Attention: TDR Forum Junkies 
I installed my PacBrake PRXB this last weekend and here are my notes:
This was installed on a 2005 3500 4X4 G56 that is totally mechanically stock. I consider myself to be an average "backyard mechanic" so this is from the viewpoint of an amateur, not a professional installer. If you're going to do this project yourself, and have average mechanical skills, I would say it is about a 7 out of 10 for difficulty. This would get easier, with more installs, but the first one is always more complicated.
1. This project is a lot easier if you have access to a shop and lift. This could be done in your driveway, but it's a lot easier to get it off the ground to work on.
2. Taking the right front wheel of, and the plastic wheel liner, will let you have full access to the turbo outlet exhaust elbow. I did not take the driver's side liner out. Getting the stock elbow out, and the new one in, will take a little patience. I had to loosen the first exhaust support bracket and have a helper pry back on the exhaust pipes in order to get enough space to get the stock exhaust elbow out of the exhaust pipe and away from the turbo. The clamps that hold the elbow on are very stiff and will take a little prying to get them to release. It's a tight fit to get the PacBrake back in, re clamped, and aligned with the exhaust (photo 1).
3. I found it easier to weld the small air tank to a cross member, behind the driver's front wheel. By doing it this way I didn't have to drill the frame (photo 2).
4. Installing the compressor is pretty straight forward, but it's tight working around the oil dipstick, and getting the standoff spaces under the pump (photo 3).
5. Wiring: Although there are installation instructions, with pictures and a wiring diagram, you will have to sit down and study the wiring harness to get it all figured out. There was an error on my instructions which said to "connect the red wire, with a white stripe to an ignition source. " On my kit, both wiring harness power leads were red and neither had a red strip. The one they want you to connect has a "push-on" connector, while the other power lead, that goes to the battery, has a terminal connector on it to put on the battery post clamp. Also, the one that goes to the ignition source has a 10amp fuse, while the battery power lead has a 30amp fuse. Connecting the two leads to the ECM is pretty straight forward. I think this could be done from underneath, but I did it by standing on a stool over the grill and reaching down to the ECM control unit. I tried to do this without removing the ECM plug, but I couldn't get the little red plugs out of the main ECM connector so I disconnected the batteries and took the plug off and used a very small metal rod to push the plugs out. Insert the leads into the plug until they seat and don't move back out when you tug on them.
6. I installed the master on/off switch on the dash, just about where the enclosed picture put it, but I had to put it further up on the plastic trim piece, as there was no room behind the trim piece where the instructions had shown it, to get the switch positioned vertically straight up and down.
Here are my initial impressions. The brake works as advertised, but if you don't use the optional clutch switch, it will start to engage the brake while you are shifting. Doesn't really feel like it is slowing the truck down, but you can hear the butterfly valve closing and opening. If you shift very slow, it will slow the truck down. I don't know if this is un-necessary wear and tear on the brake, but it can be prevented by just keeping your foot on the gas peddle just a little, which prevents the brake from engaging. I drove 250 miles home and tried it out in different situations, including engaging it with the cruse control on, and it seemed to hold speed while going down 6% grades. I'll know more after I hitch up the 5th wheel and try it on hills.
In summary... It took me (with a helper) 5-6 hours to install the brake. Getting the old exhaust elbow out, and the new one in, will take some effort and patience. The wiring instructions could be better. All in all, a good weekend project... .
This was installed on a 2005 3500 4X4 G56 that is totally mechanically stock. I consider myself to be an average "backyard mechanic" so this is from the viewpoint of an amateur, not a professional installer. If you're going to do this project yourself, and have average mechanical skills, I would say it is about a 7 out of 10 for difficulty. This would get easier, with more installs, but the first one is always more complicated.
1. This project is a lot easier if you have access to a shop and lift. This could be done in your driveway, but it's a lot easier to get it off the ground to work on.
2. Taking the right front wheel of, and the plastic wheel liner, will let you have full access to the turbo outlet exhaust elbow. I did not take the driver's side liner out. Getting the stock elbow out, and the new one in, will take a little patience. I had to loosen the first exhaust support bracket and have a helper pry back on the exhaust pipes in order to get enough space to get the stock exhaust elbow out of the exhaust pipe and away from the turbo. The clamps that hold the elbow on are very stiff and will take a little prying to get them to release. It's a tight fit to get the PacBrake back in, re clamped, and aligned with the exhaust (photo 1).
3. I found it easier to weld the small air tank to a cross member, behind the driver's front wheel. By doing it this way I didn't have to drill the frame (photo 2).
4. Installing the compressor is pretty straight forward, but it's tight working around the oil dipstick, and getting the standoff spaces under the pump (photo 3).
5. Wiring: Although there are installation instructions, with pictures and a wiring diagram, you will have to sit down and study the wiring harness to get it all figured out. There was an error on my instructions which said to "connect the red wire, with a white stripe to an ignition source. " On my kit, both wiring harness power leads were red and neither had a red strip. The one they want you to connect has a "push-on" connector, while the other power lead, that goes to the battery, has a terminal connector on it to put on the battery post clamp. Also, the one that goes to the ignition source has a 10amp fuse, while the battery power lead has a 30amp fuse. Connecting the two leads to the ECM is pretty straight forward. I think this could be done from underneath, but I did it by standing on a stool over the grill and reaching down to the ECM control unit. I tried to do this without removing the ECM plug, but I couldn't get the little red plugs out of the main ECM connector so I disconnected the batteries and took the plug off and used a very small metal rod to push the plugs out. Insert the leads into the plug until they seat and don't move back out when you tug on them.
6. I installed the master on/off switch on the dash, just about where the enclosed picture put it, but I had to put it further up on the plastic trim piece, as there was no room behind the trim piece where the instructions had shown it, to get the switch positioned vertically straight up and down.
Here are my initial impressions. The brake works as advertised, but if you don't use the optional clutch switch, it will start to engage the brake while you are shifting. Doesn't really feel like it is slowing the truck down, but you can hear the butterfly valve closing and opening. If you shift very slow, it will slow the truck down. I don't know if this is un-necessary wear and tear on the brake, but it can be prevented by just keeping your foot on the gas peddle just a little, which prevents the brake from engaging. I drove 250 miles home and tried it out in different situations, including engaging it with the cruse control on, and it seemed to hold speed while going down 6% grades. I'll know more after I hitch up the 5th wheel and try it on hills.
In summary... It took me (with a helper) 5-6 hours to install the brake. Getting the old exhaust elbow out, and the new one in, will take some effort and patience. The wiring instructions could be better. All in all, a good weekend project... .
