2" Rear Drop

psychoticide · October 29, 2002

This one is to all of you who have done any kind of lowering to your truck. When the 2" lowering shackles are used to lower the rear of the truck, do you have to use the 2" lowering springs as well?? Or are the shackles all I need? How difficult will it be to lower the rear of the truck?

belmontrider · October 29, 2002

i put 2" drop shackles on my 2000 z71. you don't need to do anything else, the shackles will work with all the stock parts. my shackles have a 1" or 2" drop and the zerk fitting, i did the 2" when i first put them on but i tow alot and changed them to 1". i have my torsion bars cranked pretty good so it sits level with no load. they're easy to put on but you gotta drop the hitch to get some bolts out.

psychoticide · October 29, 2002

So no wheel alignment is needed....just bolt on the shackles and go, right?

belmontrider · October 29, 2002

you got it

siskiyou · October 30, 2002

Why would you want to change your shackles to lower it 2"? I added an extra leaf spring to the rear of mine which then raised the truck 2" in the back. To bring it back down I just removed the factory 2" lift blocks and it brought it right back to the original height. I did have to replace the u-bolts as the were then too long.

TROYROBO · October 30, 2002

i bought 3 inch lowering shackles for mine a did it myself in about 1 hour--pain to lower the hitch to install them but i really like how it sits now troyrobo

psychoticide · October 30, 2002

Thanks to all for the great info! :thumb:

taki1 · October 30, 2002

question for siskiyou - if you remove the factory 2" lift blocks, do you mess with the driveshaft angles?

goldnrod24 · October 30, 2002

To bring it back down I just removed the factory 2" lift blocks and it brought it right back to the original height. I did have to replace the u-bolts as the were then too long.

I got the idea that the original poster had a 2wd. If so, then he doesn't have the 2" blocks, they are a 4wd item.

Randy, who also removed the 2" blocks from my C3.

taki1 · October 30, 2002

so the 2" blocks can be removed without any adverse effects on the drivetrain on a 4wd vehicle?

ive heard of driveline vibration (because the driveshaft to differential angle is different) when these blocks are removed...

is there any truth to this?

psychoticide · October 30, 2002

Yes, my truck is 2WD.

siskiyou · November 2, 2002

To answer taki1's question, yes you do change the driveshaft angle by removing the lift blocks. You also change the angle by using the lowering shackles because either one of them moves the rear axle closer to the frame. In my case when we added the extra leaf in the rear springs it raised the truck up 2" so by removing the lift blocks all it did was return it to its original height. When I first had the springs installed we removed the 2" lift blocks and installed 1" lift blocks and it was still too high so after driving about 4000 miles with 1000 miles towing I removed the 1" lift blocks. I have never felt any vibration or other adverse affects due to the hieght.

goldnrod24 · November 2, 2002

so the 2" blocks can be removed without any adverse effects on the drivetrain on a 4wd vehicle?

ive heard of driveline vibration (because the driveshaft to differential angle is different) when these blocks are removed...

is there any truth to this?

I've encounted no vibration since removing mine ('01 C3). I'm not sure, but doesn't the trans sit in the same location/plane regardless of 2wd or 4wd? If so, then the changed angle theory doesn't work. <shrug>

Randy

visit an online C3 owners group at:

http://groups.msn.com/gmcc3owners/

siskiyou · November 2, 2002

That is a good point that I had not thought of. I am going to have to go out and look at my truck when my wife brings it home and see if the transfer case offsets the driveshaft from where it would be on a 2WD. I did notice that the driveshaft sits straight (not level) with no tilt at the u-joints.