[larrybuck]

I have an '85 Suburban 6.2 D w intro...ed trans. We all mostly know with a car anyway the token advice not to use the OD at lower spds w hills. Of course as ecomodders, a lot of us are pushing the envelope for higher mpg. I am always short shifting my CRX, and rare is the time when I'm not in 5th by 30mph. I also try to skip 4th gear in certain down hill starts.

I am currently unemployed: I use the Sub. less than 1% of the time. With a 40 gallon tank, I have never filled it, and ONCE I did a 1/2 tank guess (mpg) trip w very good cheerful #'s ( I believe 27-30+ mpg poss. w some airdam, side skirt(under) work) Not bad for a fact. K model...thankfully a past owner put on manual hubs.


I have towed cars a couple of times, and it has done very well, in its only 125hp way.

The meat of what I'm trying to discuss here, is more Interstate (mostly 6% or less grade hills, etc...) Obviously, in urban/suburban ( no pun intended) areas; towing is stuck in the old classic 3rd gear ( that SLIPS in all AT's) I try to min. that mpg. wasteland as much as poss. In my freeway towing so far, I've towed a 2,600# vw Quantum wagon (want to make D powered!) on a typical tow dolly pretty well at 45-50mph in 4th on the freeway. With my low HP; obviously, I'd change down to 3rd myself, if it were clear I was going to be 30-35mph..ish going up the next hill.

The Sub. not towing wants to upshift itself into 4th at about 37mph. With what I have towed # wise; I figure I could do a cross country type trip being in 4th 97 % of the time attempting a general 50 mph average cruise speed.

NOW; we change the picture: This is a K10 Suburban, not a K20! What if I now add a 26ft. enclosed Wells Fargo enclosed trailer w that 2,600# car inside? Less aero, and more weight. Could I still hope (dream?) to achieve the above paragraphs mojo staying in 4th maybe 89-92% of the time? I've not ever pulled that much weight with an AT before... always w a stick! That was w a '69 Ford F250 w 360 V8 averaging 11.5 mpg towing cross country at 40mph flat land towing cruise.

What mpg. should I expect? Is the GM setup strong enough? I've read that Suburban's like mine can be rated to pull a total of near 13,000#'s! Most of all the near vintage to mine, are all AT's. Could a stick trans. from a D PU swap onto the 6.2 easily, and would that be better?

I don't care that my setup is kind of a slug. I like that by itself, near 30mpg highway is there... what do you think I'd get w the bigger tow I've described? If I needed more speed, and more $$$$; I'd probably lean toward a late 80's, early 90's Dodge w Cummings 12V as I hear 22mpg is possible at 70mph towing a 30some foot 5th wheel travel trailer!! How well does a later model Duramax do???

So many questions, and life is so short! I thank you for your responses in advance... and thank one of you who was nice enough in a NICE way to teach me how to PARAGRAPHS here, as I'm still fairly new to computers!!!