Towing Issues: towing in second gear, overdrive transmission, temperature gauge

Question
Is it advisable to tow a trailer with a pickup's automatic transmission in second gear? My daughter's riding instructor has a circa 1980 GMC One-Ton pickup. She insists that her small double horse trailer (about 5000-6000 pounds loaded) can only be towed in second. Are 80's era One-Tons that wimpy or is she being overly cautious? As far as I know, the truck's transmission is in good condition. My 2001 3/4 Ton hauls my heavier trailer in drive with no problems at all and poking along the freeway at 40 when we convoy is getting to be a real drag... Best regards, Dave

Answer
A one-ton truck should be easily able to tow a 6000 pound load in high gear, maybe not up a 15% grade, but for sure in most of the flatland.  If the transmission is not an Overdrive transmission, then Third gear is direct drive and the equivalent of taking my 2003 Silverado from OD to Drive, where is is just fine to drive as much as you want.

If the instructor puts it in drive and it instantly downshifts into second, then maybe they are right, but I doubt that is the case.

towing in second gear isn't going to be a problem really unless they are trying to do high speeds, and then the high rpm of the engine will mean even less MPG (hard to believe!) and major wear/tear on the engine.

Have them try putting it in Drive at 35 0r 40 and see if the truck is able to pull and accelerate without kicking down.  They will have to accelerate gently to do this test, but if it will go up to 60-65 or so in drive and hold that speed on the level without kicking down all the time, then they should be just fine.

As always keep an eye on transmission fluid, and keep it fresh.

Also, if they install a transmission temperature gauge that would settle the question for sure.  

Don