PRXB exhaust brake on a 2004.5 48RE

[cerberusiam]

The manual valve allows the TC to charge in park instead of having to put it in neutral. Installed and positioned correctly in a VB that is not worn if works fine. In a worn VB or misadjusted a couple thousandths and it eats the forward clutch pack while in park. Talk to your builders about installing and positioning it correctly, some will put them in but others won't for the potential liability.

 

[Superdawg]

Slowly starting this project. I wanted to put the air compressor on top of the fuse box in the engine. Less heat and vibration than when mounted to the engine but still some heat for freezing temperature operation. This set up will allow me to set it on top and with enough length in the air and electrical lines, I will be able to lift it off the fuse box for access. I plan on putting a bungee on top but it probably won't need it.
The large hole in the center is for the screw handle on the top of the fuse box. The rim fits snugly around the top of the fuse box cover. No sliding around.

 

[Superdawg]

Got the truck back from the trans shop. Just to reiterate, truck has 155k, but 20k on the rebuilt 48RE. I bought the parts and had them install:
Trans go shift kit
Billet front servo/accumulator
Heavy duty strut
Keep existing 5.0 lever
Billet band anchor
Slip in band

Shifting into park was a little difficult and they replaced the "rooster comb". Shifts into park better now.

After a few days of driving, I like it. Mushy shifts gone. Not too bad though, I think drinking coffee during a shift is still okay. Much firmer. Downshifting seems to have more braking effect but that could be my imagination. I wish I would have done this a long time ago. Seems like more fun to drive. My wife, who has been Lexusized, would probably prefer a mushy, Cadillac shift.
I am going to try to install the exhaust brake this weekend.
On that note, since I live in So Cal w/ a higher population density, has anyone thought about adding a small flashing led brake light(warning)to go on when the exhaust brake is activated, but prior to brake lights going on? I was thinking about the possibility of someone running into the back end of my truck when it slows down but no brake light comes on. Lots of traffic here.

 

[p-Bar]

Good luck with the Exhaust brake install .I think I spent more time on installing the electrics and wiring than I did on the mechanical side.

 

[Ozymandias]

Dont need a light, brake power isn't high enough for this, would just confusing other drivers.

 

[Motorhead]

The brake itself can be installed from under the hood but removing the right front wheel and plastic wheel well cover makes it a lot easier.
As to activating the brake lights too, I have often thought of that with my 6 speed and the Pacbrake. What I thought about doing was to take the 12 volt POSITIVE signal that goes to the Pacbrake air solenoid and run it to one of the Bosch style cube relays. These are the brand I have used and they are high quality: http://www.qualitymobilevideo.com/bu5084.html
Take the "85" terminal of the relay and ground it. Take the 12 volt positive SIGNAL wire from the pacbrake solenoid and connect it to the "86" terminal of the relay. Now when the pacbrake solenoid is activated, the relay will close. Run a FUSED 12 volt battery lead to the "30" terminal of the relay. Take a wire from the "87" terminal, NOT the "87A" and run it to the BRAKE LIGHT SIDE of the brake light switch located at the brake pedal and connect it.

 

[Motorhead]

Dont need a light, brake power isn't high enough for this, would just confusing other drivers.

The PRXB has more holding power than your Jake brake.

 

[Superdawg]

I completed the install. Two days of on/off working on it. After 50, I don't enjoy being a contortionist under the truck as much.
No leaks that I can tell. I may be regretting the suggested switch location (dash, left of steering wheel) because the steering wheel/turn signal blocks my view of the lighted toggle switch.
Operation: Only drove in town, OD locked out,
In drive: EB slows it down pretty well and switches off at about 35 mph. Not really enough to want to add the brake light for EB operation.
In L2: Whooee! Considerable braking power down to about 15 mph (18mph according to Pacbrake IIRC). Definitely want a brake light on for that.
I can barely feel the vibration from the compressor being on in its location on the fusebox in the engine. Sure can't hear it over the diesel. The combo of the shift kit and EB sure changes the operation of the truck. I can't wait to tow the fiver down a long grade.

I like where I installed the compressor. The EB wiring harness is pretty large and is routed right next to the battery. The photos show the compressor in place and lifted up and off to the side. The air hoses and wiring are all routed from the compressor toward the cab to be able to instantly lift the compressor and move it to the side to access the fuse box. With the engine closed, the insulating blanket under the hood just barely touches the top of the solenoid, the highest part of the compressor. Even with a good bump, that compressor is not going anywhere with the hood closed.

This kept the engine less cluttered up to make removal and replacement of fuel rail parts easier.

Motorhead: Good info on the relays. I will file that away and maybe use it in the future. Thanks for explaining it so even I could understand.

 

[Motorhead]

Looks nice! I liked your "After 50, I don't enjoy being a contortionist under the truck as much." I'm looking at 64 this summer and while I still do it, "IT" doesn't get any easier!
With the PRXB installed on my 2007, 5.9, G56, Coming WEST on I-80 through the Donner pass towing our loaded 28ft TT and 4 adults and a dog in the truck, I never had to touch the service brake coming down into Sacramento. This was using the PRXB in 5th and 6th gear.

 

[Ozymandias]

I installed the air compression in the fender over the plastic wheelwell, there is PLENTY of Room for them, left or right side, all empty space.
Dry and clean. Not even dust up there.

 

[p-Bar]

I installed the air compression in the fender over the plastic wheelwell, there is PLENTY of Room for them, left or right side, all empty space.
Dry and clean. Not even dust up there.

I did the BD brake as I liked the bronze bushings they used and mounting the compressor in the wheel well like Ozy's

 

[Superdawg]

Update:
In drive w/ overdrive on: EB is off at 35 mph
In drive w/ overdrive locked out (tow/haul) EB is off at 25 mph
In L2, EB is off at 15 mph
In L1, EB is off at 5 mph.
Wow.

RE the shift kit, sometimes I get a little bit hard of a shift at what I think is a 3 to 4 shift. Possibly a locked to locked shift from 3-4?

 

[p-Bar]

RE the shift kit, sometimes I get a little bit hard of a shift at what I think is a 3 to 4 shift. Possibly a locked to locked shift from 3-4?

I find that also I have learned to back off on the pedal for that shift. It's the extra line pressure causing that hard shift.

 

[Motorhead]

Update:
In drive w/ overdrive on: EB is off at 35 mph
In drive w/ overdrive locked out (tow/haul) EB is off at 25 mph
In L2, EB is off at 15 mph
In L1, EB is off at 5 mph.
Wow.

RE the shift kit, sometimes I get a little bit hard of a shift at what I think is a 3 to 4 shift. Possibly a locked to locked shift from 3-4?

My $0.02 worth... Even though my truck is the G56, 6 speed, I try to avoid ever using the exhaust brake except in 5th or 6th. I mainly use it in 5th or in my case, DIRECT 1:1. Your 3rd gear is direct or 1:1. The lower gears, with exhaust brake aren't designed for the HIGH deceleration load with the exhaust brake applied...especially the braking force that the PRXB gives. BUT, if I need to use it in an emergency then It is applied no matter what gear I am in. AGAIN....Just my $0.02 worth.

 

[p-Bar]

I'll drop it into 2nd gear at about 45 mph . I have 14k to stop it does fine. You will need to experiment around

 

[p-Bar]

You know one thing I was thinking about . I followed the old Jacobs brake thread when they were testing them on the Dodge. They said they couldn't determine when the thrust bearings were being installed on the 48 re so that was one reason along with not enough ram in the computer to qualify it for the 04.5 . What is your build date ? I see you are 555 motor so you are pre 04.5?

 

[Superdawg]

Mine is a 04.5 325/600 with a build date of 4/04. As far as the thrust bearing goes, this transmission was rebuilt (regular rebuilt, not performance parts) about two years ago. The thrust bearing was part of the rebuilt kit.
Motorhead: Good to know about the lower gears.
Thanks all!

 

[Superdawg]

I have another question reference the install of the wiring harness. I spliced in one wire on the computer bolted to the side of the engine. Between the ECU and the stock fuel filter housing, the stock engine has a 3 wire connector that was capped. The Pacbrake harness plugs into that. What is that three wire connector?

 

[Superdawg]

I did get a check engine light, code P 1740. After a search, it seems common with the higher pressures in the trans due to a shift kit/upgraded valve body/ or upgraded torque converter. I cleared it and won't worry about it too much.

 

[Ozymandias]

I've never seen such a code the last 40000M with mine.