Upgrading from 1/2 ton to 3/4 ton leaf springs
- Thread starter Logan R
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I would have the 3.08 I’m guessing I do have the 5.7 and it’s only got 133,000 on it if that makes a difference. I am willing to replace other parts as I know that heavier leaf springs mean probly upgrading other parts as well
You have a really light duty truck. IMO all the work needed to tow 6-8000 lbs. isn’t worth it. Just find a 2500 that’s done. If “I” needed to haul that, I’d sell my K1500 with 3.42 and only 86k on it.
1990Z71Swede
I'm Awesome
Sell it & buy a K2500. Apart from 4WD to get you unstuck it has the suspension to take the load, 3.73 gears, a rear axle that can't be broken, a better gov"bomb", HD exhaust valves, and... last but absolutely positively not least, a 4L80 transmission.
Still, by far the simplest and most bang for the buck mod you could do to your current ride.
Still, by far the simplest and most bang for the buck mod you could do to your current ride.
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I don't know if this maybe varies by model year. But it's a good indication of the capacity of the truck. Point is, check your owner's manual, and/or your door sticker for the rated towing capacity, maximum GVWR, etc.
Stop guessing. Find out for sure. Your first stop should be the SPID sticker in the glovebox.
3.08 = GU4
3.42 = GU6
3.73 = GT4
Locking differential = G80
But of course that "could" have been changed to a different ratio or different axle in the decades since the truck was built.
What is your brake option code? Depending on the year, you might have the extra-crappy JN3 brakes--weak in front, weak in back, weak master and booster.
Kinda expecting "5", that is, JN/JB/JD5. Decent master 'n' booster, decent up front. Crappy in back. Possible, but not likely to be "6", JN6, JB6, etc. The "6" brakes are far better than the "5", due to the size and design of the rear drum brakes.
IF (big IF) your truck is rated to pull whatever load you're contemplating, you wouldn't need heavier springs. You might "want" heavier springs if you were pulling that load frequently. If the load you want to tow is beyond what's listed in the owner's manual or printed on the door sticker, you're pretty-much screwed if you get pulled over and have to prove to the Judge that you're legal--'cause you won't be.
If that's an acceptable risk, the first thing I'd do is put a heavier AXLE under those same SPRINGS. Get a "light duty" C2500 axle, (NOT a K2500 axle, the width is different) which would have a 9.5" ring gear and probably better brakes than the 254mm (10-inch) leading/trailing shoe rear drums common to the 8.5" ring gear axle assembly. Also get (at least) two wheels since the bigger axle shafts will have six lugs instead of five. You could keep your wheels if you add aftermarket 5-lug axle shafts to the 9.5" axle.
Yeah those JB3 brakes are sketchy enough for stopping the truck alone, never mind towing 5-8k trailer. Then you probably don’t have a transmission cooler to go with (assuming 4L60)transmission, that seem to grenade even without added towing stresses! With enough money and time you could replace brakes, suspension, transmission and rear end though.
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