At a loss, Acceleration Shake
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Agreed! Those are just chunks of rubber, or maybe polyurethane. Either way, not a standard shackle at all! You should have a steel shackle with rubber or polyurethane bushings. Those would eventually rip off I would think anyway and will make the rear loose as hell!
1995 Z71 standard cab stepside
Swapping to 1996 Vortec OBD II
When I had trouble out of my crew cab vibrating, I took the driveshaft out of the rear and drove it in 4wd. You can just remove the rear section, but I took the whole thing out. I took a thick rubber glove and clamped it over the transfer case output to keep it from throwing so much fluid out. This took my vibration away, and later I removed the center support bearing cross member, and put in a solid aluminum driveshaft. I have fixed 2 crew cab short beds this way, and they have been smooth ever since. I tried several driveshaft, had several built, changed angles, new center support bearings, shimmed the center support bearing up/down, nothing worked except getting rid of the 2 piece driveshaft. I spent over 1200 dollars on having the 2 parts retubed, balanced, and repeated a few times. I even put a K2500 factory driveshaft in my K1500, nothing worked except replacing it with a 1 piece. There is a TSB about doing this, I can't remember what it is off the top of my head though.
CBenZ71
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You think I'm good to just put the standard shackle back on? I'm assuming the put this on when it was lifted in 1999. I thought that looked weird. It looks a little longer than a standard shackle, but it should be okay to just go stock?
CBenZ71
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Okay I have been thinking that might be the route I need to go as well. I'll have to find that thread. I was just hoping there was some other more obvious reason for my shake. Lol. Do you remember the cost of the swap?
Yea, start with an OEM shackle from rockauto or something and go from there. Like I said before, I bet your shake will go away when you replace those.
I bought a used driveshaft out of a 2011 crew cab 2wd, my build thread tells most of the details. But to make a long story short, you take the yoke off of your driveshaft. Push it into your transfer case output until it bottoms out, and pull it back 3/4 - 1 inch. Then measure from the center of the u joint hole on it to where the center of the u-joint is on the rear end. That is the measurement the driveshaft shop will need, they will ask for it by "center to center" measurement. Mine was about 78.5 inches, yours should be an inch or so shorter. I bought the driveshaft used, took my yoke in with it, told them the center to center I needed, and brought in the rear U joint so they knew what I needed on the rear end. They charged me about 450 bucks to cut and balance it. My thread is here, start looking on this page or the previous one and read about what I did in more detail.
https://www.gmt400.com/threads/deadbeats-1997-centurion-conversion.27953/page-31
CBenZ71
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For anyone interested, here is what those shackles were. From what I've found they are a drop shackle made by Velvet-ride. Why would the original owner put drop shackles on a lifted vehicle? I have no idea. The idea behind these are that middle rubber piece acts as a shock on top of the leaf spring. Typically the rubber is good for 3 years, this have been on there since 1999. Lol
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CBenZ71
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@RichLo @deadbeat @clgodwin79 @Frank Enstein @Hipster
Okay, need some new opinions if you all have time. Changed out those old weird 2 piece shackles and went ahead and change all the leaf spring bushings while I was at it, it did not do anything for the shake. I put the rear on some jack stands and got this video. It does not do the shake in the air, but it jumps around like crazy when applying brakes(I was braking extremely softly). It also would randomly jolts while the rear tires were spinning in the air(you can hear it on the video). Is this weird? Normal? It seems like the shake is worse when taking off from a stop going up hill. Is there anywhere for me to upload the video some you can see it?
EDIT: I uploaded it to YouTube.
Okay, need some new opinions if you all have time. Changed out those old weird 2 piece shackles and went ahead and change all the leaf spring bushings while I was at it, it did not do anything for the shake. I put the rear on some jack stands and got this video. It does not do the shake in the air, but it jumps around like crazy when applying brakes(I was braking extremely softly). It also would randomly jolts while the rear tires were spinning in the air(you can hear it on the video). Is this weird? Normal? It seems like the shake is worse when taking off from a stop going up hill. Is there anywhere for me to upload the video some you can see it?
EDIT: I uploaded it to YouTube.
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Hipster
I'm Awesome
I think you chasing your tail until you find out if you have a tire/wheel/runout problem. Warped rotor, drum, bent wheel, flat spot, etc.
belt separation/flat spots don't always show up visibly, but it will on a road force balance job. A balance job would eliminate a bunch of variables in this situation(bent wheel/tires problems)and a dial gauge could eliminate warped rotors/drums by checking runout.
You say "shake" but would like a better definition. Out of balance tires bent rims etc ,a shake will almost feel like a wobble that clears up at certain speeds. Driveshaft issues feel more like a harmonics problem that will resurface at different levels at different speeds. A shake is not a vibration so think about what you're trying to describe.
Sometimes the money is better spent on checking for a problem then $$ replacing parts that might not be the problem. Eliminate the simple shyt first.
belt separation/flat spots don't always show up visibly, but it will on a road force balance job. A balance job would eliminate a bunch of variables in this situation(bent wheel/tires problems)and a dial gauge could eliminate warped rotors/drums by checking runout.
You say "shake" but would like a better definition. Out of balance tires bent rims etc ,a shake will almost feel like a wobble that clears up at certain speeds. Driveshaft issues feel more like a harmonics problem that will resurface at different levels at different speeds. A shake is not a vibration so think about what you're trying to describe.
Sometimes the money is better spent on checking for a problem then $$ replacing parts that might not be the problem. Eliminate the simple shyt first.
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