Going to tow my boat on major highways Thursday for the first time with the hummer. My question is, should I keep the auto tranny in 3rd or in drive? It's going to be about an hour and a half drive at 65+mph. Whats better for the trans, to stay in a lower gear and having the revs high or to keep it in a higher gear and have it downshift alot to keep up with traffic? Any suggestions?

 

If it's mostly flat, leave it in "D". If you are in hilly terrain, shift into "3". If it seems to hunt for the right gear, downshift it into the lower gear. If "D" feels excessively heavy for the load, downshift. If the temp seems to keep getting closer to the H, downshift and go easier on it. With these guidelines, I'd say you cant go wrong.

 

I dont understand everyone problem with the H3 running hot, it has to be a thermostat issue, I pulled a loaded 15 foot trailer from Buffalo NY to Wichita KS, without the temp gauge going over half,

 

I agree keep it in drive going up hill put it in 3rd.

 

This sunday i drove around in the city going to fathers day at my fathers cemertery and my girlfriend fathers cemertery drove in traffic in the city stop and go 98 deg out ac on temp never move past the half way mark.Oh and it was at least three hours of running time

 

thanks guys, I'll try it. Never towed the boat with an auto before. I'm not concerned with the engine getting hot, I'm concerned with the tranny getting hot. On a trip to Maine two years ago my buddy was towing with his grand cherokee 6 cyl. Somewhere in Mass. he blew the trans cause it was running so hot.

 

usually if you have a tow package from the factory you should be all set.

 

I thought the tow package was just the hitch/wiring. does it come with a factory tranny cooler?