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BETRAYED BY MY K5/Lazy Heffa

GalDemSuga said:
Sounds like another $2000 in mods here, the wife isnt gonna fall for this. She already hates my girl because I love no other truck like this one.
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I just bought some 3/4 ton axles, and called it a day. They will come with lower gears, and if you get them off a chevy they will bolt right in. Maybe some minor mods to the rear end. But best of all its only around $600 to $750 for a used set. I just got a set, 14 bolt rear and 44 3/4 ton front for $600 in Ca. Plus a lot of extra like spacer for a doubler 6" front lift springs so on. Just saying maybe your wife would be ok with that cost, and if you ever wanted to go bigger than 35" in tire size you will be half way there. All I hear about the 14 bolt is that it's bulletproof. But I'm no expert.:dunno:
 
Definitely get the 4.10's and get your self a tranny gauge so you can watch your temps in the future and change your driving to accommodate it rather than break down while towing which really sucks :(
 
Try to get the brand name.
Some of them are cheap made and noisy to boot.
Also, make sure that you get all the opinions from the experts around here as to the ratio.

Going from 3.73 to 4.11 will make a difference for sure, but you can go deeper. They make a 4.56 that will use the standard parts.
I suspect that it is too much though.

If you go farther, like a 5.38, which I DO NOT recommend, you have to have a notched cross pin for it to fit.

Shame it is not a Ford 9 inch. Not because its a Ford, its just they are much more convenient to set up.
If you could borrow some gears, you could bolt in a 4.11 setup, drive it around for a few miles, come back, pull the third member, bolt in a 4.56, and try it.

And still have time on a Saturday to put your old gears back in to drive until you get the ones you liked ordered.

I know there are bound to be better places to get gears, and someone will give some links, but you can always browse Randy's place.

http://www.ringpinion.com

I am quite sure that there are folks here that will have bad things to say about him, but everybody who did business with him that I know of had good service.

Course, its been a while, he may have sold out or died. His business is still going strong though.
 
OK, just for fun, I ran some numbers through an RPM calculator.

I used 3.73 for the gears, 33 inches for the tire, and 1 as the transmission ratio.
Yours in OD is .70, but its not recommended to tow in OD.
I am assuming that your transfer case is also 1.

3.73 = 2469 RPM

4.11 = 2720 RPM

4.56 =3016 RPM

All at 65MPH.

So, it looks like 4.11 puts it in the top of the preferred band, and 4.56 is a little too much.

But, you would love the way it handled with 4.56s. Off the line would be like night and day.
Of course, your top end speed would not be anything to brag about.......
 
4.56's...minimum. Still only 2270 rpm at 70 mph, and your tranny will thank you. It'd be 2550 rpm at 55 mph in drive. You are towing in drive and not overdrive right? Going from 3.73's to 4.11 is a waste of time and money...not enough difference to be worth the effort.

Think of riding a mountain bike with 20 gears to choose from. Your legs are the transmission. put it in the highest gear and try and pull a small grade...tell me how bad your legs are burning at the top, if you can make it to the top. Now drop three or four gears and try it again, and not only will you make it, but your legs won't be burning. Good deep gears do that for your tranny. Less effort, less heat = better towing, better reliability.

On the other side of the equation don't forget those gears multiply torque at the wheels. Lets say your 350 makes 300 ft/lbs of tq from 2000 to 3500 rpm. With 3.73's there is 1120 ft/lbs of tq going to the wheels, with 4.56's it'd be 1368 ft/lbs. Very oversimplified, but you get the idea.

Rene
 
tRustyK5 said:
4.56's...minimum. Still only 2270 rpm at 70 mph, and your tranny will thank you. It'd be 2550 rpm at 55 mph in drive. You are towing in drive and not overdrive right? Going from 3.73's to 4.11 is a waste of time and money...not enough difference to be worth the effort.

Think of riding a mountain bike with 20 gears to choose from. Your legs are the transmission. put it in the highest gear and try and pull a small grade...tell me how bad your legs are burning at the top, if you can make it to the top. Now drop three or four gears and try it again, and not only will you make it, but your legs won't be burning. Good deep gears do that for your tranny. Less effort, less heat = better towing, better reliability.

On the other side of the equation don't forget those gears multiply torque at the wheels. Lets say your 350 makes 300 ft/lbs of tq from 2000 to 3500 rpm. With 3.73's there is 1120 ft/lbs of tq going to the wheels, with 4.56's it'd be 1368 ft/lbs. Very oversimplified, but you get the idea.

Rene
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Rene, not doubting you at all, just wondered what you used for a calculator. My numbers are way different.
I have been using that one every so often, and if there is a better one I'd like to know.

Of course, we may be using different size inputs. Check my numbers above. I may have the tire size wrong.

I agree that the 4.56 would do more for him than a 4.11, but my numbers put the rpms up pretty high at 65
 
having the OD and 33" tires I would go with 4.56's if you do a swap.

Id watch craigslist or the ads on here for gearsets or maybe even axles instead of regearing.
 
I was towing in OD:o
Movin on:) How will 456 respond when I'm not towing. I usually drive 80plus miles an hour.

tRustyK5 said:
4.56's...minimum. Still only 2270 rpm at 70 mph, and your tranny will thank you. It'd be 2550 rpm at 55 mph in drive. You are towing in drive and not overdrive right? Going from 3.73's to 4.11 is a waste of time and money...not enough difference to be worth the effort.

Think of riding a mountain bike with 20 gears to choose from. Your legs are the transmission. put it in the highest gear and try and pull a small grade...tell me how bad your legs are burning at the top, if you can make it to the top. Now drop three or four gears and try it again, and not only will you make it, but your legs won't be burning. Good deep gears do that for your tranny. Less effort, less heat = better towing, better reliability.

On the other side of the equation don't forget those gears multiply torque at the wheels. Lets say your 350 makes 300 ft/lbs of tq from 2000 to 3500 rpm. With 3.73's there is 1120 ft/lbs of tq going to the wheels, with 4.56's it'd be 1368 ft/lbs. Very oversimplified, but you get the idea.

Rene
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Ok, I think I found the discrepancy. Rene, I think did the first numbers in OD. That agrees with my numbers.
So, if you go with 4.56, and tow in drive, not OD, it will be about 3016 at 65. Not too bad.
At 80, in OD, the rpm is a reasonable 2600.
 
GalDemSuga said:
I was towing in OD:o
Movin on:) How will 456 respond when I'm not towing. I usually drive 80plus miles an hour.
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There is the issue, or at least a major contributor. Even the owner's manual will tell you not to tow in OD. That is the #1 easiest way to nuke a 700R-4...

Tow in drive. Slow down when you're towing, remember that trailer has all the aerodynamics of a barn and moving that air 1 mph faster requires exponentially more power. 55-60 mph, let the rest of the world pass you.

Better gearing helps a ton. 4.56's will be wonderful when you're not towing...should give you a ton of snap and response you never had before. Plus it'll keep you at a better speed when towing.

Fordum, I am old school, I use a calculator to figure rpm's for various gears and tires.

speed (mph) x diff gears x OD (if applicable) x 336 (for lock up auto or manual tranny, 355 for non lock up auto) / true tire diameter.

The cool part is plenty of variations can be dropped into te mix, and I don't need to be online to do it. :D

Rene
 
I will heed the good advice:) Thanks to both you and Fordum

tRustyK5 said:
There is the issue, or at least a major contributor. Even the owner's manual will tell you not to tow in OD. That is the #1 easiest way to nuke a 700R-4...

Tow in drive. Slow down when you're towing, remember that trailer has all the aerodynamics of a barn and moving that air 1 mph faster requires exponentially more power. 55-60 mph, let the rest of the world pass you.

Better gearing helps a ton. 4.56's will be wonderful when you're not towing...should give you a ton of snap and response you never had before. Plus it'll keep you at a better speed when towing.

Fordum, I am old school, I use a calculator to figure rpm's for various gears and tires.

speed (mph) x diff gears x OD (if applicable) x 336 (for lock up auto or manual tranny, 355 for non lock up auto) / true tire diameter.

The cool part is plenty of variations can be dropped into te mix, and I don't need to be online to do it. :D

Rene
Click to expand...
 
700r4's die easy enough they way it is, we dont need to do anything to accelerate it at all lol. I think Ive killed 5 or 6, cant really remember.
 
Whats really scary is Im planning on resurecting the truck I killed all those transmissions in. looks like a LS tpye engine and a 4L60E or preferably 4L80E for me, no more of this replacing a trans once a year BS.
 
Fordum, I am old school, I use a calculator to figure rpm's for various gears and tires.

speed (mph) x diff gears x OD (if applicable) x 336 (for lock up auto or manual tranny, 355 for non lock up auto) / true tire diameter.
Click to expand...

Yep, I used to have that programmed into my TI-59 calculator. Haven't seen the formula in years. Thanks for posting it.

Given my business, I am usually within an arms length of an online computer most of the time, so I have gotten lazy.

Its fairly simple to derive, and I have had to do it from time to time. But its nice to have it written down.
 
BTW, if you want to talk gear ratio, my old Jeep had 5.somethings in it I think. With the top off, the windshield down, and me crouching down behind the dash. It would almost do 60 with the 134ci 90hp Hurricane screaming under the hood.

In all the years I had it, I never had the nerve to put a Tach on it..........
 
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