OK dude, didn't mean to start any flames over this, but oh my gosh...where do I start??

OK, I admit, telling you to call this guy and tell him he's wrong was a bit much. I made that comment based on the fact you and several people in various threads have stated this thing makes your tranny run that hot without any substantial evidence at all, only to finally test one and discover a much lower temp. My bad. But I'm perplexed at some of your uneducated comments. Without a gauge, your staments simply have no merrit at all because you simply don't know. And if you want to blindly follow what this guy tells you to do, so be it...hopefully he doens't tell you drive off a bridge. I like to know how stuff works. I like to make my own educated decisions. It's got absolutely nothing to do with trusting the guy that built a tranny or anything else...it's just the way I'm wired. I want to know how things work. you don't, no big deal.

I picked this thermostat based off educated observances on what my truck was doing. I don't have a stock cooler. I know my truck runs different since it's gotten cold. I know my tranny is not warming up because I have a gauge. I know this thermostat will help my tranny warm up, but not make it run any hotter overall during it's extremes. Educated analysis of all these items tells me its running that way because it's too cold because it doesn't run that way if I can get it to warm up...thus my need (or maybe it's fair to say want) for a thermostat.

I will concede that yes, it's possible thermostats can stick, and yes, the design of this one would prevent your fluid to cooling down below 135 or so. Cooling down to no colder than 135* isn't necessairily a bad thing though...that hurts nothing. But this thermostat (working properly) will not have an influence on your higher temps. If your tranny is running 180-190 degrees with this thermostat installed, it's still going to run that warm with it bypassed. That's an inarguable fact. Bypassing the thermostat may make it warm up slower, but it won't alter the ultimate temperature. You don't have a gauge...how do you know how warm it's running with the thing bypassed?

I also highly doubt the design of this thermostat and the chance of it sticking closed has contributed to burning up too many trannies. Even at full cold and the valve full closed, it still lets a substantial amount of fluid flow to the coolers. This thing failed closed is not going to completely block the fluid flow back to the tranny. An engine thermostat on the other hand doesn't work that way. When cold, it severely limits (and almost stops, not completely but almost) water flow to the radiator. So there it's easy to see how one of those stuck closed will be detrimental to water temp. Not a very good comparison.

And as for me personally, I have a gauge so I'll know if there's a problem.

And yes, we know the tranny needs a temp of around 95* supposedly for converter lock up...I mentioned that early on, maybe you missed it.

And while it's possible this thermostat has been changed over the years, I highly doubt there's a 50* variance between produced items...even at Ford standards. And Ford obviously put it in there for some reason.

 

That's what I was looking for...good enough! I know the direction of flow, I just wanted to make sure the lines weren't swapped from my tranny to yours or that I was mistaken from the last time I looked at one. Thanks bro!!

 

So let me get my facts straight here. You bought one unit new off the shelf and tested it. And with that one test on a product that may or may not have been redesigned you have decided that everyone else is wrong and you're right. Even the other guys who have a temp gauge and are getting the higher readings. Guys who have units made back in 04 are suddenly misinformed or wrong because of one test on a new product. Secondly I never accused this part of overheating my transmission. I'm not sure who said that. Third I don't blindly follow anyone or make uneducated statements. I ask for a transmission to be built to handle my 600+lb/ft of torque and racing slicks. When the guy builds it and says this how to take care of it and you won't have problems you do it. I love to know how things work to. I had to understand before I transformed this truck into what it is.

Now you mentioned wanting to know the hows and whys of these things. The earlist TSB's on them date back to 1982. The design was somewhat the same but it was based more on the path of least resistance and fluid dynamics. Ford was concerned with fluid viscosity in cold climates. Apparently very thick fluid was causing starvation / cavitation possibly causing transmission failures.

Thier "fix" was to install an "H" fitting in the cooler lines fairly close to the transmission. If the fluid was too thick, it would take the path of least resistance (thru the middle of the "H") and bypass the cooler altogether.

As the fluid warmed to operating temperature (at both ends) it would thin out and flow straight thru the "H" ... again taking the path of least resitance. This part was and always has been model dependant. If you have a cooler (tow package) it was installed. Pretty sure any vehicle sent to Canada had it but I can't prove that. At some point along the way a thermal check valve was added to improve the function of the product. For whats its worth I have read horror stories about these things sticking shut and burning up the tranny and this was also one of Darrin's concerns. Perhaps they have modified it a step further (temp for one and allowing some blow by if you will to prevent this single part from causing a failure, i don't know). With respect to your fluid not being warm enough, consider this. The fluid flows through the radiator to help keep it at a proper operating temp on the cold days. Basically if its not zero or less you should be ok.

I cannot find any good descriptive tsbs from Ford but this one from Dodge pretty well sums it up. I think you will find it interesting.
A/T - Cooler Bypass Kit/Restricted Fluid Flow
NO: 21-03-95 Rev. A
GROUP: Transmission
DATE: Jun. 16, 1995
SUBJECT:
RWD Automatic Transmission Cold Temperature Cooler Bypass Kit
THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETIN 21-03-95 DATED APR. 14, 1995 WHICH SHOULD BE REMOVED FROM YOUR FILES. 1993 MODEL YEARS HAVE BEEN DROPPED. ALL REVISIONS ARE MARKED WITH AN **ASTERISKS**.
MODELS:
**1994-1995** (AB) Ram Van/Wagon
**1994-1995** (AN) Dakota
**1994-1995** (ZJ) Grand Cherokee
1994-1995 (BR) Ram Truck
SYMPTOM/CONDITION:
At ambient temperatures of -15 degrees F or below, vehicles equipped with auxiliary transmission coolers may experience a lack of transmission fluid flow to the transmission. At these low temperatures, the automatic transmission fluid might freeze in the transmission cooler lines restricting fluid flow. This can cause damage to the transmission, and in periods of extended driving, transmission failure may result.
DIAGNOSIS:
The cold weather by-pass kit should be installed if any of the following conditions are met:
1. If the vehicle is used in areas of extended cold ambient temperatures (below -15 degrees F).
2. If the transmission has failed in cold ambient temperatures, install the bypass kit when repairing or replacing the transmission. Follow proper cooler flushing and transmission replacement procedures found in the Dodge Ram Service Manual.
Note IN HOT AMBIENT TEMPERATURES, THIS KIT WILL DECREASE THE COOLING CAPACITY OF THE TRANSMISSION COOLING SYSTEM. AS A RESULT, UNLESS THE ABOVE STATED CONDITIONS EXIST IT IS NOT RECOMMENDED THAT THIS KIT BE INSTALLED.**
POLICY: Reimbursable within the provisions of the warranty.
TIME ALLOWANCE:Kit, Transmission Cooler Bypass 1994-1995 (BR)
Install 1994-1995 (ZJ)
1994-1995 (AN)
1994-1995 (AB)
FAILURE CODE: P8 - New Part

 

Come on. Do it. Mr. Burch has a sense of humor. He'll get a good laugh out of it. I want to hear what he has to say.

 

to bypass it, you could just take it off, and drill out the lines through the block and put it back in

 

Yes that will work but u have to clog the center of it otherwise fluid would run to the cooler and through the block without ever going through the cooler.

 

Omg I can here him now. Lmao!

 

Not much different. Lower outlet on radiator returns fluid to transmission.

 

While you're at it, give Mike Troyer a call too. Make something up. Tell him he is completely off-base with his tuning, and that you know a better way od doing it.

 

Lmao. Now there's a thought. Good grief I can only imagine the ramifications.

 

Come on guys, give me a break...I admitted that was a bit much!

Fifty...thanks for the extra pic, but I meant I had replaced my stock cooler with a larger one, not I didnt have one at all.

 

Now that we are so many years down the road, has anyone solved the tranny cooling issue?