reddwar
Valley Center Ks. /Now Scotland SD.
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First I would tell anyone looking at a exhaust brake to get a Pac brake as it does not lose brakeing power as you lose RPM. That said my jake brake retired at just under 100,000 miles on the way to AZ. Stopped at a Dodge dealer & he wanted $800 + $300 to replace it. Went to cummins cost $269. If I had my tools I would have replaced it but a local shop said $50 they would replace it. Well it works but only if under 40/45 mph if over it does not work?
Why? Why does my Jake brake not work if over 40/45?
red
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coolbreeze01
Redding, Ca
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Joined: 08/24/2006
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Does the failure to activate coincide with RPM at all, or just speed?
2008 Dodge 3500 With a Really Strong Tractor Motor...........
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glamisorbust
Arizona
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Something's wrong. I drove truck for years, and as long as your throttle was completely closed, the jake brake should be in full effect, all the way down to about 600rpm's.
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JIMNLIN
out here
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Joined: 09/14/2003
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Somethings wrong in the programming or your not using enough RPMs.
Remember the exhaust brake max braking performance comes at max rpms. So if your rpms are low at 40-45 mph so will the exhaust braking power.
Actually the Pacbrake looses braking power according to RPM just like all exhaust brakes. Now the Pacbrake does have a bit more braking in the lower 1800-1900 rpm than the Jacobs or other brands or so they advertise.
My Jacobs works down to zero speeds in any gear including reverse if needed, however its a NV5600 manual tranny.
"good judgment comes from experience, and a lot of that comes from bad judgment" ............ Will Rogers
'03 2500 QC Dodge/Cummins HO 3.73 6 speed manual Jacobs Westach
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jims1
NC
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The PacBrake uses an independant compressor to activate the butterfly valve.
The Jake uses a vacuum pump thats driven by the main belt on the front of the engine. As the engine rpm slows, the amount of vacuum decreases.
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reddwar
Valley Center Ks. /Now Scotland SD.
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A little more info: The jake brake does not come on in 4th gear, but comes on when it down shifts down to 3rd between 40 & 45. If I lock it in 3rd no jake brake above 50, I do not fell it come on but can feel it when I push in or turn jake off at around 50. In 2nd no jake above 30 & do not feel it come on but when I disengage can feel it come on at around 30.
Now my Jake brake worked for close to 100,000 miles. Have a 07 5.9 auto. Back when it was working, it would stopped working at around 20 mph if you wanted braking below that you had to shift down. As the rpm would go up when you shift down.
Pacbrake the old ones used a vacuum pump like jake & the rest. But then pacbrake got smart & went to a 12V air compressor so when rpm's go down you do not lose braking. Also you have air for your air bags, & if you need to air a tire up. Also no one is going to try to sell you a pump for $800 or replace it for $1,l00 like Dodge did.
red
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Red Birder
Retired and Traveling
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Sounds like the shop that replaced the pump for you screwed something up. If you have installation drawing, carefully review how it is hooked up. Maybe you can spot the mistake and correct it yourself.
2005 Cardinal 29WBLX 5th Wheel
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reddwar
Valley Center Ks. /Now Scotland SD.
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After I had the new pump installed we went to Vegas & on the way we stopped at Laughin. Comming down that big hill into Bullhead city the jake was working. After we left Vegas we were going to go by Mexican Hat as I have been down the San Juan river just wanted to see it from the top side then take I 70 east. But found I had no jake brake so we dropped down to I 40 as it is a easy run.
red
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reddwar
Valley Center Ks. /Now Scotland SD.
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Talked to Jake today could not believe it when he said "never heard that one before" so they were not help. We have two dodge dealers in town one I would not take anything to, the other is ok but. I am going to take it to Cummins next week will let you know what I find out.
red
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#40Fan
Colorado
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Does anyone that claims the vacuum operated exhaust brakes fade at lower RPMs have any proof, other than what their specific exhaust brake manufacturer claim?
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2011 Ram 2500 CC LB CTD G56 3.42 Mineral Gray
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