Cooler Installation Kit? NOW WITH POLL.

Best Transmission Cooler Setup?

  • Cooler in radiator (stock)

    Votes: 0 0.0%

  • Added cooler without bypass thermostat (OEM TSB setup); transmission > radiator > cooler > transm.

    Votes: 7 58.3%

  • Added cooler with bypass thermostat; transmission > radiator > cooler > transmission

    Votes: 0 0.0%

  • Cooler only, without bypass thermostat; transmission > cooler > transmission

    Votes: 5 41.7%

  • Cooler only, with bypass thermostat; transmission > cooler > transmission

    Votes: 0 0.0%
  • Total voters
    12
1997ThunderbirdLXV6

1997ThunderbirdLXV6

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I could swear someone posted a while back that he had an original OEM transmission cooler installation kit. You know, that kit from the attached TSB.

I'm curious what all is included. I was looking at a Mark VIII in the junkyard which apparently has one of the TSB coolers:

20250701_124722.jpg

For the exit from the radiator, it had this specific piece, which I picked up:

20250701_141335.jpg

Then it's all 3/8" inner diameter hose to/from the cooler:

20250701_131158.jpg

What gives me pause is the return into the existing cooler line. First of all, it was cut off; not something I like doing, with the risk of metal shavings getting into the system. Secondly, they connected the hose using this fitting; I could unscrew the piece which the hose wraps around, but the other piece is stuck to the metal tube. Not sure how that works; does it "bite" itself into the tube?

20250701_124740.jpg

I also find it weird that they made the cut so high up, only to force the hose into a 180° bend; they could have made the cut further down.

Generally speaking, I'd prefer a sort of plug & play solution, which avoids the cut altogether. Some fitting that just screws to the existing tube, plus the piece I pictured above which screws into the radiator.


I've been a bit resistant against the transmission cooler installation, but I guess I should give in to peer pressure. I do monitor transmission temperature on longer drives using my OBD2 app. At 60 mph, with ambient temperatures in the 90°F range, it usually settles around 180°F. At 70 mph, it settles closer to 195°F, a bit higher when there are hills.
 

Attachments

Did you buy that cooler? It looks decent and big enough for a stock setup. They are pretty simple install; compression fittings are fine. Even hose clamps are okay to use, it not a high-pressure location.

You got the radiator adapter which is good. IIRC they are kind of hard to find. I think I still have my aftermarket one in storage, from back when it had the automatic
 
Kenz said:
Did you buy that cooler?
Click to expand...

No. The only thing I bought was the radiator-to-hose adapter. I figured I should get a new cooler; who knows what this one looks like on the inside. Also, this cooler doesn't have any kind of bypass thermostat, which I think would be a disadvantage in the winter (?). The bracket is Mark VIII specific, so I didn't pick that up either.

I meant to buy that compression fitting, but based on @dDUBb 's explanation, I'm guessing they are single use.

Kenz said:
You got the radiator adapter which is good. IIRC they are kind of hard to find.
Click to expand...

Right. But on the other hand, one could just use another compression fitting on the original cut-off tube. That's why I'm curious what all was part of the original Ford installation kit.
 
1997ThunderbirdLXV6 said:
Also, this cooler doesn't have any kind of bypass thermostat, which I think would be a disadvantage in the winter (?). The bracket is Mark VIII specific, so I didn't pick that up either.
Click to expand...

General consensus is that the radiator isn't really needed to warm up the fluid. Maybe in Siberia it would help
 
1997ThunderbirdLXV6 said:
I meant to buy that compression fitting, but based on @dDUBb 's explanation, I'm guessing they are single use.
Click to expand...

The ferrule is one time use .. but the other two parts ( nut and adapter ) can be re-used with a new ferrule. Its about $10 worth of hardware brand new. Replacement ferrules are cheap but you'd need to cut the line below the old Ferrule to remove the nut - just to save a couple dollars and re-use 20 year old fittings.
 
Kenz said:
General consensus is that the radiator isn't really needed to warm up the fluid. Maybe in Siberia it would help
Click to expand...
Agreed, I have a large cooler and the radiator bypassed, no issues this past winter which was much colder than usual around here.
 
Regarding bypassing the cooler in the rad, a lot of newer cars no longer even have the cooler as part of the rad. A lot of cars now combine the AC condenser with the trans cooler along the bottom of it. So there is no need to keep the radiator mounted cooler. In my mind, that is just a liability since if it fails it will cross-contaminate the fluids, which will quickly kill a perfectly good transmission.
 
Ok, Mike, I hear you, but up to now I thought that the cooler in the radiator was specifically intended to heat up the transmission fluid. Judging from the times I monitored temperature using the app, it takes a while to get up to temperature, which could pose a transmission durability issue in itself (?).

MadMikeyL said:
a lot of newer cars no longer even have the cooler as part of the rad. A lot of cars now combine the AC condenser with the trans cooler along the bottom of it.
Click to expand...

I think that's how late model Panthers are. Anybody know for certain?

In that case however, would that transmission cooler have a bypass thermostat so that the fluid only goes through the cooler once it's warmed up?
 
I'm running my fluid thru the new radiator, and then thru a universal cooler. My theory is the radiator takes a few degrees out of the fluid, and then the cooler pulls even more. There is enough room between the rad and the condenser to mount a decent size universal cooler. That's what I would recommend. I wouldn't search for the Ford unit.
 
There is no reason to heat up the transmission fluid. The hotter the fluid, the faster it degrades. The hotter the fluid, the faster seals inside the trans dry out and fail. The hotter the fluid, the harder the pump has to work to maintain line pressure, and a drop in line pressure can cause slipping and wear. You don’t want your transmission fluid hot. You want it cold, as cold as possible, short of extreme sub-zero temperatures that could prevent it from flowing. If you could keep your transmission fluid at ambient temperatures all the time, the transmission would last forever and the fluid would probably last 150k miles. Heat kills transmissions. Heat is the enemy. Unless you’re in Siberia or somewhere else that sees -40 degree temperatures, there is absolutely no reason ever to purposely introduce heat into the transmission fluid.
 
Agreed with what @MadMikeyL said... Also, perhaps Ford kept the radiator cooler as an antiquated design carry over from back when synthetic base oils were not around. With old style conventional ATF fluid it could serve a purpose, but modern synthetic fluids have good flow even at low temperatures.
It could also have just been a cost savings to put two systems into one unit :zshrug:
 
Kidd-7 said:
Agreed, I have a large cooler and the radiator bypassed, no issues this past winter which was much colder than usual around here.
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Back when I lived in upstate NY I many a times started my Tbird up on -20° winters and the transmission had no problems going before warming up. Sometimes it was so cold the shifter didn't want to get out of park. I think that was just the lines to the brake interlock getting stiff.
 
I don’t miss those cold mornings. 🥶
 
Is the poll for MN12s or Panthers? :unsure:I don't think our cars have any kind of transmission thermostat, unless the pool is for coolant thermostat?
 
Kenz said:
Is the poll for MN12s or Panthers?
Click to expand...

For MN12 primarily, though it applies the same to Panthers before they eliminated the in-radiator cooler.

Kenz said:
I don't think our cars have any kind of transmission thermostat, unless the pool is for coolant thermostat?
Click to expand...

Correct.
The poll question is: if you purchase an additional cooler, do you select one with or without a bypass thermostat?

A third option would be the type below, where the manufacturer claims a sort of "passive" thermostat:

 
Pretty interesting result as of now!

Agreement that the cooler doesn't need an integrated thermostat (just one more thing that can fail I guess). But no agreement regarding the in/exclusion of the stock radiator cooler.

Screenshot_20250702_202009_Samsung Internet.jpg
 
I would vote for external cooler and the radiator cooler, but only if the radiator was new. With an old radiator best to get it out of the system
 
If the fluid gets too cold it will unlock the TC, and go into open loop. But that's coolant temp.
 
1997ThunderbirdLXV6 said:
Oh, it's old. Presumably the factory radiator.
Click to expand...

Same here... Thought about replacing it just because of the age. Surprisingly though most of the plastics in the engine bay are not brittle and have held up well over time. I plan to run it until it fails, if I have a long trip or end up driving it more it's getting a new radiator.
 
At this age I suggest replacing the whole cooling system when you go.
In a matter of months and I forget the exact sequence, but each one was a failure that put the Smurf down for a few days each.
Heater hose split
Upper radiator nipple broke off
Heater hose nipple on the intake broke off
I also replaced water pump, I think that was preemptive though.
After these repairs she ran much cooler though.
 
I don't really have a strong preference for with or without the factory rad so I voted with the factory rad. My son's 2006 Durango just has an external cooler from the factory. I've never seen a bypass thermostat in a trans cooler circuit. I get the concept. I just don't know what it really does for you in the real world other than add another failure point.
 
When you build a 4r100 for the SD's you usually get rid of the t stat.
 
Could you all post some pictures of your coolers installed? Especially what type of bracket you used, what it's attached to, and how you routed the hoses?
 
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