Towing in 3rd gear on a 1300 mile trip
I have a 1997 GMC k1500 Z71 5.7 liter with 20000 miles and a 4L60e transmission with only 2000 miles, I will be towing a 3000# dry weight TT from Louisiana to Colorado. I plan on breaking the trip int...
Forum Discussion
parker.rowe wrote:
I tow with a similar vehicle, in my signature. Mine has 132K miles. My camper is a bit heavier though. (6500 gross, around 4500 dry IIRC)
I always lock it in 3rd. With the extra weight and wind resistance it kicks in and out of OD, or unlocks the converter in OD, whenever it hits a hill. I did a test where I ran a leg in overdrive, with the cruise set, and let the computer decide. Trans temps were ok, but my gas mileage was actually worse then just locking it in 3rd.
Does a great job in 3rd. With 3.73's and 33 inch tires I am usually between 2500 and 3000 rpm depending on speed. Anything over 60 and the gas mileage starts dropping.
I feel the Vortec 5.7 is much better suited for towing than the Vortec 5.3, especially with a 4 speed auto. Both are great engines though.
I got 8.5 mpg on my last trip hand calculated. Not bad for a 20 year old gas truck towing a brick at 55-60mph.
I think I agree with you one the 5.7 vs. the 5.3. The 5.3 in the Burb, at least the first gen 5.3, gets really decent gas mileage for a big vehicle. But, it's not a monster tow-er. From experience I'd say that the old 350/5.7 felt like it pulled better. With that said, over the period of a year, I'd rather feed the 5.3.
