Lowering your 454SS
10/22/1999Rick Metcalf AKA Tweek
So, you lowered your truck 2 and 4 using spindles and shackles and you STILL see daylight through the rear wheelwells. Damn. Now what?
Yep, itís time for another garage thrash. Hereís how. As you know, if you used the shackles to lower the rear of your 454SS, you cannot use the flip kit to go to a 6 inch drop without reinstalling the original shackles and front mounts. I, of course, threw out the original shackles and mounts when I finished the 2/4 lowering, thinking at the time, I would never need them again. Stupid.
Placing the new, cooldaddy jack and 2 ton jackstands under the back of the truck, itís time to see what can be done to rescue this sorry situation. Usual precautions required. The 454SS is really HEAVY. Do not expect the $19.95 per pair jack stands to hold the truck off your body. Also, do not expect the Chinese $29.95 jack to do this job either. Jack the truck, shake the truck, and make sure you are safe to work.
Put your old cheesy jack under the diff. And relieve the load from the springs. Loosen the u-bolts gradually on both sides of the diff. Remove the u-bolts and lower the diff. slightly.
Clamp the leaf spring together with a c-clamp at the center and remove the single bolt there. Take out the overload leaf. Put an abrasive cut-off blade in your circular saw. Really. If you can help it, donít use a saw with a plastic blade guard. The sparks from the blade will melt the guard and damage your saw. You are warned!
Cut the ends off the overload leaf, leaving about .5 inch on each end beyond where the u-bolts hit. This takes a while, throwing sparks everywhere. The sparks will wreck window glass, so be careful. Allow cheap saws to cool from time to time.
When finished, squirt some black paint on the raw ends to keep rust down. Now, put the stub of the overload leaf on TOP of the leaf spring instead of below, and re-install the center bolt. Jack the diff. back up to the leafs, and re-install the u-bolts, torqueing them to at least 85 ft. lbs. Torque evenly in steps so you donít pull the u-bolts off center or twist the u-bolts during tightening.
Yep, an almost free mod. You just lowered the rear of your truck about .75 inch, the thickness of the overload leaf. You will lose some load capacity, so keep this in mind when loading up the firewood this winter. In my truck, even with a load, I never hit the overloads, so it was no loss to me to remove them. But, keep this in mind when thinking about cutting the overloads down. Itís kind of hard to put the ends back on the springs.
While you are there, open the diff. cover and change the lube. The "fly-weight" Dana diff. is complex and should be changed regularly. Use a good quality lube as recommended in the owners manual, and DO NOT add the GM posi additive. Chevrolet service info. Specifically advises NO ADDITIVE in the Dana diff. If your posi action is slow or non-existant, change the lube and skip the additive.
What the heck, you were already dirty and greasy anyway!
When assessing the posi, remember that it senses a 10 RPM speed split between the axles to extend the flyweights and engage the posi clutches. Basically, at low speeds with no RPM split, the unit acts as an open diff. Say it with me now, fuel efficient. So, when manually turning one wheel, you donít get the normal posi reaction of both wheels turning the same way. Donít think itís broken when itís not. Often, on a hard launch, the speed differential rises too quickly, and the fly-weights canít extend quickly
More rear end stuff
enough, results in you leaving ONE dense, smoky tire track, and feeling rather foolish. Light brake-torquing solves this problem.
Author nor the 454SS Site/webpage is NOT responsible for any errors in this text. Also, not responsible for damage to you, your truck or to your tires. using this modification is decided by you and you accept all responsibility's of install and or any damages to anything it may cause. Check with your state and local authorities for legalities as to this modification.