6.7L Cummins Forum

Yesterday, while coming home from a camping trip, I turned into a side road around 15 mph. The truck and 5er started to buck. I know it's the exhaust brake engaging and disengaging. I turned the exhaust brake off and it went away. Appears it was at a point in speed where it need to disengage. Turned off...speed picked up slightly...turnes back on etc.etc. etc.. Anyone had this problem?? Any flashes out there??

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7.5 3500QC 6.7CTD 68RFE Build date June 2007
Superchips tuner 3808, Boost/EGT Laser Gauge, Airaid cold intake

Mine does this occasionally usually only one chug when coming out of a corner or if I have lifted slightly off the throttle when going through an intersection or in a line of traffic. It seems like the computer can't decide whether to shift up a gear or apply the engine brake. Like I said, it's only occasionally, so I'm not worried. Other than that the truck has performed flawlessly. It has almost 35,000 kms on it with close to 20,000 pulling our travel trailer. The big test was going down the Coquihalla into Hope last summer, the engine brake held truck and trailer to under 60 KMs when necessary. Other guys were going by us in the left lane with smoking brakes.
Must be nice that you can still camp! Our trailer has been parked with antifreeze in the water lines for 4 weeks now.

Yes, I have had this before and only at slower speeds...Like you said, the exhaust brake works great. I usually camp until end of December and start back up in February. We have a mild climate here...Thanks for your input

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7.5 3500QC 6.7CTD 68RFE Build date June 2007
Superchips tuner 3808, Boost/EGT Laser Gauge, Airaid cold intake

I've also had it happen a couple of times both empty and hauling my tractor and I just down shift to get out of it. We've already had snow here up North you lucky bass turd!

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2007.5 Dodge Ram 3500 HD,QC, 6.7L Cummins, 6speed Auto, 4X4, Bighorn Edition.
Click for installs: Carr Steps PML Diff Cover Edge Juice with Attitude Volant Intake Hankook ATM RF10

Same here, I've had that 'Bucking" thing happen, but usually only once then it goes away. We will be taking our 5'er out this weekend and possibly 2 more times before the end of the year. 1 time in January and begin every other week from then. It's still high 50's low 60's here in Sunny New Mexico.

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07.5 3500 Quad, SRW, 4X4, Laramie, Leathered, Dark Metallic Gray, 6.7, 68RFE, 20K Reese, Ride Rite's, 2 Viair air compressors, Bully steps, Kleinn Locomotive air horns (5 in all), Billet polished locking fuel door, 'A' pillar mount Auto Meter Pryo, PML X-deep trans pan
06 Durango 285 RL 5'er Lifted by KZ

After doing a little research and calling my local friendly Service tech to verify my info here's what I know.

The exhaust brake is dependent on engine speed not truck speed and is controlled by the ECM. The Exhaust Brake should shut down at 1100 RPMs so when towing keep an eye on the Tach and manually upshift/downshift depending on your needs.........also don't forget the tow/haul switch.

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2007.5 Dodge Ram 3500 HD,QC, 6.7L Cummins, 6speed Auto, 4X4, Bighorn Edition.
Click for installs: Carr Steps PML Diff Cover Edge Juice with Attitude Volant Intake Hankook ATM RF10

So, hovering around 1100 that causes the bucking problem...A simple down shift or up shift show stop the problem...or just don't let it get to 1100. Got it
I never use tow/haul. Far too aggressive for me.

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7.5 3500QC 6.7CTD 68RFE Build date June 2007
Superchips tuner 3808, Boost/EGT Laser Gauge, Airaid cold intake

For us owners with a programmer I agree.

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2007.5 Dodge Ram 3500 HD,QC, 6.7L Cummins, 6speed Auto, 4X4, Bighorn Edition.
Click for installs: Carr Steps PML Diff Cover Edge Juice with Attitude Volant Intake Hankook ATM RF10

Had a couple of the TSB's done last week, I'll try to dig up the numbers. Harsh 3-2 down shift, reflash for fix, seems to be gone now. Electronic throttle light on, It happened 2 times, reflash, no problem yet far. Enabled high idle function. Man this is a neat feature, a real must do when you go back to the dealer.

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07.5 3500 Quad, SRW, 4X4, Laramie, Leathered, Dark Metallic Gray, 6.7, 68RFE, 20K Reese, Ride Rite's, 2 Viair air compressors, Bully steps, Kleinn Locomotive air horns (5 in all), Billet polished locking fuel door, 'A' pillar mount Auto Meter Pryo, PML X-deep trans pan
06 Durango 285 RL 5'er Lifted by KZ