I put this thread in IMHO, because I’m looking for opinions. On U-Haul’s web site at http://www.uhaul.com/hitches/transmission_cooler.html they claim it’s a good idea to install a transmission fluid cooler if you’re going to be doing any serious towing. I’ve got a 1993 Plymouth Voyager LE (w/ 3.3L V6 engine) that I want to add a trailer hitch to so I can tow the boat I’m planning on buying soon (18’, about 2500 lbs, plus trailer). I’d like opinions on whether or not this transmission fluid cooler would be a good idea. It’s not terribly expensive ($81 plus installation). Is this really going to save my transmission, or is it just something U-Haul likes to sell people to make them feel better and take more of their money?
Since you’re looking for HO’s, here’s mine. For the money, and piece of mind, I’d do it. You don’t mention how far you’ll be towing, or over what type of terrain, but being that it’s a boat, I’ll assume you’ll be using it in the summer, when vehicle temperatures normally run hotter. The extra weight of the boat/trailer will not only tax the transmission more, but also the engine. Currently, your transmission is being cooled by the same radiator that’s cooling your engine, and that’s a lot of work. It just makes sense to me to split the load over two separate coolers than to have one doing all the work. I believe I’d do some comparison pricing before I’d let U-Haul do the job, though. You could probably get it done cheaper by an independent.
With my '89 Dodge Caravan, I had the 3.0 liter V6, and it typically ran cold all the time. I used to tow my yamaha boat, I forget what kind, but it had 2 1100cc waverunner engines in it, and on hills on really hot days, it would run hot. So I would recommend the tranny cooler.
Automatic transmission fluid deteriorates with use, and especially with heavy use, such as towing and/or driving in mountainous terrain. Heat is the major factor. An auxilliary transmission cooler, properly installed, is a good idea. It’s money well spent.
Typically, the factory transmission cooler is inside one of the radiator tanks. It is not exposed to airflow, but is surrounded by and cooled by engine coolant, which is about 200 degrees Fahrenheit on a warmed-up engine. As you can imagine, tranny fluid gets mighty hot if you can cool it down with 200 degree liquid. Having an auxilliary cooler exposed to outside air–even 100 degree air–is a big help.
For most typical situations, a tranny fluid change is recommended every 2 years or 30,000 miles. Automatic tranny rebuilders, who spend the day dealing with the results of fluid breakdown, often change the fluid in their personal cars at half that interval.
If your tranny is a 4-speed (overdrive), it might be wise to use “D” (automatically shifts up to 3rd gear) rather than “O” (automatically shifts up to 4th gear). Many 4-spd. automatics use a sturdier internal power path in Drive than in Overdrive, and will hold up better to the mechanical strain of the extra load from towing. This is separate from the fluid issue.
Consider having a reputable (as in, NOT a nationally advertised chain) transmission shop provide and install the cooler. These folks are specialists, and could also provide good information and advice. If the shop is a member of ATRA (Automatic Transmission Rebuilders Association), that’s a good sign.
I’m an auto repair professional with nearly 30 years experience.
Thanks, folks. This is exactly the sort of feedback I was looking for. Since everyone seems to think it’s a good idea, I think I’ll have a transmission cooler installed before I start towing stuff. There’s a small, local transmission rebuilder shop around here that does good work, so I’ll see if they can do it for me before I resort to going to a U-Haul affiliated shop.
superbee - you were right, I’ll be towing the boat in the summertime, for maybe as many as three hours at a time in the hot summer sun. I shouldn’t be encountering too many hills, though.
Gary T - I don’t have overdrive, but I’ll keep your advice in mind if I end up towing with a vehicle that does have it.
I had to replace the transmission on this vehicle once before to the tune of $1700. If I can spend $200 for a transmission cooler and avoid that, I’m more than happy to do it. Thanks again, folks.
There is no way that 1993 Voyager is still running 15yrs later.
I’ve heard a few people recommend it even if one is not towing anything, it should extend the life of the transmission.
The automatic transmission’s biggest enemy is excessive heat. It degrades the fluid, which is much more highly specialized than simply oil. It has corrosion inhibitors, friction reducers, friction enhancers, and a bunch of other additives that improve it’s performance. Most, if not all, of these additives will degrade when exposed to elevated temperatures. In addition, the elastomeric (rubber) seals will age much more quickly at elevated temperatures. While these materials do fine around 200F (normal operating temperatures), the temperatures can spike to well over 300F when pulling a heavy load.
Now, 300F will not break your transmission in one day. It will shorten the life considerably, however. Neither the fluid nor the seals will “get over” the exposure to the higher temperatures. The fluid is relatively easy to change, but to replace the seals calls for a complete overhaul of the transmission.
In my opinion, cars with automatic transmissions should have a temperature gauge for the transmission fluid temperature. I can understand that in days gone by, this would have been an unneeded expense that would have had rather limited (if any) utility. But, today’s automatic transmissions are much more complex, as are the fluids, and the cost of instrumentation is mind-boggling low.
I suspect that the subject 1993 Voyager, already pretty old at the time of OP, is probably rusting in a junkyard someplace (or resurrected as assorted steel in dozens of other vehicles).
How on Earth did you choose to resurrect this particular zombie? 
Vanished spammer.
Ah, ok. I suppose I should have guessed that.
Carry on. Although I doubt OP’s van needs the transmission cooler now.
Interesting tidbit, I have a 2004 Ford F150 that I bought used and I found out it was actually cheaper to buy it new with the tow package than to buy it without.
Don’t you mean “varnished spanner”?
Looks like my post got vanquished too! oh well.