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M-Drive


Threedog

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I just started driving a Mack Pinnacle with a MP8 505 engine and M-Drive transmission. This is the first time I have run a truck with one of the new automated ones and like it so far. I was worried about starting power where I haul a set of trains and gross 138,000lbs but so far there has been no problems. I am just wondering if there is anyone else running an M-Drive and if any niggles or problems are popping up.

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I've made 2 trips across the hills on the PA Turnpike with gross weights in the 50-60k range. I was very impressed with the smothness of the tranny and the pulling power of the MP7-395. I also thought it worked very well in slow maneuvers.

We haul LTL freight in vans and the only complaint I've heard is that it it's a little rough when hauling liquid totes. it cannot shift with the surge the way a driver with a manual trans can.

Jim

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A customer of ours just got 2 CHN Macks with M-Drive.They haul milk tankers and after 2 weeks with the trucks are very impressed with them.The smooth shifts are critical for slosh loads as you know.The drivers tell me the shifts are super smooth,even under full power climbing hills.I'll get some pics soon,nice looking trucks.Love the axle forward. Steve

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everything ive heard people like the m drive. i talked to a logger that tried one out and he said he would deffinately buy one . he had 125k lb load and it worked great up and down hill. he currently has a chu with a 505 18 spd and has no complaint with that

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WE are in the process of delivering 16 2014 CXU613 56" flat tops with MP8-445, 12 speed M-Drive "direct" and 2.64 rear end gears to a tanker fleet. Beautiful trucks - drove one yesterday for about 20 miles - smooth as silk.

I test drove the Super Econodyne at Louisville truck show with a smooth bore tanker loaded.It shifted great.The drivetrain engineer said I should spec with 12spd O.D.with 2:69 rears.My dealer says 12spd O.D. with 3:25 rears.Kevin Rutherford and Bruce say maybe 12spd Direct with 2:50 or 2:59 rears.I would like to run the 505 hp,1760ftlbs and get 7 to 7.5 mpg.I run 62 to 65mph from Il to Columbia SC via Atlanta.I see Freightliner is going with the 12spd auto Direct with 2:50's.

Edited by LSI
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Direct top gear has more rwhp and tq the higher the top gear ratio in the trans the lower the torque multiplication. I would build one with a direct top gear 10 spd, MP8 505, and somewhere in the 2.50-2.70 rears. I would be looking for a cruising rpm of about 1400, if you have that kind of engine HP and tq and a direct trans you should get great MPG. I have asked why the Super Econodyne has an OD top gear trans and was told it was because they didn't have a direct. Take two identical trucks same engine same body/frame/weight, put an OD and 3:42 gears in one and a direct and 2:60 gears in the other. The direct truck will pull better and get better MPG because its not turning the drive shaft faster than the input which adds a lot of resistance thus making less rwhp/tq. Make sense? Turn your trans output shaft the same speed as the input or 1:1 direct you make more rwhp/tq, try it in the truck you have now. Take your truck out on the road with an OD trans and run it for a while in direct in most 9/10spds that's one gear down in a 13/18 its one whole gear down in high, keep the rpm down to about 14-1450 I bet it pulls better than in OD at that rpm. Of course at higher speeds you get more aerodynamic drag and rolling resistance but you'll get the basic idea. If you have a hill you go over often that drags you down go ahead and slow down before you start up it and go into direct in most cases you'll pull it out or wait much longer to drop a gear due to the higher rwhp/tq. Oh and for mileage id go with low pro 24.5 tires, 22.5's are great and 11R22.5's s are the same diameter, however the taller the sidewall the more rolling resistance so shorter sidewalls equal better MPG. The short sidewall concept works with low pro 22.5's too but also consider the friction of the differentials,axles and wheel bearings, with taller tires the axles turn slower creating less friction thus more MPG. Ok that's all for tonight I'm out.

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"Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin

"If your gonna be STUPID, you gotta be TOUGH"

"You cant always get what you want, but if you try sometimes you get what you need"

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I drove the Super Econodyne packaage about 3 months ago - very nice set up. WE demonstrated an M-Drive with a 12 speed OD and 3.08 gears for a customer hauliung 50k+ on flatbeds - they loved it. I like the direct drive, but once you get over 1550 ft lbs you have to go up the the 16210C or higher if you want to stay with the 10 speed.to handle the torque - all OD transmissions. M-Drive/I-Shift is a game changer for fleet business.

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  • 2 weeks later...

Well after a month with the M-Drive I am absoulutely loving it. It took a little getting used to it pulling down to 1100 on a hill but now I don't pay any attention to it. I just drive and let the machine do the work. If I was to buy my own truck it definately would be a Mack with M-Drive.

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So the lower the rpm and the higher the mph = better MPGs ? !

Well than why run 1400-1600rpm, When 700-900rpm would be better ? !

If 1400rpm = 7.5mpg, and 2000rpm = 4.5mpgs. Than 800rpm should get about 9mpg's ? !

Technology has certainly advanced beyond my comprehension. If I ran any of the trucks I drove at 1400rpm I'd get kicked off the highway. Most wouldn't last very long operating below 1500rpm either. 2.xx gears ? ! Ha ! They barely did the job with 4.33 and 4.88 gear ratios !

Mike

1953 REO M48.

1962 GMC 3000.

1969 AMC AMX-390.

1983 AMC Eagle SX/4.

1988 AMC Jeep Comanche.

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Thanks go to electronics and variable geometry turbos.

 

So nothing built today plays by the rules learned on 1950s-1980s trucks than ? !

The never below 1500rpm and never over 2150rpm rule is out the window ? !

No more ring glazing ? ! No more blown head gaskets ? ! All brands can now be driven as if they were Maxidyne's, Ran at 1250rpm-2250rpm, and maxed out at 2375rpm ? !

Mike

1953 REO M48.

1962 GMC 3000.

1969 AMC AMX-390.

1983 AMC Eagle SX/4.

1988 AMC Jeep Comanche.

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2375rpm? Whew.. I got scared just reading that, I don't think I've ever topped 2100 I try to stay under 1900 most times. I only get to 1800 in the top three gears with a load trying to up shift. I guess that's the thing about being used to high HP and tq, you get used to running it up just enough to be able to shift and it pulls it up every time.

"Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin

"If your gonna be STUPID, you gotta be TOUGH"

"You cant always get what you want, but if you try sometimes you get what you need"

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Must be nice, I'm poor so I drive antiques. I ran a V300 or P1525 Cummins 785 V8 they are a screaming machine. I actually rebuilt one and got to see it run on the dyno 317hp@3,300rpm and 595tq@2,600rpm !

Yep it was a wonderful boat anchor, up shift at 3100-3300rpm and down shift at 2000-2200rpm or other wise you'd come down the hills in reverse ;o)

When I rode with the guys running the Mack's they spun them out to 2100-2300rpm all the time, idle out the drive way to the paved road. Once on the asphalt they slam them to the floor pound through all 5 or 7spd's.

Mike

1953 REO M48.

1962 GMC 3000.

1969 AMC AMX-390.

1983 AMC Eagle SX/4.

1988 AMC Jeep Comanche.

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Thats how the first Mack I rode in got driven, and it was a friends uncle that was probably 50-55 then and he held it till it wouldnt turn any more then shifted, I started driving and did the same thing till I realized theyll do the same job with half the rpm and last a lot longer.

"Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin

"If your gonna be STUPID, you gotta be TOUGH"

"You cant always get what you want, but if you try sometimes you get what you need"

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My great uncle has 2 1975 Mack's an M52a1 tractor and an M54a1 cargo. 355hp Mack diesels, 7spd Mack transmission's, with 6.38 gear ratios, and 12R24.5 tires. They run 70mph@2,000rpm in OD according to GPS ;o)

Two very strong pulling trucks, They sure guzzle fuel though !

Mike

1953 REO M48.

1962 GMC 3000.

1969 AMC AMX-390.

1983 AMC Eagle SX/4.

1988 AMC Jeep Comanche.

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I would love to have a running Mack cargo, I always find Reo's when I look.

"Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin

"If your gonna be STUPID, you gotta be TOUGH"

"You cant always get what you want, but if you try sometimes you get what you need"

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Well there are 2 different Macks one is Mack powered ENDT-673, with Spicer trans and rockwell's. The other unit is a Mack built unit which has all Mack running gear and a ENDT-673C.

A1's were the Mack powered/Mack built trucks. The A2s were Multifuels, and stand M50s were gasser's. Of course the reman's could have been any of them swapped to or rebuilt at a2 spec's.

The old timer, reconfigured his trucks as they were altered. So he built what he calls the "a3 series" ups them to a 355hp Maxidyne, replaces the 5spd's with a 7spd, and swap's out the 11.00-20s with 12R24.5s. Now he has all the pulling power he'll ever need and some good road speed too.

I asked him to join up a few times.

Mike

1953 REO M48.

1962 GMC 3000.

1969 AMC AMX-390.

1983 AMC Eagle SX/4.

1988 AMC Jeep Comanche.

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