Mackpro

Mack service bulletin on ride height. give me the last 6 of the vin and I can look it up and see what rear suspension you have and get you a better anwser on ride height. sb136012.pdf

Also found this Email responce from Mack on the issue========= These parts are for CHUs chassis that may be experience a reoccurring resonant vibration in the cab while under load in mid to high-range gears. Typically the vibration is most prevalent at highway speeds (40-60 mph) when the chassis has to negotiate a grade or when full engine power is required. The reoccurring resonant vibration will occur in the cab and in some cases may shake the dash. The cab can be isolated from the engine vibration frequencies by the installing the following parts. See attached document "CHU_VibrationComplaint Resolution".

Found the Email from Mack about the vibration============== I received your voicemail regarding the CHU613_1219 unit with the vibration complaint. Jim Gallagher is correct we have seen this issue before in which there is a reoccurring resonant vibration in the cab while under a load in mid to high range gears (at approx. 40-60mph). Here is a parts list that you will need based on a 300mm frame and “AL” suspension (see below). If you have any questions – let me know. Rear Suspension AL461 – AL401 300mm Frame Part Number Qty Front Cab Mounts 30QS4590M 2 Shelf Bracket L.H - 300 30QS4617M 1 Shelf Bracket R.H - 300 30QS4617M2 1 Upper Frame Tie - 300 30QS4619M 1 Upper frame Tie Bolts 27AM16 4 Upper Frame Tie Nuts 191AM4 4 Rear Engine Mounts 20QL414M 1 Front Drive Axle Seats N/A N/A Rear Drive Axle seats N/A N/A Edge Shocks 4000-60675001 4 Upper Sleeve N/A N/A Upper Sleeve N/A N/A Lower Sleeve N/A N/A Thanks, - Adrian

I'm cleaning out an MP8 EGR cooler today and tommorrow. At least with the ASET its easy to remove and clean. With the MP8 you gotta pull the turbo and a bunch of other crap!

I wouldnt adjust the ride height unless you had the exact ride height measurment availible. There are at least 3 different height settings for the rear air bag height depending on the type of air ride. Its so confusing we have a service bulletin next all the different guages that we have for measuring ride height. On the CXU and CHU you dont shorten or lenghten the rod on the valve, you actually loosen the bracket on the frame that the valve sets on and you rotate it one way or the other to adjust it. Too much up or down and it will cause vibration and even possible tear the syncro out of the transmission. Eaton Fuller likes to deny warranty for syncro damage, they claim they can tell if it was caused by improper ride height. Your new CXU should have come with a Maintance and Lube manual, in it it tells some on the ride height adjustment. I will try and find the service bulletin and post it here. Also the cab air bags have a measurment too, I will see if I can find it. We had 3 or 4 CXU's and CHU's with the vibrations when new and we installed the new motor mounts, cab mounts and rear shocks. The new rear shocks were alot stiffer than the ones that came on the truck. I always wondered if when the shocks started to wear out , would the vibration return. When the CXU and CHU first came out we still had "Mack" engineers in Allentown, I was talking to one about the vibration and he said it actually wasn't the engine vibrateing, it was a sound wave put off by the engine under a certain load, the cab was absorbing the sound wave and causing the felt vibration, kinda like when your in your car at a stop light and the guy next to you has a loud sterio with giant subwoofers cranked up and you can feel it in your car.

Got your text last night but didnt hear the phone. As the other guys said, EGR cooler needs blowing/cleaning out.

4.17 gears were good in older Mack engines and even the new MP engines but the 2004 and up AI ASET in the CV, LE and MR's just didnt like them. RowdyRebel: Last week I was chase'n a low boost problem on a ETECH for almost 2 days. During test drives I could hear what sounded like boost pressure leakin off. Kept pressurizing different parts of the intake system and everything was tight(leakfree). I was fixin to replace the turbo when I climbed on top of the truck and put my hand over the exhaust pipe and could hold back the exhaust pressure with my hand. Pulled the muffler off and found the baffle in the bottom had broke loose and lodged sideways in the middle of the muffler stopping it up. Worth a look.

Thanks for the kind words Kilo6. I wish I would have been able to clean out that EGR cooler but it was plugged solid. Cant wait to see if your fuel milage will improve and get above the 5.7mpg with the other things we did. Gotta get that HP muffler ordered for ya and cant wait to see the results.

When you get the decals on, take some more pics and post them as I want add it to my desktop background. Beautiful truck!

It's nice to "copy and paste" all the nice things said about Mack/Volvo and their new engine's but if you had to work on them every day you would be singing and different tune. As I have said they are a good engine and have the potental to be the best if we can get some better quality parts suppliers and just a few small changes.

We still have 2 Liberty Edition MH's around here. One runs everyday haulin logs. I posted a few pics on here several months ago. Years ago we had a Sturdicraft (furniture products) warehouse here in town and all they would run was Mack cabover V-8's. When it closed the trucks were all sold off and thats where these came from. A couple of there Cruiseliner V-8's were the last to sell and they looked better and newer than the MH's. Our boss has a red, white and blue 1976 Special Edition Cruiseliner locked up in a barn, its all orignal with low miles, dont know what it edition it was called though.

The only way Mack could survive without Volvo now would to use Cummins and /or Detroit engines, Mack or vendor trans and of course Mack or vendor rear axles. If someone could buy Mack from Volvo , ditch the MP engines and be like Peterbuilt and Kenworth. Mack would have an advantage over Pete and KW with having their own transmissions and axles. I feel Freightliner and International are not a threat to Mack, at least in our area. KW and Pete are our biggest competitors around here, they cant even give Volvo dump trucks away around here, dont know why Volvo even bothers building them. With all that said, our MP engines are getting very close to having all the bugs worked out and looks like it will be a great engine soon. Just saw a bulletin from Mack that says the MP8 with SCR can be bumped to 555 HP and over 2000 FT LBS of torque, but only in the Titan. I assume by useing the larger MP10 radiator in the Titan they can do this. We have sold 2 MP8 505HP and they guys love them, says its hard to tell when the trailer is loaded or not. I dont see Volvo selling Mack anytime soon though.

As FJH stated you probably busted a cermaic cam lifter, sadly it happens alot. When ever we have a ASET apart we put the newer style hold down bolts in. I dont remember the pre ASET (2003 and older) engines breaking but anything is possible.

AI engines need to be speced almost perfect to get good perfromance. We have had bad combos like 8LL fuller trans, 4.17 gears and tall 24.5 tires. Finally had to change the rear gears to 4.64 to get it up and going. Tourque curve on an AI is screwy.

I hope he has 4.42 or 4.64 or he's in trouble from the start.

We still see alot of problems with the boost pressure relief valve, the screw on end cap on the newest style/part# seems to screw itself out and cause low boost. We screw in the end cap as far as we can and hammer/ping over the end to keep it from happening again.

Dont feel bad, I waited 3 weeks for some rod bearing for an MP-7 engine. Now have a 2011 GU with a bad dash display and Mack cant say when we will ever get one.

We have lots of CV dump trucks around here. With the AI engine the usual average MPG is 5.2 so your not off by much.

These were plain ETECH engines around 2000-2001. Trying to think if I have seen it on any ASET AC engines. Gearing and tire size is the only the thing I have seen help with power for the AC enines. Bigen (CHN AC ASET) said after we installed a coolant shutoff on his fuel heater for the summer his MPG and power went up?

I have seen improvements in power on certain CX style trucks that had the muffler underneath the cab/sleeper. That style muffler seemed very restrictive. A straiht pipe was put in place of the muffler. The truck wasn't to noisy but the dual exhaust was behind the 60" sleeper and had tall pipes. A friend has a 2004 CV dump truck with a AI-427 and had all custome exhaust from turbo to exhaust tips. He had squeezed 5" pipe starting at the turbo ( hard to do in a CV, you now have to remove the turbo pipe to get at the #5 and #6 EUP) all the way to a 6" TEE then 6" dual straight pipes in place of the mufflers. It did run better but you couldn't listen to the raido or cell phone while goin down the road. After about 6 months he replaced the straiht pipes with mufflers but left the larger turbo pipe and Tee and said it still ran better than stock.

What year and model? Mack made the 427 from around 91/92 till 2007. Startin with the E-7 VMAC-I , VMAC-II, ETECH, CCRS, ASET AI and AC. Now the closest thin is the MP-8 425. All had good points and bad with some worse.

I was looking at a brand new 2011 CXU and GU on our lot and neither one had the air clutch assist on them. Guess the boss man ordered them without. Smart move.