Grit dog wrote:
blt2ski wrote:
BUT, if you're doing freeway miles, no problems. Doing city driving pulling local grades in the 15-25+% relm. Then the tall first year of the th400 and 4l80 get heated up really fast and quick. Whether you have an external cooler or not. That's the issue I have towing when I tow. If it's not geared over all low enough, Ive stalled many a truck out, even a 12k loaded 454, 4.10 th400 geared rig.
Marty
You actually should buy more powerful trucks rather than having to calculate whether x truck will pull x weight up x grade before you leave the yard.
So a 454 back in the 80s was not the most powerfull truck in a GM pickup? if not what was? I learned the hardway, having a powerful 235/385 truck, with incorrect trans gears, rear gears, does not make a good towing rig at times. Hence why the TH400 is not a good trans, has the tallest first gear of ANY 25/35 series auto. Hence why my smaller engines with manuals could pull steeper grades vs the higher HP torque ones with autos. TOday the autos allow one to have overall low gearing better than my 88 and 89 454 rigs. I've even stalled out my 05 dmax on a short grade up on the pine lake plateau. Glad in that case I had 4lo to work with. That is the only time I pulled stalling it!
so in the end, it does help to understand what a rig with a given gear set, motor will actually do, vs trusting manufacture warranty ratings. My 6.5TD with a nv4500 would not overheat, vs those with 4L80E;s. I pulled local freeway grades faster, yet had a 2000 lb lower gcwr......all because GM did not want to worry about warranty on the clutch, not that they gave it a warranty..... Then again, the TH400 and 4l80 use up 40-45hp, vs NV at around 25HP, Allison in the area of 60 hp from flywheel to output shaft. A Big powerful motor is nice, IF you have the correct gearing behind it. If not, you're screwed! Especially at low speeds.
Marty