What is a rommended transmission cooler

I have a 2001 Montana with 171000 miles the the transmission whines when hot and starts to shift hard and I want to add a transmission cooler. Can anyone recommend a cooler?

For the GM mini-vans and their mini-SUVs using 3.4 - 3.5 - 3.6 - 3.9L engines, I would only install the LPD (Low Pressure Drop) design aux ATF cooler. As my 1st choice brand, I would pick Tru-Cool maker. As my 2nd choice, I would pick Hayden maker. Many say Hayden is a clone of Tru-Cool - without the internal temp sensing / fluid re-routing ability. And, I would install aux ATF cooler even if NOT pulling any trailer. Especially if one lives in hot summer month regions. If wondering, my local Transmission Specialist says that all GM mini-vans "run hot". Too hot during the hotter summer months. Thus, he only installs a cooler for 3,500 lbs trailer (for NOT towing vehicles) and for towing up to 3,500 lbs trailers, he installs a aux cooler rated for attached 5,000 lbs trailer. On some charts, the aux ATF cooler sizing range is from 24,000 to 28,000 GVW ratings.

Two aux ATF cooler models I'd recommend for GM mini-vans (and other GM V6 engines) are:

Tru-Cool 4589: http://www.transmissioncoolers.us/Merchant2/merchant.mvc?Screen=PROD&Store_Code=T&Product_Code=4589&Category_Code=trucool-coolers-hd
Hayden 1678: http://www.transmissioncoolers.us/Merchant2/merchant.mvc?Screen=PROD&Store_Code=T&Product_Code=1678&Category_Code=hayden-transaver-cooler

If wondering, the Hayden 1678 installed on my 2009 Montana 3.9L van (which tows a 2,000 lbs trailer a few times a year). Its pictures are:
http://i178.photobucket.com/albums/w251/Spike99-Pictures/Montana%20Van/Aux-Cooler-Tophose.jpg
http://i178.photobucket.com/albums/w251/Spike99-Pictures/Montana%20Van/AuxTransCooler-UpperSupport-2.jpg
http://i178.photobucket.com/albums/w251/Spike99-Pictures/Montana%20Van/SummerRAD-2.jpg
http://i178.photobucket.com/albums/w251/Spike99-Pictures/Montana%20Van/SummerRAD-1.jpg
http://i178.photobucket.com/albums/w251/Spike99-Pictures/Montana%20Van/WinterRAD-2.jpg

Note: Bottom picture shows plastic cover (thick plastic bag) wrapped around my van's cooler for my colder winter months. If living in extreme cold region, I'd recommend wrapping your aux ATF cooler as well. Sometimes, "too cold" is as bad as "too hot". Especially when driving "wind chill" temp change is involved. re: -20C with frontal wind chill can "feel like" -40C/-50C at times. For better proactive protection, wrap the aux cooler - just like humans wear a winter coat during high wind chill months as well.

If your GM mini-van tows trailers, "loads up" with cargo &/or is driven in hot temp climate regions, then install the large size aux ATF cooler - rated for 28,000 GVW - like the Tru-Cool 4590 ( http://www.transmissioncoolers.us/Merchant2/merchant.mvc?Screen=PROD&Store_Code=T&Product_Code=4590&Category_Code=trucool-coolers-hd ) - which is rated for attached full 5,000 lbs trailer. In hotter regions, the larger size the aux ATF cooler, the better. Especially when the RAD is installed most furthest away from the vehicle's air sucking fan.

Hope this helps....

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Also....

If the transmission doesn't shift smoothly when its within warm - hot temp range, its "shift solenoid" may need to be replaced. The 4t65e transmission is known for weak solenoids. Especially when transmission is run "hot" for too long of time period. Many transmission shops can replace the 4t65e's shift solenoids very easily...

Hope this helps as well...

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Is the shift solenoid is the same as the PCM? Where is it located in the transmission?

Is the shift solenoid is the same as the PCM? Where is it located in the transmission?

Lots of pictures at http://helpwrench.com/forums/showthread.php?7-GM-4T65E-solenoid-shift-valve-replacement-TCC-PWM-EPC-1-2-2-3

http://www.automaticchoice.com/Catalogue/4t65e.pdf

Good luck....

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