Technical FORD C6 TRANSMISSION HELP

I have never had a ford auto trans before so i know nothing!

I have a c6 behind a 390. Going from park to reverse shifts hard but works great. Going from neutral to drive doesnt engage really ot feels like its slipping or low fluid. If i go a little it kicks in and then works fine for a while i can slam the gas and its great and shifts fantastic. If I go back to neutral and then back to drive its back to slipping. I have the vaccum line to the manifold. I just replaced the vaccum modulator and turned the screw in clockwise to adjust to shift early. I checked the fluid and it seems At the right level. Its driving me nuts. Once i get it into drive its good to go i can come to a full stop then smash the gas and its very responsove no slipping and shifts great its just the initial neutral into drive. Any clue?

Thank you

 

I could be wrong but I think turning the modulator screw in will make it shift later
When you start out in drive if you pull the shifter to low will it take off like normal?

 

From what i read screwing counter clockwise or unscrewing makes it shift later. No low gears or anything engage from neutral into drive. There is a large "clunk" into reverse. neutral into drive you feel nothing. When you hit the gas it slowly inches forward and eventually it engages and im good to go drive anywhere and everywhere. Im trying to figure out what to do or what makes it shift from neutral into drive.

 

Have you pulled the pan and checked and/or replaced the filter? Have you considered taking to a trans shop for diagnosis?

Ray

 

Do you know the history of it? Had it long?

 

Sounds like the shifter linkage is not adjusted right. A c6 will burn up quick if it's off too much, I found out the expensive way

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You either have a sticky valve in the low gear circuit in the valve body or the forward clutch piston seal is getting old and hard which allows fluid on Dr pressure to blow by the seal. Once warmed up, the seal softens and flexes enough seal the piston to the clutch housing. If it only does it cold. I would blame the seal and figure an overhaul in the near future. If it does it every time or most often regardless trans temp, I would suspect the valve body.

 

Go to a parts store or Walmart and get a product call TransX. I've seen it solve many similar problems. It comes in pint containers for $6 at Walmart. A C6 has quite a bit of fluid so it might take 2 bottles. You should drain some fluid out to keep the level correct.

 

Ah, yes the magic seal sweller in a can. TransX can extend the life of a trans by 6 months to a year. K-D is the manufcturer. Just remember that if it works and then slips later, a second can won't help any more, rebuild time.

 

You have two bands . One of them is a reverse band. Very easy to adjust . But, your seals are probably hard ( do to age and heat ) and the only way to fix them is an O/H .

 

A C4 has 2 bands , low/reverse and intermediate. A C6 uses a low/reverse clutch which is not externally adjustable and an intermediate band which is. Power flow in a C6 is 1st: low reverse clutch forward clutch, 2nd: forward clutch, intermediate band, 3rd: forward clutch, direct clutch (also known as high/reverse), reverse: low/reverse clutch , direct clutch (hiegh /reverse). Notice that 3 of the 4 gear choices use the forward clutch. In forward gears it never gets a rest and relies on splash cooling. Thus the forward clutch piston seal gets hard and fails. Usually , the first indication is slow engagement when cold, commonly referred to as "morning sickness" at some point, the seal sweller liquids won't work and an overhaul is in order. An easy way to tell if it's the forward clutch is if it backs up normally in reverse. Since the trans is a 2 clutch or clutch and band operation and the low reverse clutch is used in both low and reverse, and reverse is good, than the other component in 1st is bad. That would be the forward clutch. And that would mean the overhaul
I just spoke of. Hope this helps.

 

K&W makes it. I was at a family reunion last weekend. 2 years ago it was at my house and one of my cousins was saying he was going to have to spend $2000 to rebuild his transmission because it was shifting roughly. I had some TranX so I sucked some fluid out and put the TransX in. I told him it might buy him some time. When I saw him Saturday I asked him about the car and he said it was shifting great by the time he got home and his daughter has been driving it for the last 2 years putting over 20,000 miles on it.

At work, we used it in hydraulic systems.

 

I got my specialty tools and additive makers mixed up. I have also used TransX successfully on several occasions. I haven't seen the mileage your cousin got but it does work. Funny thing, my youngest daughter called a couple of hours ago complaining of shift problems on her o/t Toyota. I told her to try TransX first too. Hopefully it will work and save some wear and tear on Dad's wallet. Since she is living on the east coast and I am on the west!