AutomaticMack

I read these 10 commandments last night, and today I had quite the show today! One of those huge Michigan semi dump trains fell over while dumping near me, no one was hurt. No truck was pulled up next to it "per #4 of the commandments". The ten commandments maybe funny, but it is the truth. Drive safe ya'all

In my opinion Allison Transmissions are not "POS". And are a very good option to a manual, and they do increase resale value,mpg, off road abilities. I guess it all depends on the way you look at things, and your point of view.

WOW !! I didnt realize I was such a P.O.S.

I found this web site some people might be interested in. Its kinda cool to look up some of these companies safety records and such. Either use the DOT number or name etc. http://safer.fmcsa.dot.gov/CompanySnapshot.aspx

And if your a Ohio truck doing business in the great state of michigan, you will get pulled over on a daily basis. Just like me.....They keep pulling me over day after day on I-94 just west of detroit, but they cant get anything on this old MACK! Big difference between Ohio and michigan axle limits. Is it me or is michigan a corrupt money grubbing state?

Wow! sounds great to me!!! I would like to purchase one.!.!.!.!

On the 750 the modulator port is located on the drivers side behind the shift selector. It is either a push,pull, or electric switch. The push/pull models have a cable that connects to the throttle on the injector pump or throttle linkage. The electric models have a solenoid that connects to the side of the trans modulator port. Either the push/pull or electric allows the trans to know where the throttle is "Full,half,idle etc..." If the modulator cable was set incorrectly the trans would either shift too early or hang in gear way too long. Either case if the cable broke or came disconnected you could still shift it manually. I shift mine manually quite alot "Its Fun!!" On most push/pull type there is a length of thread and a nut connected to the linkage and you can adjust it either longer or shorter. Here is a link for a company that carries cables, might help ya. http://utxchange.com/Felsted%20Transmissio...or%20Cables.htm It is the same concept as a kick down cable on the old fords and chevy's way back in the day.

Thanks! I do hope this freshly rebuilt 4V runs as good and as reliable as the old 300 2v.

Oh boy! I just purchased a E6-350 4V today, because I could not locate a good EM6-300..... the old 300 has developed cracks on the bottom end near the dipstick tube. I hope this other engine will last a little while before it too cracks.

Thanks for the info!!

Well I guess its time for a different engine since the old EM6-300 2 valve developed a crack after a long reliable life. Now I am looking at two choices, either another EM6-300 or a E6-350. I have never drove the 350 4V and would like to know more about the 4V series. What is the torque range on the 350 etc.

Barry, I did some quick addition and came to the conclusion that there appears to be around 900 Members of BMT. WOW...... That is alot of people!

I am not sure about the new electronic Allison's, but the old all hydraulic models should to be at a complete stop to shift in and out of the low hole. Due to the huge gear difference between 1st. and 2nd gear (2nd is the gear the truck normally takes off in.) I have shifted them in and out while barely rolling, and not had a problem but its not recommended.

Ok, heres a thought....... I have a crack in a 85' EM6-300 2 Valve, However I have a good 1978 ENDT675. Can I swap the turbo,injectors,and pump, onto the 675......... turning the ol' 675 into a 300 and would I need to change the cam? Or could I use the 675 as a donor block? The only difference I can see, on the 675 the block has screw in freeze plugs, and the exhaust manifold bolts are horizontal versus the diagonal. And the injector pump is the older style. P.S. I went to a local junk yard that used to have about 100 old Mack's inside..... Well wouldn't ya know they crushed them all The ol' R Model is slowly passing away, but still kick'n butts.

The Allison Auto is probably not to blame for the poor mileage. I bet that new cat motor with the new low emission's engines is to blame. I know from experiance the latest greatest cats get really really poor mpg. And I also bet the Cummins is a non-emission's motor, and that would account the better milage. However alot depends on how a truck is spec'd. Thats my 2 cents. Every Allison I have ever come across gets better average fuel economy when compared to a manual. Considering of course when both trucks are driven properly. As for the HT-740 question, the HT-740 stands for 7 Series, with 4 forward gears. the HT-750DRD is a & series with five forward gears, one being a very low creeper. All the older HT 750,740,640 etc. where hydralic trans. None of the older trans are in production as of 2001 I think. The newer series 4060/4560 are the newer electronic series. For better or worse..........

About a year ago Allison and Mack had a rebate program if you purchased one. The cost of a Allison last year was about $15,000 however I think the rebate took off $7,000. I am not sure if that program is still available?

I have a quad axle 85 R686st with a HT 750DRD Allison. Mack and Allison make for a very strong set up !! It's a blast to drive on and off road. However I would stay away from those auto-shifts for any off road or dump truck use. With the older Allisons make sure your modulator cable is adjusted properly and change the fluid regularly. If and when I ever buy a new dump it would have an Allison.

An open letter to MACK Truck, Today I purchased a New 150 Amp Leece-Neville alternator for my 1985 R686 Dump Truck From Flag City Mack in Findlay Ohio. The orginal alternator was working good with 12 years of service however it was only a 100/105 amp output. My intent was to have more power for more electrical goodies. Well upon installing the new unit I discovered that at idle it was only outputing 11.0 volts with no load ("lights, AC, etc.") and when I crank it up to 1100 RPM the alternator would start outputing 14.01 volts. So I decided to take the bad out of the box unit back to Flag City Mack for a good one. Well it turns out Mack Corp. policy states that anything sold over the counter that is bad out of box needs to be sent in for replacement. And I would need to purchase another one at a price of $130.00 USD .......ok so that means I am out 260.00 and who knows if the second one is going to work. I contacted the Leece-Neville service rep. and he had me do some measurements while it was still on the truck, and YUP!!! its bad out of box! he suggested I either take it back, or get smaller pullies for the unit and not use the orginal pullies. After all this I decided to go to my local NAPA store and purchase a rebuilt alternator from them. wouldnt ya know it !! it worked !!!! I have talked to other Mack truck dealerships around the USA and all of them state it is Compay policy. That if a unit is bad out of box. Either be it a alternator fan clutch or any other part or parts installed by a customer. The customer must purchase another replacement and wait for a POSSIBLE? refund and no time frame? two months? year? who knows !!!. This is not customer service !!!!!!! This is out right Screwing of the loyal Mack customer!!!!!! A Loyal Mack Customer Tyler Y. Degree in Industrial Electricty Degree in Robotics

A few years ago I seen a R Model with a sliding back window behind the driver and pass seats. Does anyone have part numbers or any info on these were they sold by Mack ? Was this thing a cut down conversion of a pickup truck back window?

Heres the Allison manual

I do have a copy of the Allison Owners Manual for the 600 and 700 series trans. I copied from the Allison Corp. website a few years ago. It is in Adobe Acrobat format and zipped for quick email. Send me your email address and I send you a copy. Very good to have!

Howdy! The back up switch on that trans should be located on the passenger side. Forward and up a few inches of the dip stick tube. If I had to guess it has screw in plug and just needs to be unsrewed and screw the new switch in. It uses a hydralic pressure switch kinda like a brake light switch on the old ford cars and trucks. In a pinch I have used a pressure switch from a CAT front end loader. I would say contact United Transmission Exchange out there in Calf. and they will set ya up with the right switch for around 20 bucks or so +/- They are a wealth of info and parts. Oh I almost fergot, If there is fluid in the trans. dont remove the plug while the engine is off or all the fluid will pour out, Maybe if yer quick enuf with the installation you wont loose all your fluid. I usually leave the truck running shifter in "N" brakes set with chocks parked over the pit in the barn, and swap the switch out. With the truck at idle in "N" there will be no hyd. pressure applied the Reverse circuit in the trans. therefore no oil to come out. UTXchange.com Phone 1-800-527-1637 Fax 909-384-8145

I have an 85' R686 with a EM6-300 with a HT750DRD.... And lemme tell ya, it is hands down the best! Granted your not gonna get a speeding ticket on the highway top speed 65-70. Off road work is great and city mpg and performance is outstanding. Mack and Allison is a perfect combo! :

I had the same problem 4 years ago! Maybe issues like this should be turned into the National Highway Safety Administration

Anyone hear about the Hybrid Electric/Diesel Mack? Sounds kinda cool, but I wonder how much weight the electric stuff adds. Anyone know I would be interested in hearing about it.