C4 woes, possibly fluid?

[iwlbcnu]

Sorry, long story no matter how I try.....
Had a C4 rebuilt, new convertor, new radiator, was running Mercon V and the intermediate band broke, maybe 2000 miles, but at least 5 years. Being lazy, I had a second rebuilt at another shop, new convertor, and blew out lines. Swapped it in using Redline D4 ATF and was having shifting issues right away. Builder was to far away so I have been trouble shooting myself. He had me swap valve bodies from first trans. And that fixed the issue........... so, me wanting to end up with two good transmissions, tore into the valve body and found the 1-2 and 2-3 valves stuck. Cleaned them, got them working and reswapped.
All was fine for roughly 100 miles and then shift issues again. So I reswapped. All was fine for roughtly 100 miles and then it wouldn't shift to third unless really high rpm, found out passing gear was stuck in. So I spent alot of time and really went through the second valve body and made sure it was clean and working freely. Did another swap, and the first valve body was working good except for a 2-3 flare up. Well that lasted roughly 100 miles and now 1-2 valve is stuck again.
So.....each time I have just drained the fluid, strained it and reused since relatively new, but am thinking it has to be the cause. The second valve body never had an issue until in this fluid. Each time it takes very little to unstick the valves, seem to be working smoothly, but then stick after use.
The builder says I can switch back to plain old Mercon V so that is my next step, just looking for input. Really hate throwing $200 worth of Redline away.

 

[Rightpace]

I know for a fact that redline D4 is not a replacement for mercon v. I wouldn't use anything but type F in a c4 transmission. If you look at the properties of type F you will see that no other fluid is compatible. Drain the system and use type F, if there is no major damage already done you will be good. C4 Valve bodies are dependent on the properties of the type F fluid the transmission was designed for.

 

[iwlbcnu]

Everything I have read and asked have said the clutch materials control what fluid is needed, def had no issues running Mercon in the last. What is making the mechanical part controlling this?
Around here Type F is hard to find except for the Wal-Mart or Fram brand. What are you finding to recommend?

 

[Rightpace]

Viscosity of fluid and friction modifiers is the reason for different fluids. Your cast valve body and steel valves are heat transferring, when the fluid isn't doing the designed job, these mechanical/ hydraulic parts fail to operate correctly. Air introduction or foaming are usually the first problem.

 

[Broncobowsher]

What is sticking the valve?
Is it a varnish type of deposit? The valve is glued into place.
Is it a debris induced stuck valve? A rock wedged in the valve?

Varnish is a fluid based failure, which may be caused by a thermal issue (bad cooling)
Debris is either it wasn't cleaned to start with or something is falling apart inside.

 

[iwlbcnu]

That I have no idea, to unstick I just use a stick magnet and push and pull and after 2-3 times it moves again. I pulled them out and used an engine brush to clean out. I really see nothing to be the problem. Def no trash, so has to fluid related. I highly doubt I have a cooling issue on the trans. Previous trans never had a shifting problem. the band just came unadjusted and I missed it before doing the swap.
Too many projects, not enough time to properly diagnose before doing the swap.

 

[73azbronco]

all it takes is a spec of dust to jam a valve body. Fluid type is critical.

 

[iwlbcnu]

Okay, thanks guys, just ordered 24 Amalie Type F.

 

[broncnaz]

What I've always heard is dont switch oil types in automatics. Supposedly when you rebuild you can run a different oil than stock but once its been run it needs to stick with that oil. So what your builder recommends should be what you use. But as was said friction material may be a factor. old type F oil was standard due to no friction modifiers in it. the frictions they used required it. Supposedly the new friction materials can use mercon III/mercon V. Maybe the full synthetic redline is not backwards compatible or is allowing to much slippage and building heat hence the sticky valves.

 

[56f100bbw]

My 77 bronco c-4 was rebuilt 27k ago and the rebuilder said I could use Mercon lll and no problem so far , but my 77 c4 has 3500 miles on it and slips a little still sorting issues same builder and mercon lll from the start when rebuilt

 

[Pa PITT]

OK I'm an old parts man from back in the days when C4'S WERE THE TRANS in our old Ford ... My Town had an old man that rebuilt trans of all kinds & He traded with me .. I sold him the ATP Trans kits & lot's of DEXIII FLUID .
.... hE SWAPPED THEM ALL OVER FROM TYPE F..
.. bUT HE always told me you could never get the C4 VALVE BODYS TOO CLEAN.
a LOT OF THE ONES HE DID. They had to remove & clean the Valve Bodys again & again.
... HE WOULD Place them on old white sheets on his bench. No fan blowing on him in the summer . He said any particle of dust would make it not work .
..... SO FINE A WAY to clean it I'll say with Berryman's spray cleaner. & Wear white gloves & soak every thing in more new ATF..
...... KEEP IT EXTRA CLEAN.

 

[Rustytruck]

Are you torquing the valve body bolts they are really sensitive to pressure and can tweak the casting if over torqued or uneven pressure. I don't remember if there is a torquing sequence pattern it been a long time digging into the service manual.

 

[ol gray mare]

I agree with PaPitt. I just went through the same scenario. The last time I removed the valve body, I used brake kleen and a a brass wire brush from my gun cleaning kit. The valve body is not clean enough until the valves can slide in the body by tipping them so gravity will do it. As a matter of fact, that's what the guy in the Bad Shoe video said. I didn't take him seriously and paid the price in frustration and extra work. Jim

 

[iwlbcnu]

Welp, that was a bust! Drained trans, and convertor, used 4 quarts to flush system for a few minutes, drained and refilled. Did good for about 8 miles, now shutters in first, and second is slipping.
I think I'm done!

 

[Rightpace]

Curious to know if the old fluid had metal particles (ultra fine). 2. If the second gear band was adjusted to snug and let off correctly. 3. If transmission fluid had foamed at operating temp on the dipstick after driving.

 

[iwlbcnu]

So, I have drained the fluid at least 5 times changing valve bodies. I have not seen any material in the fluid, BUT each time I pull the pan, I have to clean out a black film coating it. I have not noticed the fluid foaming, but didn't get to check last night, got interrupted upon getting home.

 

[Rustytruck]

when the trans work was initially done did you replace the converter? and flush the tranny cooler?

 

[iwlbcnu]

Welp. new fluid ended that! Made it 14 miles and lost all forward gears.