Do I need a transmission cooler for towing?
 

I have a 2001 Blazer RWD with the factory towing package.
Next summer I want to tow my jet ski or my 17 foot boat.


I recently installed a new AC Delco radiator and thermostat. The temperature is a steady 190 degrees in hot and cold weather.
I added the Dorman transmission pan with a drain plug. I drain and refill the transmission fluid every other oil change and will change the trans filter every 25,000 miles.
I use Mobil-1 synthetic multi-vehicle formula similar to Dexron III.
The trans shifts firmly and has zero leaks.


So the questions..
1. Should I add a transmission cooler?
2. If so, should it be added to the upper or lower trans line?

You have a trans cooler in the radiator.

You are changing the fuild waaaaaaaay too often

I tow a 15' boat with my 98 blazer ( Blue Blazer, Blue Boat) looks so cool. It has 188,000 on it.I went to a transmission mechanic ( that's all he does) and said I want a flush n fill I'm going to tow a boat. He told me he would but I may never make it home. The new fluids have way more detergents in them, and the expansion rate faster.( Older fluids expand when reaching a certain temp) The faster expansion rate and high detergent would surely blow out any seals and gaskets already settled in. Its ok to add new stuff when needed because its a gradual addition.Yeah so I wouldn't suggest over changing your fluid if it works don't fix it. So been towing this boat with my ole blue for over a year no problems.

Towing a jet ski you should have no problems. Depending on the weight, terrain and temps when towing the boat an aux cooler may be a pretty sound addition.

Heat kills a transmission more than anything else. Engine temp is no indication of trans temp.

I totally agree with u changing it waaaaay to often!!!!! On another note, the trans cooler in the radiator is a joke!!!! I bought the biggest cooler available at advance and installed on mine, btw use both of the hardliners coming from the trans...... For optimal cooling:icon_photo:I believe Captain Hook has a thread somewhere on here regarding aftermarket trans coolers????:icon_cold:

I agree that I may be changing the fluid too often. Maybe every 4th oil change or so and the filter every 25,000 miles. I have done this on all my vehicles and have never had a transmission go bad or leak even after 200,000+ miles. Usually I get 160,000 miles on my vehicles and sell them because they start to rust, not because of mechanical problems.


The 2001 Blazer is mostly a garage queen for wifey and will rarely see salt. So I may keep this one to very high miles.


I think next summer I will add an auxiliary transmission cooler in series with the existing one.

You should always add an trans cooler when towing anything. The internal cooler in the radiator is basically just a tiny little coil in the radiator tank ..does next to nothing. people who know automatic transmissions will tell you get the most cooling you can get to the tranny. The correct way is to leave the transmission line from the tranny to the radiator intact. Take the outlet side of the radiator and run it to the new cooler. Take the outlet of the cooler and run it back to the return line of the tranny. Good brand name coolers will have all the proper line and fitting adapters to do this without having to cut up the factory trans lines. Again, from the tranny to the radiator to the cooler back to the tranny. Most guys just bypass the original cooler in the radiator but the purpose of doing it this way is the engine coolant helps warm the trans fluid on cold days to get the tranny upto proper operating temp, which is important also.