Lmackattack

Yep. the 6 speed will give you one lower forward gear and 5 reverse gears. top end stays the same as your 5 speed. the 6 speed comes in 2 stick or air shift. There are a few versions of 6 speeds,you will need the one HK just mentioned. If you want to increase road speed you will have to look for transmissions that work well with the Maxidynes, A 12 speed is a option but they are getting hard to find.

and he was going nice and steady like a good drive would. no throttle revs? must have been a weak joint? front end was looking a little light. Glad his brakes held!!!!!!!

Nice find!! Hope you gave it a good home?

My B model with a Quad and 5.73 is geared for 62MPH. I think thats at 2100RPM. I could likely get 65MPH @2300 but its never left the yard! LOL Trent

its got to be a mack triple countershaft........Mack 12 speeds would seam right to do the job??

Gambi..If you have a matched set your fine. The diffrence is that when the tires are of diffrent sizes the Diff spider gears are compensating by spinning all the time. Its normal in a turn to have those gears spin on a open axel but just driving down the highway it puts more wear on them when they should be doing very little. The power divider will also wear out as the rear axel may be slower than the front (or vise versa). the Divider components will try to compensate for the speed diffrence and wear early as they should not be needed when driving down the highway. I notice some old macks can spin all 4 corners in the mud on a rebuilt tight drive line where worn out rears will spin 1-2 wheels and the powerdivider may not lock in as it should. Herb, please Correct me if im worng but with macks power divider you only get 2 drive wheels "locked" in? One wheel on the FR and the other on the RR axel? With a diff lock and power divider you should have 3 wheels locked in? Trent

looks to be geared for 55-60MPH depending on the overdrive ratio. HP in that range will pull fine on the flats but you will be downshifting in the hills. the 250 HP thermodynes did good for there time but the maxidynes soon took over.

nice pics John. I really like that old dog. Whats with the new weight laws in your state?

I converted my RS700L from manual to power sterring. I had to locate a pump,sterring box, resivor and lines. also needed a diffrent sterring shaft as it was to long or short with the new power steering box. I had to drill a few holes in the rail to mount and make a few large washers to get it flush on the frame rail. Not a bad job to do one weekend. Trent

and at that rate just keep it stock as the 12 speed was one of the first Mack air shift boxes that worked well. One thing I have never heard was if the clutch packs were better on the 12speeds vs the 9 speeds

FJH will know more about the problems in 04 but if I recall low power, Elictrical issues and Turbos? Turbos were on back order all over the place> I recall many had to wait 2-3 weeks to get a reman turbo. Many Mack Shops would over stock them if they cold get their hands on them and try to keep them off the "system" so they would have them in stock to support the local owners. It was not a mack problem but the turbo MFG was making them look very bad with no spare turbos. Electical troubles, Derate, trucks just shutting off, Not good and around here,lots of old mack owners went to other truck MFG soon after. Low power from emission issues. the engines would just start to come alive and pull then you had to shift. No throttle responce. it was like driving a large truck with a gas engine... this was my experince with the 04 models

I had mack boots about 10 years ago. I had both the black and tan leather. came in a green/black and red box had the old Mack logo with the "correct dog" on the emblem. they also lasted me 3-4 years before they were worn out. I used them every day at UPS working the docks walking on steel grates. Havent seen the new boots

hmm. on all the air lock power dividers I have used all you had to do was get some slack in the drive train to have it release. If I had it in and was going through mud then exit on to a street, the PD would unlock as soon as I let off the power or the truck coasted a little.(switch in the off position) Backing up will also do the trick but I have never had to as long as I unloaded the stress on the drive line and was not in a turn.? most times I turned it off 10' before I hit the pavement unless I needed it to get out. A few rules I have learned and told about with air power dividers..... never put it in with the tires spinning Most times the truck should be stopped or rolling in a straight line at slow speeds to put it in. dont drive on pavment with it in turn off before you reach hi speeds. dont put in at high speeds. tire size across the axel is important but hurb had just pointed out a great example that I did not know about mack power dividers.(thanks Herb)

Lets see. 1st you have the hi lo range shifter that is used with the clutch packs then you have the Low Low "dash switch" to use the lowest gear in the box. then you have the Reverse sshifter. all of these would have to be figured out in the shift pattern. Even if you removed the clutch packs you still have to find a way to get all the gears to slide around to enguage or not enguage. Money talks but its not really worth it to get 2 sticks from it as it works pretty darn good as it is. I always say its one of the best boxes Mack ever put behind a maxidyne.

10-4 fred. The 440 V8 at the yard holds around 26-28PSI. I think its a 1991 model? on a good pull I figured it should be close to that psi?

at one time the gold dog was to show the truck was 100% Mack drivetrain. I think that changed in the mid 80s? I herd Recently it has been brought back to represent a 100% mack drive train?

you dont have boost! 22 psi is a low side I think 25-30 would be what you shoul see. My straight 6 285 will pump out 28-30PSI in the cold. this is with the pump turned up a little.

I have yet to see a air shift 12 speed converted to a 2 stick. I dont think they were ever set up for manual linkage so it wont work. The older 6 speeds had the shift cover do all the work in the aux box so it could be manual or air depending on the cover you installed. I like 2 stick transmissions but I think the 12 speed with its clutch packs and short splits that work the aux box is beeter suited with air. let us know if you find more info on this...

I like how steep of an angle I can get my frameless and never have to shovel stuff out but then again always liked the safty factor of the 1/4 frame. as long as I dont have a frame trailer ,,Im all good.

if that pin broke that will be the first place to start. depending how long its been broken will depend if it wore down the pads and trunion bushings

I see one small problem.. We need a few pics of this project!!!!

It can be a number of things Worn pads, worn trunion bushings can cause the rears to walk. also bad control rods can add to them walking more. do the springs slide side to side? It could also be a bad end cap that has let a spring wear into the metal. The 2 control rods (one from the top of each diff housing to the trunion/crossmember) hold the diffs upright and control the torque input from the driveshafts. the 1 control rod on the rear rear diff is there to help hold the axels from walking. All the trucks I have seen had only one of these rods and it was on the rear rear axel. If this rod is worn out it will also cause the axels to walk. that rod was intended to help keep the axels in place on hard turns. Trent

I need to get my Dump trailer painted but I need to get the sides up about 6" I Figure I should add the sides first before I go and blast the traler for paint. looking for a 6" tall / 3" wide by 20' long. could be in 10' sections but need a total of 40' prefer used as its cheeper. can have some dents as it will get beat up anyways. if you are close to Chicago and know of any let me know. Also been thinking of finding a used 36" ablebody sleeper to put back on the truck. Mine had one from the factory but someone removed it years ago.. a few winter projects for me.... let me know Thanks Trent Chicago IL

wow .. thats a project LOL!! i wish you luck with it. thats alot of things to get lined up right. It sounds like you will be better off making some of the mounts rather than trying to get the diffrent parts to work for you??? regards Trent

If I recall correctly a R700 mount is a little diffrent than a 73+ RS700 mounts. as the later RS cabs sat higher above the fram than early models. same with Valueliners as those cabs also sit higher. As rob said the RS600-valuliner and later RS700L all had straight rails. the diffrence could be the mount or where the mount holes were drilled. I think most of the later cabs used the same style but they could be a little diffrent depending on the model of the truck. simple way to check cab hight is to look at the back of the cab. if the cab rear wall is about flush with the top of the frame rails. that could be a standard R model. if it sits about 6" above the rails the cab is "raised". Early Fuel tanks also used the front or rear or both cab mounts as a support so that may come into play? are you converting a R600 to a R700? Trent