C6 Break In

[divemaster5734]

Have put under 50 miles on the truck since a c6 rebuild.
It's steadily performing better, getting a lot more power to the wheels now than 1st drive.
The truth is, this is a 34 year old idi box truck still half full of crap when it was used as extra storage during the years it was non-op, and I honestly have nowhere to go with it.
The result being about 4 or 5 trips in a 6-8 mile loop.
It's gone from waiting 30 seconds to engage after shifting from park to drive, and then slipping once or twice at a stop sign, to only taking about 5 or 10 seconds to engage when cold, with a possible minor slip at the stop.(If I can manage a rolling stop it wont slip, only if it disengages the drive clutches.)
Once I drive around the block it works perfectly.
Downshifts as speed drops, holds 1st to about 20, 2nd to about 30, then runs at 65 effortlessly, unless I'm giving a little extra throttle, then 2nd holds to about 40.
Going up a hill the kick down does it's job.
Getting back it will immediately and quietly shift to and change of direction or function, and the pawl sets as it should.
The fluid is so clear it's difficult to read the dipstick.
Looked around and couldn't find a break in mileage or recommended break in use anywhere.
Would really hate to destroy all the work through sheer stupidity.

 

[Cubey]

Sometimes you have to look at both sides of the dipstick, depending on which way it dipped in.

A properly rebuilt c6 with a proper level of ATF shouldn't be slipping or having a 30 second delay.

The 27ft RV pulling a small box trailer full of stuff didn't have any such problems being a freshly rebuilt transmission, crossing mountains of the NW and all.

You can adjust shift points in two places: and VRV on the side of the injection pump, and down on the transmission where the one vacuum hose attaches on the vacuum modular.

Usually all aftermarket vacuum modulars have a tiny adjustment screw inside the vacuum hose barb. Turn it clockwise for later up shifts, counterclockwise for earlier. It's a bit easier to adjust than the VRV.

 

[divemaster5734]

That's exactly my point.
Once fully warmed up it operates perfectly.
I put a diesel/tow stage 1 shift kit in, but didn't drill the extra hole in the valve body, which is an optional mod.
It's only starting out cold.
I used liberal amounts of Assemblee Goo, both green and blued, around 1/2 a tub total, as it's good for lube during initial startup, and will reduce friction plate loss until the oil circulates.
One of the threads I read somewhere said 500 miles, but it was referring to a more advanced R11.
New VRV and TC, replaced every bushing as well.
I think I'll just make time to put some mileage on it during light traffic and see how it goes after 100 miles.

 

[Cubey]

Sounds like low fluid, frankly. Oil expands as it gets hot, could explain why it doesn't work right when cold.

 

[divemaster5734]

I agree, but can't find an OEM E350 dipstick.
Mine is original, and has seen better days after decades as a rental vehicle.
I have a feeling I'm sending the dipstick in too far for an accurate measurement, but have nothing to reference for correction.

 

[Cubey]

I agree, but can't find an OEM E350 dipstick.
Mine is original, and has seen better days after decades as a rental vehicle.
I have a feeling I'm sending the dipstick in too far for an accurate measurement, but have nothing to reference for correction.

Get a dipstick and tube from a truck? it'll make it very hard to check, but it'll dip properly.

Here's a flexible one.

https://www.speedwaymotors.com/Ford-C6-Flexible-28-3-4-Inch-Transmission-Dipstick-Firewall-Mount,231395.html

Another for much less:

Pardon Our Interruption...

or a stubby one: https://www.jegs.com/i/JEGS/555/61613/10002/-1

 

[The_Josh_Bear]

Just to be certain:
You're checking the fluid with engine idling, yeah?
+1 to check both sides of dip stick.

And why is your fluid clear? Was the ATF not dyed?
Our work trucks are Allison 3000's and run long OCI's with a lot of hours, so eventually the ATF turns clear but that's months and years down the line. That's my only experience with clear ATF.

 

[Cubey]

And why is your fluid clear? Was the ATF not dyed?

Fresh ATF can be very hard to see on the dipstick because it's so clean and not darkened from use. Plus a 35 year old dipstick isn't silver and shiney anymore unless you scour it.

I find that fresh engine oil is hard to see too.

 

[The_Josh_Bear]

I agree that fresh stuff is harder than old stuff but it's still red.
Oh hey I just thought of something, you can always dab a paper towel on the stick and check level that way, even if you can't see it!

 

[divemaster5734]

Just to be certain:
You're checking the fluid with engine idling, yeah?
+1 to check both sides of dip stick.

And why is your fluid clear? Was the ATF not dyed?
Our work trucks are Allison 3000's and run long OCI's with a lot of hours, so eventually the ATF turns clear but that's months and years down the line. That's my only experience with clear ATF.

I agree that fresh stuff is harder than old stuff but it's still red.
Oh hey I just thought of something, you can always dab a paper towel on the stick and check level that way, even if you can't see it!

As @Cubey said, perhaps it's the dipstick.
Mercon V is obviously light red.
The question is where exactly is "bottom out" position, as the OEM one is severely worn, and missin any kind of stopper that would seal the end.
There's a cap, but that moves freely along a 1 1/2"-2" section, just before the loop- used to pull it out.
There's under 100 miles on it, but decided to change the atf early,( was already planning to change at 500) both to check for excessive debris, and also to hopefully use the new 5qts to calibrate the fluid level, assuming the TC is full with 7.
I'll measure the stick, but it's much longer than the F series, as the van ones extend to to front of the engine, to above the alternator.
I'm betting it's at least 3' long, probably a little longer.

 

[Cubey]

the dimple on the dipstick near the handle is where a little metal shield rests, so that should give you a pretty close idea of where it should stop.

easiest thing would be to buy one of those aftermarket ones I linked. you'll just have to pull back the doghouse to check the ATF, which admittedly would be awful to do often. But it's better than destroying the transmission.

 

[divemaster5734]

the dimple on the dipstick near the handle is where a little metal shield rests, so that should give you a pretty close idea of where it should stop.

easiest thing would be to buy one of those aftermarket ones I linked. you'll just have to pull back the doghouse to check the ATF, which admittedly would be awful to do often. But it's better than destroying the transmission.

Thinking about that I do have an extra F350 tube and dipstick. Would have to change the tube also, but then could possibly reach in from the front.
I'd rather recalibrate the OEM, and install some kind of barrier to hold that shield in place.
The pan drain and new fluid will confirm placement.
Thanks

 

[The_Josh_Bear]

Could you measure how far the truck one sticks past the end of tube and measure the tube length on the van and then do the math after that? I'm sure the tube on a van is about impossible to measure though...

 

[Cubey]

Unfortunately, I never measured the C6 dipstick on the RV. My 89 has E4OD, so that's probably no help.

I checked the MPC and grabbed these part number sections for you. They're all in reference to C6:

Tube:

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Dipstick:

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(For those who don't know, 6.9 is 420, 7.3 is 445)

 

[Cubey]

I'm sure the tube on a van is about impossible to measure though...

It wouldn't be difficult with a flexible tape measure, with the doghouse removed. You might need an assistant though, unless you tape down one end of it.

The round metal on the far right is the C6 dipstick tube on the RV. The turbo downpipe is a bit in the way in the picture.

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