By the way, thanks for your prompt reply Mark. I appreciate it. I'm sure the other members on this forum are happy to have an experienced mechanic on hand for
professional advice.

 

\
uhm, see above !!!
Hello, is this thing on ?

 

The bypass doesn't help warm up at all. It only bypasses if the cooler is plugged, or the bypass fails.

To check for cooler circuit restriction warm up the truck by driving at least 10 miles.

Have two buckets, each at least a gallon. Remove the cooler line where it attaches to the rear of the trans. Put the line in the first bucket. Have a friend start the engine, leaving it at idle and in park. When the flow from the line is steady (should only take a few seconds) put the line in the second bucket FOR EXACTLY 15 SECONDS then back into the first bucket and shut the engine off.

If fluid sprayed out of the trans where you removed the line either the cooler circuit is plugged or the bypass has failed. If there is at least one quart of fluid in the second bucket you have enough flow.

To check for air blockage you need to look at the cooler and see if it is packed with debris.

 

Thanks again Mark. I'm running up a pretty big bill for your knowledge. I think I should do this and see if I am right. #1. I connected the sensor for the tranny gage
in what I believed to be the correct 'test port'. That is the plug right behind the brace
that holds the cable for the shift selector. The 1/8 NTP fit exactly and I was sure this
'had' to be the place. Unless there is something I missed this has to be the place, correct? Took out the front grill, washed out all the a/c condenser fins, tranny cooler, p/s cooler and radiator. Didn't seem to be too dirty or clogged on any of them. So, with the grill out I went to town and back (total 20 miles) and by the time I got back the gage was about 240 with a 65 degree day. I know the tranny cooler is
hidden behind the a/c condenser with only about 2-3 inches hanging below it, but I figured Ford should have considered that when they installed it that way. Anyway, since the gage showed that it was so hot, I figured I'd crawl underneath and see how
hot the lines were..........they were almost cool. The pan was pretty warm, but not as hot as I would have expected. I could hold my hand on it and it was pretty warm, but I didn't have to remove my hand because of excessive heat. It just didn't seem
like it should be that cool with a gage registering 240. So, with your advice about checking flow to determine if cooler is blocked or bypass has failed I'm trying to think what I should do next. First I'm thinking of removing the sender and putting it into a pot of boiling water and see how the gage registers. Somehow I think the gage is probably correct. The cooler was not filled with trash/mud, gunk, it was pretty clear actually. So that leaves the bypass. Something tells me to forget all the rest and just replace the bypass line and hope for the best without wasting time on the other 2 options.

The cooler line that attaches to the rear of the tranny as you mentioned for flow, I am assuming that is the return line?

I plan on installing a Tru-Cool cooler when it arrives next week, that's the reason I went ahead and removed the grill. Looking down on the cooler standing in front of the truck there are cooler lines on my left and then one line goes along the top of the
cooler (approx 2 feet) to the right hand side. How do I identify the return line and how do I connect the two 'coolers' together. I may be in over my head here since I'm not real sure how to connect the two together.

 

I think he meant that the INSIDE of the cooler is clogged, not the outside.
again, the only way to test this is to follow the procedure above.

 

rhouse, you are putting lots of effort but you are seriously attacking this thing the wrong way. See below:

Now stop here and think a minute. We know that the transmission fluid should NEVER be run continuously above 230° except for a short period of time. So logic dictates that when folks like Mark(yup, transmission engineer not mechanic) designed these things the intent was to be able to tow things in warmer weather than 65°. So if the stock cooler is truly inadequate to keep your transmission cool in mild temperatures, I think it's fair to say that it is NOT functioning correctly. Causes could be:

(a) lack of airflow through the fins; this would be caused by an obstruction.
(b) obstruction in the cooler which isn't permitting flow

Since you can't find anything obstructing the fins I think it's fair to assume that your cooler is blocked internally, and therefore you are having minimal, if any, flow through the cooler.

Why would this be? If your transmission is getting HOT and the lines are cool, the only possible cause would be that your hot transmission fluid is not flowing to the cooler. Otherwise one line would be hot, and the other would be a little bit cooler.

How fast the pan will burn you has to do with the speed at which heat is conducted between that pan and your hand and the exterior temperature of the pan. You simply can't get an accurate picture of what the internal temp is by feeling the outside of the pan!

What makes you think that? You don't think it's likely that the cooler can be blocked? Believe me it's more common than the bypass failing!


Stop. Hold. Do not pass go, do not collect $200.

Your cooling problem IS NOT lack of cooling capacity from your stock cooler. The problem is that something, most likely a blockage, is preventing your stock cooler from working correctly. Adding another cooler inline will make the problem WORSE because your restriction will increase.

Until proper flow is established you really need to be in diagnostic mode rather than modification mode. I apologize in advance if I come off a bit harsh here, I work hard for my living and it would bother me to no end if I spent a bunch of money and still blew up the transmission, which I feel you're getting ready to do. Please take the time, figure this out, and do it right rather than just throwing parts at it.

 

Thanks Tom. I appreciate every idea out there. I like your approach. Here's my problem. Could this new gage be wrong? Somehow I'm thinking if the stock cooler is
plugged internally, then the tranny has something seriously wrong with it from what?
Shavings from metal inside, clutch debris, what? How does the cooler get plugged
inside without something bad inside which I don't even want to think about. As far as I can tell the tranny is working fine except for that heat gage. I wanted to remove the gage this morning and check it in a pan of boiling water. Probably more wasted time. OK, so what about this Tom.......if I disconnect the stock cooler, take it out, how can I check the flow through it? Pour some tranny oil in it and use an air
compressor and blow it out? I'm sure you can tell I'm not a very good mechanic, but I try. I hate those 85 to 100 dollar an hour labor bills when I can use my own time.
Well, it's Sunday morning and I want some coffee.

Appreciate your comments Tom. And I know what you mean about throwing money and parts at it. The shop mechs do that a lot these days. But, in my own defense I guess, I was figuring if the bypass valve only cost 50 bucks I could do that and still come out ahead of a shop charging me 80-100 dollars just to check it.

Not to beat a dead horse, but let's say I uninstall the stock cooler and it appears plugged. What would have caused that? Don't tell me bad news. LOL. Not being a mechanic I'm back to thinking 'stuff' from the tranny and that's a whole nother problem. So, you think I should uninstall and blow compressed air thru it and see how much pressure comes out the other end? Thanks again. Bob. That's the r as in Robert in my email address rhouse1938@comcast.net.

 

No, I meant both inside AND outside. I see where the bottom three inches are clear, but I don't know what that means for the rest of the cooler. Is that space clogged with old leaves?

Yes, that's the right place.
That tells me that your problem is most likely the gauge. There is NO WAY the trans is at 240°F and you can hold your hand on the pan. NO WAY. The transmission is not hot, the gauge is wrong.

Good plan.

I don't think it is correct.

Yes it is.

You can trace the line from the rear of the trans forward and see which one is the return.

I don't understand why you need to do this, what difference does it make? You are going to replace the stock cooler with the Tru-Cool, right? You would NEVER think of adding it in series with the stock one, would you? That would just cause more restriction and almost guarantee that a normally operating bypass would open most of the time preventing the coolers from getting any hot ATF.

And if you were foolish enough to add a second cooler what difference does it make if it is before or after the second cooler?

 

It's very possible, but I think less likely than a flow problem through your cooler. If it's not a big deal to remove it and rig up in a pot of water it may be worth your while, but another easy technique would be to read the data from the factory transmission fluid sensor and see if it matches up. This requires a good OBD-II reader or something like a ScanGauge - Trip Computer + Digitial Gauges + ScanTools, but it would take only a couple minutes if you have the capability.

First of all, the vast majority of us aren't very good mechanics, myself included. But knowing where and how to find the information and logically go through an issue means that you really don't have to.

For testing flow you don't even have to remove anything, just follow the instructions Mark mentioned above:

This will take, no joke, less than five minutes after warmup if you have a helper to start the truck while you count seconds and pump into a bucket. No removal is necessary, and this will tell you with certainty whether or not flow is your problem. If it isn't don't even waste your money with the bypass!


Well...maybe! I don't have enough experience to say whether or not transmission damage is the cause of a blockage. I do know that as your transmission goes through its lifespan there is wear that occurs within the clutch packs and other internal parts, and this stuff will end up being circulated around your transmission and cooler if it's not blocked by the screen. I would think that it's possible for a cooler blockage without serious transmission damage, but I'm not certain of this.

I can say that damage most certainly will be done if this cooling issue isn't taken care of though. Instead of worrying about condemning what is currently a fine running transmission, focus on the problem at hand. You may get this sorted out and never have another issue, or it could die next week. It's certainly not worth a preemptive teardown based on a clogged cooler though!

 

Good morning Mark. Thanks again. You're messing with my mind now because the TruCool people (I thought) were talking about 'stacking' these coolers to increase the cooling effect. Reading reviews on the internet I'm sure others were talking about the same thing..........the trucool only has around 12 layers or about the same as the stock cooler, but if you put them in series you have almost what the other people were talking about with the 6.0 cooler. So are you saying with the trucool install I can't use both? Wow. Now that I'm reading more and more, I'm thinking that the trucool people were just saying their cooler is rated at 40,000 GVW, versus the stock cooler at 28,000 so you're almost double. That was not what I had been led to believe. I thought they were saying by connecting the two together you would have the tremendously increased cooling power. 20/20 hindsight. Then I guess the plan would be to uninstall the current cooler and just toss it and then when I install the trucool put it out in front of the a/c condenser for more air and maybe I'd be good to go.................As I said to Tom tho...........what would have caused the stock cooler to plug? I know you and others are getting tired of my questions, comments, etc. But, I'm tired of it too. Been working on this problem way too long.

But in any case, the bottom line on the cooler is: When I install the trucool, I abandon the stock cooler, right? Interesting how I could get so confused reading all those threads and was thinking they had connected the two in series.

Got to go. Thanks again Mark. Bob. r is the Robert in rhouse1938@comcast.net.
run the fluid thru both coolers?

 

I would junk the stock cooler when installing another cooler. I'm sure many people have installed the second cooler in series. I would never do that, and I think they are not getting what they think they are getting by stacking the coolers.

A transmission generates a fair amount of debris in normal operation. Clutches wear, gears wear, etc. Sometimes a larger piece (still fairly small, but larger than a dust particle) can stick in a cooler. Now the small pieces have a place to get caught and they just keep piling on.

 

OK, I got the plan for the trucool. But in trying to test the curent autometer gage that I installed I have tried this to no avail.

Took the sender out connected it to a wire to the sender post on the gage, put the sender in a pan of boiling water and no movement. Took it out to the truck and connected the gage to the ignition with power on, no movement, connected a ground wire to the gage, no movement. I am getting so sick of this!!!!!!!!!!!!!

Someone willing to post for me again and not getting fed up with my inability to properly diagnose this thing please email me at rhouse1938@comcast.net or post here. Seems I'm spending my life here.

I assumed (yeah I know that *** thing) that the sender would respond to hot water as easily as to the hot oil...........am I wrong here, and also is there another way to
test this gage or sender...........something is wrong somewhere. Thanks.

 

Now that's frustrating. Unfortunately I don't know exactly which gauge you have, and even if I did I can't find the installation instructions for much of anything on Autometer's website.

Your assumption was correct, the sender doesn't give a hoot what it's immersed in, because it's most likely reporting the temperature of itself. So when the sender is immersed in hot transmission fluid, the sender will closely match the temperature of the liquid, and that's what makes the thermistor have the appropriate resistance for the temperature.

If the wiring was exactly correct, complete with 12v power and ground at all points it should work. You're going to likely need to bring in a 12v battery to the kitchen and hook up the sensor to the gauge and apply power and ground from that battery to get this to work.

 

I'm just perflexed as to why I can't get a reading in hot water with the sender and the autometer gage connected just as if it were installed in the truck.

Sender in hot water, connected to the S plug on the gage, Ignition power connected to the I plug on the gage and then try a ground connected to the Grnd plug.............

No movement from anything except when ignition is turned on the gage which sets below the 100 mark will wiggle a small amount as you switch the ignition on and off.

Otherwise nothing...............I just don't get it. I feel like I must be stupid or something !!!!

 

You're not stupid at all, you're troubleshooting this in a logical manner. Don't get discouraged!

Simple explanation is that the sensor may ground through contact to the transmission housing. So the positive may be a wire that goes to the gauge, and negative depends on electrical conductivity between the sensor and the transmission.

Throwing out a shot in the dark here, but that would make logical sense. Try running a ground wire and wrapping it around the sensor while it's in the pot of boiling water and see what happens!