Thread: too much stall

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If he could give some feedback with a tach, it could help. A hi stall isn't going to do much before its stall speed, but we may be both right. At any rate, he would sure feel the difference from a set of 4.11s

Originally Posted by firebird77clone

If he could give some feedback with a tach, it could help. A hi stall isn't going to do much before its stall speed, but we may be both right. At any rate, he would sure feel the difference from a set of 4.11s

Tom, I'm not saying that the stall speed of the converter may not be high for your engine's torque band and rpm capabilities, but it's a moot point with the gears in the differentials as there is simply not sufficient mechanical advantage with the tall tires. IMO 4.11's are not nearly tall enough, but to each his own. Pick your desired cruise speed depending on the mix of driving and highway cruise rpm you want, and pick your gear ratio (front & back) accordingly. Now the numbers are based on the assumption of a 700r4, but....

Originally Posted by rspears

I'd probably go at least 4.88's, but 5.13's or even 5.38's are not too much, depending on how you use the truck. Points of reference, consider 70mph cruise, assuming a 700r4 OD, 4.56's turn 1950rpm, 4.88's turn 2087, 5.13's turn 2194, and 5.38's only crank 2300rpm at 70mph. Drop in a pair of new ring & pinions and get that gearing where it needs to be and it'll be a whole new truck. You're gonna love it!!

Good luck with the truck, and if you've got a good 4X4 shop in the area drop in and chat with them about your truck and I'm pretty sure they'll echo what I've told you. I've found our 4X4 shop (the "good" one is an hour's drive away, in Topeka) to be an excellent place to have gears set up, because they're into differentials all the time with off-road rigs, and a good shop will know their stuff. Post some pictures of the bad boy if you get a chance!

I tend to agree with Roger. Installing much higher rear gears would be the first thing to address.

Here is an excellent chart that will help to pick the best gears for the application. With the overdrive trans. and 38.5" diameter tires a 5.38 gear would be "just right" and make the truck much more enjoyable to drive. You'll think you tripled the horsepower!

Be sure to read the notes about overdrive transmissions that are discussed in the text above the chart.

Hope this helps... and post up some photo's of your truck Tom. No doubt it looks great with those big meats!