Tranny cooler installation

[SummitUp]

Originally Posted by chris4851

I will be installing a tranny cooler soon. I had a couple questions before I placed the order. I live in Massachusetts, would you recommend the bypass? What exactly is the benifit of the bypass? Even if you live in a vey cold climate is there a downside not having the bypass?

I was looking into purchasing the Flex-a-lite 4120, how has this cooler been working out?

I can't speak for the the Flex-a-lite 4120 as I purchased the Tru-Cool Max cooler. I live at 9000ft. elevation in the Colorado Rockies (yeah, it gets real cold here on occasion!), so I ordered my cooler with the bypass option. The bypass is supposed to work in the same way the coolant thermostat in your engine works, i.e. it wont open to allow free flow of tranny fluid until the tranny has reached operating temperature.

However... I had nothing but problems with the bypass on my cooler. Tranny usually ran way too hot, so much so I thought the bypass unit was defective so I ordered a replacement. The replacement bypass unit wasn't any different and the tranny temps were still way too high even in cold weather so I re-plumbed my cooler without the bypass and never looked back.

Yes on really cold days it takes much longer for the tranny to "warm up" but in my case I never take my H2 on short trips so it doesn't really matter to me. What does matter to me is I wheel my "Deuce" hard on trails in Moab often in hot weather conditions so I need maximum flow of tranny fluid through the cooler and that isn't going to happen with the restriction the bypass unit places in the circuit.

Just my $.02

[chris4851]

I pulled the car in the garage this weekend to have a look at the bypass procedure before I purchased everything. I have a 2005 H2 and noticed that I already have a stock external tranny cooler. Is there any reason not to just bypass the radiator and still use the stock tranny cooler?

[Egan]

Originally Posted by SummitUp

Not possible. H2's never had factory installed external transmission coolers. If you do have an external tranny cooler than it was installed as an after market add on by the previous owner. Is it possible your thinking the power steering cooler is a tranny cooler?

It would be great if you would post a pic of this "stock external tranny cooler".

It's that thing in Step 1 above (post #2).

[chris4851]

Originally Posted by Egan

It's that thing in Step 1 above (post #2).

Correct. What is the cooler in Step 1 above, which is attached to the two vertical brackets? I believe the power steering cooler is to the right of this cooler. Also behind this cooler is another cooler then the radiator. What are they all for?

[Egan]

Originally Posted by chris4851

Correct. What is the cooler in Step 1 above, which is attached to the two vertical brackets? I believe the power steering cooler is to the right of this cooler. Also behind this cooler is another cooler then the radiator. What are they all for?

[SummitUp]

Well done Egan, and I stand corrected, there definitely was/is an OEM external tranny cooler:

[Egan]

Originally Posted by SummitUp

Well done Egan, and I stand corrected, there definitely was/is an OEM external tranny cooler:

It's a wonder any air gets to the radiator.

[iwillnc]

That would tell me that the factory cooler is more than likely sufficient as is.

[iwillnc]

As I quickly approach the need I do this myself, I've been thinking; obviously what's there is flawed and must be fixed, however I looked into why it went the way it did, while in sure many have long since figured it out, I just felt reason to state what I found
The factory unit allows the teams to heat up faster when cold, it's just as important for the transmission to be heated to a level as it is to cool it.
The factory unit also cools by use of liquid which inheritaly (sp) cools better than air

So by using just the stock external you lose the heating properties and a certain amount of cooling

Regardless of this, the system must be altered

[Hellz]

Originally Posted by iwillnc

As I quickly approach the need I do this myself, I've been thinking; obviously what's there is flawed and must be fixed, however I looked into why it went the way it did, while in sure many have long since figured it out, I just felt reason to state what I found
The factory unit allows the teams to heat up faster when cold, it's just as important for the transmission to be heated to a level as it is to cool it.
The factory unit also cools by use of liquid which inheritaly (sp) cools better than air

So by using just the stock external you lose the heating properties and a certain amount of cooling

Regardless of this, the system must be altered

im not sure that it is important for the tranny be heated to a certian level for operation. now if we are talking well below zero degrees, thats another issue.

i live in Minnesota, it is freezing or below freezing nearly half the year here. hell, we are expecting 8 inches of snow by tomorrow.. APRIL 11th !!!!
my tranny works and had always worked without issues when it is cold.

with my cooler installed.. i have seen the temp go up to about 120 degrees, but that is the max. 90% of the time though the needle doesnt move. it just sits right at the 100 degree mark.

by natural friction, the fluid/tranny will heat itself up to its rated viscosity. any additional heat besides that, that is the heat that needs to go.

[iwillnc]

How much fluid did you guys have to add to the system?

[iwillnc]

For goodness sakes, I'll be the beta tester then, I have the tru-cool in the backseat, but being worried about the A/C condensor flow, and the fact I feel 120 is waaay to low, I'm going to try using the factory cooler

As is my tranny never goes above 180, And I would be very happy at that temp as 175 is considered optimal tranny temp from what I see.

I don't want to regret spending $150 on a radiator, but I would be very happy if this worked.
But seriously the stock cooler is not THAT small.


Also if you never get it up to temperature it won't be able to get rid of the moisture in the transmission fluid, as well as it won't allow the TC to lock up as it's suppose to.

[iwillnc]

Update, I've done the loop to stock cooler avg temp is 178 so far has got up to 185.

Outdoor temperature is about 80 F

At the moment I can't say whether this is a success or failure, although its leaning toward a failure, I'll know for sure when the outdoor temps hit 95+
I'd like some wiggle room on the temp, I'm sure the stock would be fine if your max temp was 70, but I'm not sold on it as is.

If at any point the temp hits 200 then I will be putting on my aftermarket cooler.

Driving varies between in town to country roads

If my max temp when outdoor temp gets to 90+, never goes above 190 then ill be adding a deeper pan, I haven't been offroad yet but I'm sure it would get hot

Quite honestly I never paid much attention to the trans before other than periodically checking it wasn't above 200, so if these numbers are normal, I can't say.

[ryaleon]

Originally Posted by iwillnc

If at any point the temp hits 200 then I will be putting on my aftermarket cooler.

Be ready to change it. I did the loop with stock cooler and yeah temps will reach much higher than 200. Especially on the highway. I then installed a slightly larger than stock cooler. It was a flexolite. Don't remember the model. It kept temps generally in the 200-215 range. Still too warm for me. Put the trucool and now its fine. 150-155 degrees.

[Hellz]

Originally Posted by iwillnc

Update, I've done the loop to stock cooler avg temp is 178 so far has got up to 185.

Outdoor temperature is about 80 F

At the moment I can't say whether this is a success or failure, although its leaning toward a failure, I'll know for sure when the outdoor temps hit 95+
I'd like some wiggle room on the temp, I'm sure the stock would be fine if your max temp was 70, but I'm not sold on it as is.

If at any point the temp hits 200 then I will be putting on my aftermarket cooler.

Driving varies between in town to country roads

If my max temp when outdoor temp gets to 90+, never goes above 190 then ill be adding a deeper pan, I haven't been offroad yet but I'm sure it would get hot

Quite honestly I never paid much attention to the trans before other than periodically checking it wasn't above 200, so if these numbers are normal, I can't say.

so if you have a aftermarket cooler.. why **** around with the OEM one?
i spent $5k for a new tranny.... granted i could have gotten a cheaper one.. but still.. if you want to possibly fry it.. knock yourself out.