Cold transmission better than hot transmission 5r55w

[marked man]

After finding dark fluid in my newly acquired 4.6L XLT I drained the pan and added the Lucas transmission conditioner and two quarts of fresh Mercon V.
The trans now seems to perform pretty well when cold.
However, half way through my drive to work when things are hot, I get the shudder on the 2-3 and the flair on the 1-2 at high throttle.

Just not the same animal between hot and cold.

So any ideas?
Is it a closed loop/open loop issue that the PCM is affecting or is it just the temperature causing a physical change in performance due to reaching operating temps?

 

[esclamada]

Is this a dying transmission that you put Lucas in?
Why not put the recommended ATF all the way?

Make sure that it's full at operating temp when you refill it.


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[JCUZ]

Sounds like it's low on fluid to me - this is usually more noticeable when fluid is hot and thinner.....

 

[turborich]

If you dropped the pan it will hold much more than 2 quarts. I'm not certain but I think mine took around 5 quarts when I dropped my pan. You have to fill it from the drain plug while it's running. Search it or google it.

 

[marked man]

Let me be clear.
At hot, i pulled the check plug for the first time and i got a pint of fluid out before it became a light stream. May have been slightly overfilled.
Seeing the color i felt the fluid was a bit old so i removed the pan plug and removed just shy of 2 quarts.
Installed a fill nipple into the plug and used a plunger pump add first the Lucas.
I then added the first quart of mercon and started the vehicle which was still warm.
I then wait for temp to stabilize, and end up adding almost all of the second quart before getting a steady stream out the check hole.
I believe this is the proper fill method. Funny that the fluid added assumed up to more that the fluid removed. The trans right away sounded different laying in the splatter of fluid.

I am confident the fluid level is factory spec. I also feel the addition of the Lucas improved overall fluid quality.
Am i fighting really really bad fluid and one bottle isnt enough to fix, but marginally improve?

Or assuming the fluid is now fine what would be best logical step?

 

[esclamada]

i'll tell you why adding additive (such as Lucas) is not a good thing.

http://web.archive.org/web/20100926133335/http://www.bobistheoilguy.com/images/lucas/lucas.htm

How do you measure the temp of the transmission when refilling?

 

[turborich]

OK, so you never pulled the pan. I would start by removing the pan and cleaning it, installing a new filter and then refilling with Mercon V as you did before.

As far as the trans temp goes, You can feel the pan. If it's warm then you will be just fine. No need for a code scanner to read the temp. Just make sure it's running when you fill it up. Once it starts to run out then it's full.

If it's still giving you issues then it's probably time to visit a reputable trans shop.

 

[marked man]

After a bit of advise from local shop I am going to replace the solenoid block and as much fluid as I can.
It appears possible the torque converter has a drain plug which would be helpful.
I read something about a cooler bypass valve in the body that prevents fluid from going to the cooler at the radiator until it reaches operating temp so plan to get it warm then using my old 4R70W process, pump the trans dry through the cooler line. Drop the pan, remove all parts and drain TC of equipped. Reinstall and then begin the refill process.

The vehicle was babied all its life so hopefully that is all it needs.

BUT, should I adjust the OD band while in there? Its used at 2nd gear according to another read, and could be weak.

Any inputs?

 

[Exproblems]

How do you measure the temp of the transmission when refilling?

I was watching a car repair show and they were refilling a transmission with fluid similar to the way these Explorers need to be refilled. They had the car up on a lift letting it run for a while, then they used a laser pointer temp gauge pointed at the tranny pan to check the pan fluid temp prior to adding more fluid to top it off. Once the pan fluid got up to normal operating temp, they began to pump in more fluid.

 

[turborich]

I was watching a car repair show and they were refilling a transmission with fluid similar to the way these Explorers need to be refilled. They had the car up on a lift letting it run for a while, then they used a laser pointer temp gauge pointed at the tranny pan to check the pan fluid temp prior to adding more fluid to top it off. Once the pan fluid got up to normal operating temp, they began to pump in more fluid.

This is what I do as well. A handheld inferred temp gun can be found at Harbor freight tools for around $25-$40 bucks depending if it's on sale or not.

 

[marked man]

Thanks. I happen to have one hanging in the garage and forgot about it.
I will verify temps prior to final fill.

 

[marked man]

Hurray,
The tranny shop hit this one on the head.
The $225 solenoid block from Rock Auto and 7 quarts of Mercon V have seemingly fixed my issues.
I do believe the shop that worked on it before I bought it did something stupid.
First, the tranny pan had hammer marks on the inside. I believe they must have bent the pan and for fear, if not reality, found the filter was messed up and they replaced it.
They did not use Mercon V as it was black and not so good smelling.
Poor fluid and iffy solenoids seem to add up to poor performance when warm. Still ran pretty good the first time down the street in the morning but was worse as heated.
So, new solenoid block and fluid have given it new life.