Write-Up: Transmission Cooler Install

potential points of failure?

Albertj

I assume they are referring to additional hoses and fittings,etc.as potential failure points.

I put one in my Chrysler LHS, took about 30 minutes.

Did GM make one for the Riv with hard lines instead of the aftermarket universal with hoses?
If so, them maybe a pick n pull or Morads for a good used one would eliminate or greatly reduce the additional points of failure.

Rick I had a 'factory' external cooler from a regal, but it ended up not being easy to install. I did finally get it hooked up and it leaked, so I have an aftermarket job in there.

I installed a transmission cooler because it's long proven over time that it helps transmission life, and I am known to drive my car pretty hard from time to time, so I think it's worthwhile. Yes, it adds a few additional points of failure, but they can be reduced by a careful installation, careful routing of the hoses and proper fittings and adapters to keep the hoses together.

Do not use the little mounting things that push through the radiator or condensor. They can eventually cut through a tube and give you more than you bargained for. There are plenty of other things to mount it to in front of the radiator. I'll try to take pics of what I strapped mine to.

I have had a tranny cooler installed on my '91 S10 that I bought new off the lot for several years now with the plastic push through fastener's with no problems what so ever. I think I installed the cooler at about 75K along with a B@M shift kit and now the truck has 290K and the tranny shifts like the day it was new. I think the key is to make sure the fastener's are tight to the radiator so they can't move around.

I've had many many tranny coolers installed, and I only had one problem with the push-through fasteners, but it was enough to turn me off to them. There are always other ways you can mount it.

Eldo was doing an aftermarket cooler install very recently.
Haven't heard any feedback from him on this topic.
I wonder how his install went.?????

albertj wrote:

potential points of failure?

From INTENSE Racing:

"Should I run a tranny cooler?

Only if you're planning to pull a trailer through the mountains. Otherwise, we recommend against it on vehicles with the 3800 FWD/4T65E drivetrain.

We have dissected more of these trannies than anyone else in the performance aftermarket, and we have yet to see a single heat-related failure. Hard parts break in these trannies, and these failures will not be prevented by a tranny cooler.

Tranny coolers add unnecessary weight and opportunities for fittings to leak. A leaking fitting can let your tranny run dry in minutes and ruin it far faster than a little heat ever could.

Our trannies are cooled by the same radiator used to cool the engine. So running a colder engine thermostat will make both your engine and your tranny run cooler."

From ZZ Performance:

"The idea of a tranny cooler is a good one. Keep the transmission running cooler and it will last longer. Fluid stays cleaner and parts last longer. Those are theories. The problem is the Grand Prix doesn't have a problem with transmission temperatures. A tranny cooler might be a great idea on some cars but the Grand Prix is not one of them. Little known to most is that the GP PCM monitors transmission temps and if the tranny temps get too high the PCM will set a check engine light and possibly take precautions to limit abuse.

We have done dozens of transmissions here at ZZP and we know from opening them up that a tranny cooler is not helping anything. We've seen tranny's break with 50 miles on them and others with 125k on them. Problems have NEVER been related to fluid temperatures or fluid break down.

We are at the point where we can't convince our customers to take off their trans coolers or not to buy one, we often hear the response "well, it can't hurt" or "I'll just play it safe" Wrong! Transmission coolers have many down sides. The tranny cooler is especially dangerous and here's why: We have had to rebuilt more than one tranny due to a failure of a tranny cooler. When your cooler leaks it can cause very serious problems.

With nothing to gain and a lot to lose, you can see why we are so strongly opposed to tranny coolers. Even if the cooler doesn't fail you are adding weight to the car, costing yourself money and blocking some of the airflow to the main radiator which in turn makes the car run hotter costing you HP. If you have a car in a very hot climate or car with a turbo kit, we suggest our oversized radiator to properly take care of the heat issue."

From RegalGS.org:

"I installed the GM cooler 10 plus thousand miles ago along with the Thrasher shift kit. (second setting) I'm a bit "old school" when it comes to these things. I figured if the cooler is on the Police Impalas, it would work with the GS trans nicely. Further, I do have a hitch on the car and haul a small trailer on occasion. For me, I feel more comfortable in using a cooler.

However, during the installation, I double clamped the lines and triple-checked for leaks. There were no leaks and the installation worked great for a while...until...on a WOT jaunt up a back road on my way to an appointment, I noticed a bunch of smoke behind the car. I stopped and looked under the car and noticed fluid pouring out of the front of the car. I thought it was antifreeze and traveled another two blocks to the appointment where I finally opened the hood. FIRE! I carry a fire extinguisher in the trunk and the fire was put out quickly. There was no damage from it either, thank god!

It turns out, one of the "double clamped" lines blew of the steel line and sprayed trans fluid all over the exhaust manifold. Fortunately, I was two blocks from the dealer. Still, I had it towed, I didn't want to risk more fire and a bad trans. The dealer replaced the lines and flared the ends so the re-clamped rubber lines wouldn't come off again. Just a little story of my experience."

So far, we have seen none of these problems at Riviera Performance, but I don't think everyone needs to run a cooler. As long as the trans is functioning properly, and fluid is changed ever 40k miles or so, you should be fine. I think the shift pressures are really high on these engines (up to 96 PSI), which does create concern for lines bursting. However, I know it can be done correctly by someone who knows how.

Personally, I will probably run a cooler in the future, simply because I've noticed a correlation to lower performance and higher KR when the trans fluid temps are above engine coolant temps vs. when below.

Wow, the third story is scary indeed - and I've seen other cases of blown transmission lines causing fires. That stuff lights up easy when it sprays out under pressure onto hot exhaust manifolds.

Always use fittings with hose barbs to the rubber - don't slip rubber hose over steel lines without a flare at minimum - and I prefer a compression fitting with a hose barb on the other side if I'm connecting to a smooth steel line. You can't be careful enough in this situation.

Some random information I found today. Just food for thought:

Transmission fluid cooler can cool too much
By Paul Brand, Star Tribune
Last update: November 7, 2007 - 5:03 PM

Q: I have a 2002 Chevy Blazer Xtreme with the 4.3-liter engine and automatic transmission. I use the truck to tow my Austin Healey on a trailer to vintage-car racing events.

For towing, I added an aftermarket transmission-oil cooler, and it seems to work well. Is there any need to cover the cooler in winter to prevent the transmission from running too cool? I have been towing in third gear because I understand towing in overdrive will overheat and stress the transmission. Is that always true, or is towing on a flat freeway OK?

I changed the transmission fluid and filter when installing the cooler and used Dexron VI fluid, which replaces Dexron V. How is that different? Is it synthetic?

A: The installation instructions for most aftermarket transmission coolers suggest "plumbing" the cooler "in series" with the cooling chamber in the radiator by connecting the cooler into the fluid return line from the radiator to the transmission. Plumbed in this way, transmission fluid is pumped from the transmission, through the cooling chamber in the radiator, through the aftermarket cooler, then back into the transmission. This is the most effective way to keep transmission fluid temperature under control -- meaning in the range of 200 to 230 degrees -- in extreme conditions.

A quick look at the flow of transmission fluid illustrates the benefit of the extra cooler. Hot transmission fluid, perhaps above 250 degrees, flows from the transmission through the radiator where it is cooled by 190-230 degree engine coolant -- not a great deal of cooling effect from only a 20- to 60-degree difference in temperature. But as the fluid flows through the aftermarket cooler, it's cooled by ambient airflow with a temperature differential of 200 degrees or more. The greater the temperature differential, the faster heat is dissipated from the fluid.

But what about winter? If ambient air temperature is extremely cold, the fluid-to-air cooler may overcool the fluid. There are three ways to deal with this. A number of newer transmission coolers feature a self-regulating characteristic. When the fluid is thick or viscous because of cold temperatures, it will flow only through the larger-diameter upper tubes and plates in the cooler, limiting the amount of additional cooling effect. As the fluid warms up and becomes less viscous, it flows through the smaller tubes and plates for additional cooling.

Or you can plumb the cooler so that the fluid flows through the extra cooler before it flows through the cooling chamber of the radiator. In this scenario, the fluid can actually be warmed to normal temperature as it flows through the radiator chamber, a useful benefit in sub-freezing temperatures.

Or you can cover the extra cooler to limit airflow and cooling effect.

The logic behind towing in third gear rather than overdrive is a question of available engine torque and fewer shifts. If the vehicle delivers enough power to operate in overdrive on flat roads without frequently shifting in and out of overdrive, leave it in overdrive for best mileage. In hilly terrain or if the transmission wants to frequently downshift out of overdrive, shift down to drive until you're on flat ground again. There's absolutely no harm in driving in Drive, and the torque converter will still "lock up" to maximize fuel mileage and minimize heat buildup in the transmission.

As for the new Dexron VI transmission fluid, I found a technical article from Kendall Oils that describes the benefits nicely.

"It is formulated to provide improved oxidation stability, shear stability, friction durability and foam resistance compared with earlier generation Dexron fluids to help ensure long service life, better performance in extreme conditions and consistent shift performance for the life of the fluid. It is particularly recommended for use in new GM six-speed automatic transmissions, and is fully backward-compatible with older GM automatic transmissions."

link: http://www.startribune.com/cars/11355081.html

I have just installed a hidden reciever hitch on my riv, and will be towing my Vstar 1100 from Orlando to Miami and back maybe 2 X a year. The bike and trailer weigh less than 1000 lbs, should I have a trans cooler installed??

That's a pretty long drive. You might be ok a few times, but I would install one if doing this on a normal basis - a small one doesn't cost much, and provides you with some assurance that it won't get too hot in the FL sun. Whoever installs your cooler, make sure they are aware of the very high trans fluid pressures our engines create (96psi). May require special hose connectors that won't slip off or fail under the stress.

AA wrote:

That's a pretty long drive. You might be ok a few times, but I would install one if doing this on a normal basis - a small one doesn't cost much, and provides you with some assurance that it won't get too hot in the FL sun. Whoever installs your cooler, make sure they are aware of the very high trans fluid pressures our engines create (96psi). May require special hose connectors that won't slip off or fail under the stress.

I had one installed at U haul yesterday, they seemed to do a good job, used normal hose clamps. I wish I had known about the high pressure thing.....maybe ill check into getting the hard lines flared where the hose meets then install double hose clamps just to be safe, think that will work?

Always double clamp transmission lines. The pressure is too high to risk a single clamp IMO. Where you put the clamp depends what style of nipple they used, if it's just a flared end tube, or a real hose barb.

Surprisingly, many installation instructions (including B&M), advise that you not double clamp. I think Jason's write-up mentioned the same. The reason being, putting two clamps next to each other can create a line of stress in the hose, between the clamps. As the clamps heat and cool over time, they can cause the hose between them to crack, kind of an 'Indian burn effect'.

Here's some info I found in the Allpar forums:

"

Quote :

I know this is locking the barn door after the horse ran away but...Put double hose clamps on all those external hose line fittings and the problem won't happen again. Easy enough when you get up to speed after your move. Good luck with getting it going again, your new job, and finding a good place to live.

I'd be careful with that - the instructions on the aux trans cooler I put on our 96 specifically said do not double clamp it - and I found out why. Its actually happened to me twice - yes twice - on our 96 GV - you can find some related threads if you look. At one point after the first time I double clamped it - well after a while the hose between the clamps started to crack and deteriorate - I assume due to movement from expansion and contraction between the two clamps. So then I went to a single high pressure EFI hose clamp - which is what was on the hose when it let go the second time (both times were after a long trip to Florida from Ontario). I think the second time I just did not get the clamp on right - I think I might have had it right at the end of the hose with no hose protruding past the clamp - the clamp was sitting on the fitting after the hose slipped out. This is the only vehicle I have had this trouble with - and I have put on aux coolers on many others with no issue - not sure what it is with this one..."

Link: http://www.allpar.com/forums/index.php?showtopic=98919

Maybe the best solution is to use double clamps with an extreme duty hose, or insert a lining between the clamps and hose to protect from cracking?

Probably a bit overkill, but this might be just the kind of security we need for this job. It's not cheap, but compared to converting to AN or NPT fittings and hoses, I bet it's a reasonable option:

http://www.jegs.com/i/Earl%26%23039%3Bs/361/350606/10002/-1

Earl's ProLite 350 Hose detail:

Okay, I'll give you that. If you overtighten old school clamps you could have a problem. But I've had issues with single clamps and never with double clamps. It depends on the hose barb.

And using the high pressure EFI style clamps will help and make a big difference. Those weren't readily available a few years ago, and aren't what usually comes with the installation kits in the tranny coolers.

So using a proper hose barb and a good single clamp should be okay. But I'll still double clamp mine.

Thanks for the input, Derek. I think double clamping is the way to go, as long as we use a quality hose with a durable jacket.

I ordered a cooler last week. I've driven so long without a cooler, and I didn't think I really needed one, but now that I'm towing the trailer more often, and with the hot summer coming, I have plans for autocross and a possible fun day on a road course. This is not normal driving, this is long term high-load operation with no TC lock-up, exactly what makes trans fluid temps rise to unsafe levels.

Took a long time to pick out the right one, but finally decided on a Tru-Cool MAX cooler. The main reason I picked it is the shape - very long (23"), thin (.75"), and not very high (4") - fits almost perfectly at the bottom, in front of the AC condenser. This is the area below the bumper where the air opening is. I know putting it behind the bumper provides the best shielding against rocks, but I read at least one source saying the best cooling was achieved by placing the cooler fins in an opening for the "ram air" effect.

The Tru-Cool MAX comes in 3 sizes. I went with the smallest size, a 22,000 BTU unit. This is still a serious cooler, more than double the cooling efficiency you get with most compact coolers, it's recommended for trucks pulling trailers with gross weight of 24,000 lb. The instructions warn not to run a Tru-Cool MAX under 32ºF ambient without using a thermal bypass unit, which I also ordered. The price of the cooler kit was $81.04 and the thermal bypass was another $30.32, ordered at bulkpart.com: Link

Received my kit only 3 days after ordering, along with 3 ft of JEGS Pro-Flo 350 ($20) picked up separately. This hose is a high pressure type with nylon braided jacket for light weight and flexibility, very similar to Earl's Pro-Lite 350 hose. Here is the kit (click for larger view):



I haven't installed it yet, but have tried fitting under the front bumper and it fits perfectly in the lower intake, taking up a large portion of the opening. I will probably install in stages; will post up more pics as time permits.

I like the looks of that kit.
If you would document the install it would be greatly appreciated.
I'd like to do the same. Except I have a problem with spending almost $7.00 per foot of hose. I know it's good quality hose and all but that isn't right. I'll have to check the local Hydraulic Repair place down the road for the price on reinforced hose for this application.
I do like that cooler shape and the fact that you found the thermostat for it as well.

The Tru-Cool comes with 3 ft of standard high-pressure hose included with the kit. It's decent stuff, but I chose to upgrade the the JEGS stuff because I don't want to take any chances. Our trans fluid pressures are unusually high - the service rep at JEGS didn't believe me when I told him 96 PSI, he guessed 45 PSI max.

The JEGS hose is good to 350 PSI, but a telephone tech rep told me it would support up to 1000 PSI, at temps above 300ºF. It's a pretty stout hose, yet it's thinner, much lighter, and more flexible than the one included in the Tru-Cool kit.

I also might be jumping on board here. I am right in the midst of buying a trans cooler too. and that kit looks nice. What better way than to get one that someone has already test fit the core for a riv!

Anyone think any screening would help for rocks and such? Maybe an aluminum frame that fits over the core....

You may want to wait and see how I mount it before you follow suit. The path I'm probably taking is to mount the top corners to the molded plastic surrounding the radiator. The bottom corners are hard to mount, but they might be able to bold in with the X-brace up front. Or, I might just fit the flanges under the plastic lip of the lower moulding and mount the top brackets under tension. Could also zip tie to the two vertical supports for added security.

As for the rocks and debris concern, I looked at the AC condenser in the exact location the cooler is going, and it seems to have held up pretty well over 200k miles.

For mounting I can make anything! (the joys of a prototyping shop)

The rocks are a concern for me because there are dirt roads everywhere where my parents live, so when I go visit them.. rocks and crap everywhere...

Mounted the cooler today, took less than an hour. I used some large, flat washers to fasten the brackets, and zip ties secured to the x-brace members. I did not bolt to the bottom flanges of the cooler; they are tucked into the molding edge. The cooler is very solid, doesn't move at all - need to drive around a few days and see how it goes.

The cooler is shifted slightly to the driver side to allow clearance for the hose connections.

that sweet.