

1 - In MY opinion, which is probably worth about a cent and a half, you need a Transpak or similar to get TRUE manual functionality.

2 - Also in MY opinion, what you are describing shouldnt be happening whether you have a transpak or not. It should shift to 2 when you go to 2, unless your really mashing that gas.... sooooo you might have some other problem (need more info to know what that problem may be - band, governor, servo etc)

Ok I'm done. Sorry for the essay
 

·
Registered
Joined
·
33 Posts
Discussion Starter #9 (Edited)
Ok guys, thanks for the input, lemme clarify my problem as there seems to be some confusion.

The valve body/trans is D5, so '75

So, in Drive, the transmission will shift fine through all gears, shifts at about 3-3.5k rpm under full throttle.

From a stop I can select 1st and hold first until any speed, trans will not shift, even if I select 2nd, the trans will stay in 1st and not shift. However, If I move the shifter from first to D, the trans will shift, usually into 3rd.

From D I can downshift into 2nd and hold second at all speeds. I can take off in second and the trans wont shift unless I move the shifter into D. However, I can also not downshift to 1st unless moving very slowly.

So the trans is a stock rebuild with a B&M shift improver kit. I expect not being able to downshift to 1st at higher speeds, but I should still have manual control from 1-2.

What's my problem?
 

·
Registered
Joined
·
112 Posts
Try This

I've had the same problem with my C-6 in my truck, this is what I did and it corrected the problem. Adjust the intermediate band. There is an adjustment screw and locknut, same side of the tranny as the shifter, just above the shift mechanism on the same side of the tranny. Clean all the dirt from the screw and losen the locknut, Tighten said screw all the way up then back off 1 1/2 turns, tighten locknut down while holding screw in place. Don't be surprised if you have to turn the screw in as much as 3 turns then back it off 1 1/2, it happens.
I'm no transmission expert by no means but this has corrected my problem in the past and I usually check it every couple of races after losing a race because of it. The same thing happened to another guy I race with, told him about my findings and fixed his problem also.
 

·
Registered
Joined
·
25 Posts
... good info ...

Sounds like a problem with the band.
Drop the pan and look for crud before adjusting it.
I agree. Check that first, then let us know, we can go from there.

GOOD LUCK!

(you might drill the pan and put in a plug if you havent already while its down.... in case you have to keep cracking the pan later on - it really makes it easier)
 

·
Registered
Joined
·
3,730 Posts
OP said it operates fine in drive. if 2nd gear -- band adjustment was off .. i think it would show up on 1st to 2nd
 

·
Registered
Joined
·
877 Posts
I have to agree with 2slow, the trans is working fine it just wont shift from first to second correctly unless the shifter is in drive. It sounds like you need to adjust the intermediate band, that controlls the 1 to second shift. If you need help with knowing where that is just let us know and we can direct you or do a google search for it.
 

·
Premium Member
Joined
·
1,311 Posts
I have had the same problem as the OP.

Turned out to be the cable from my Hurst Promatic shifter needed adjustment.
 

·
Registered
Joined
·
25 Posts
well, at least we are all in agreement now :D

crap - typed that before I got to page 2 .....
 

·
Registered
Joined
·
33 Posts
Discussion Starter #18
It sounds like you need to adjust the intermediate band, that controlls the 1 to second shift.
That's What I was looking for! Also should I adjust the front band while I'm under there? I distinctly remember the shift kit instructions had a procudere on how to do it (it was like step number 3), and I also remember I didnt do it.

Found This on adjusting the intermediate band, and I have a shop manual which will probably point me in the right direction, but if anyone has a 'how-to' on adjusting bands I'm all ears.

---------------------------------------------------------------------------------------------------------------------

Intermediate band adjustments on the C3, C4, C5, and C6:

All models have their adjusting screws tightened to 120 in.-lbs. (10 ft.-lbs.), but the turns back are different.

C3
1980, and earlier models are turned back 1-1/2 turns.
1981, and later models are turned back 2 turns.

C4
1-3/4 turns back.

C5
4-1/4 turns back.

C6
1-1/2 turns back.

This information was obtained from the Haynes Ford Transmission Overhaul Techbook # 10355. Page 6-6 states that normal wear of bands requires a band adjustment every 15,000 miles, or in situations where there are symptoms of sluggish shifts, delayed shifts, slipping, and in extreme cases a loss of drive.
 

·
Registered
Joined
·
877 Posts
The intermediate band is that big band in the front of the transmission. Their is a big bolt that sticks out the side of the transmission with a nut around it. Loosen the nut and torque to 10 ft pounds then back off 1 1/2 turns and then torque the big nut back down while holding the big bolt still. Don't recall the exact torque spec on the big nut, maybe someone call tell him, if not I will get my transmission rebuild book out tomorow and let you know.
 

·
Registered
Joined
·
25 Posts
tiger is 100% accurate, that's all there is to it.

... and the torque spec for that lock nut is 35-45 ft-lbs.
 
1 - 20 of 30 Posts
Top