2003 3/4 Ton Suburban, Trans Temp Wiredness

[jjjamn]

Hi, I have a 03 Suburban that I use to tow with quite often.

The Suburban has 13000 miles and for the last 12000 miles my transmission temp guage has never gone over 150 even when towing.

Last week I towed about 300 miles and when I went to head home, about 10 miles into my trip my transmission temp was at 250.

270 is Red line and the motor shuts off. It just stayed around 250 the whole way home.

The next morning I heading down to the dealership and I was at 200 within 5 miles. Again I have never gone above 150 since owning the suburban 12000 miles.

The dealer said my Torque Converter had gone bad and that was the cause for the transmission getting to hot.

I just picked the suburban up after getting a new Torque Converter and in 5 miles I was at 200 again.

Any Ideas....... ?????

I have checked 2 other 03 Suburban 3/4 tons and both dont go above 150... EVER....

Thanks in advacne for any suggestions