Ford C-6 Transmission

GA Hitek.

One would think that tranny fluid is tranny fluid. Not the case. Hell, you'd almost think it was intentional. I was thinking maybe not changing out the filter would cause that......nope, not that fast. I think your right on target. Hopefully it's not too late to correct.

I ran into that problem with a Dodge Caravan. I just put "ATF" in it and it ate the transmission. With modern Mopar transmissions you use "ATF+3" or ATF+4".

I would recommend that he drain the transmission ASAP and make sure he puts the right fluid in it. If he is lucky, he might have a transmission which still works.

Ah for the good old days where if you didn't have ATF you used 5w motor oil.

Bill

Nice call HiTek!

Ga from here!

I would agree with hi tek wrong oil

You might want to remove the filter and fluid and change both. Sounds like the filter is plugged and pump is taking longer to get things going.

h

The c-6 use to require type F ATF,maybe now the mercon types of fluid super seeds it. Check the fluid and fluid level. If you did not change the filter do it,or at least make sure the o ring in the filter is seated into the valve body properly,if is not the pump will cavitate.One of the reasons your fluid is dark is when you drain the pan it doesn't drain the tq converter,it holds i think 3 quarts. I have had c-4 and fmx trannys do the same as you described,after changing the filter they worked normal.Both had many miles on them.if it didn't act like this before the change it is something you did. again check the fluid, change filter and check the o ring. You should also drain the cooler. Darren

The type F is for 1966-1976 trannies.

From 1977-1996 use Mercon

HTRN

There are only 2 things that will turn your fluid dark. Excessive heat. and clutch dust. If you did not overheat the trans, your clutches are worn. Change your fluid again, and be sure to replace the filter. Pay close attention to the seal between filter, and lower valve body. Use some brake cleaner to clean as much of the inside as you can. Refill with proper fluid, and retest.

If the same conditions remain, you are going to need a transmission rebuild. If you want to buy some time. you can try adding a couple of pints of a viscosity booster, like STP oil treatment, of motor honey. Yes, I know it is the wrong product, and in the wrong application. But if increasing your engine speed helps, and it is no longer a restrictive filter, it is poor sealing between piston, and cylinder wall on forward clutch pack, or low clutch pack. Thicker viscosity may help.

And it will not cost any more to repair weather or not you try it.

Good luck. Another thing that might help, is transmission sealers. These swell the worn seals in the transmission.

Hi Bob, I haven't heard of motor honey since I used it once in an old 64 Ford Falcon that needed rings so bad it wouldn't pass inspection. It lasted about one week, but when I dropped the pan , the inside of the engine looked like someone hung curtains in there.

Will it do the same thing to an auto trans?

hank

Not to that extent, because the C6 has 2.5 times as much fluid to dilute with. Also ATF is thinner than the oil you should have been using in that crow.

I have a product I get from Texas refinery that has helped in a few transmissions over the years.

I had a Cobra Torino with a c-6. When I first got the car ( with high miles), the transmission would slip till it warmed up. Once the seals in the clutch packs would expand from the heat it would grab just fine. It sounds like you have worn and hard seals and that they need a little heat to expand. I rebuilt the trans myself and work fine after that.

Knowing what you do now, would you have tried the suggestions posted first before rebuilding?

I knew the transmission had a lot of miles on it. So, it was pretty much a no brainer that I needed to go into it. Plus the fact that it is a known symtom of worn out automatics. Actually the clutches looked good when I took it apart. It was just the clutch pack seals that had become brittle with age.

The C series transmissions had a habit of hardening the Clutch Piston and Servo seals due to age and or lack of service. This can cause a no-go situation until the fluid and the transmission warm up.

Sounds like a rebuild.