I have a 2003 Blazer LS 2DR. And was putting a Class 3 hitch on it tow a u-haul trailor...I have to tow itthrough the mountians about 9 hours drive..Will this be a problem..The U-haul site says i can tow up to 5000lbs...

 

A Class 3 will handle any weight a Blazer is rated to tow. If yours is a 2wd 2dr (non-Xtreme) you can tow 5700lbs. If its a 4wd 2dr, 5400lbs (ZR2 4600lbs).

 

Make sure you put a trans cooler on it also! I tow about 2000 pounds in the summer, mostly on flat roads, and my trans temp goes up to 195 degrees, and I have the biggest cooler I could find installed onto my Blazer. So you can imagine what kinds of temps you will get if you have no cooler, and heat is the #1 killer of an automatic transmission!

 

And do not use overdrive. It will drive the temps up very very fast!

 

Check this thread also https://blazerforum.com/m_127088/tm.htm

 

Yeah, as Rob said, check the other thread. OD is perfectly fine for towing provided that the tranny isn't hunting for the proper gear. If the TC is locked, you won't notice any additional heat generation.