mudslut28

LOL For a while there Im surprised Wal-Mart didnt have 2 valve Mack parts. You could and for the most part still can buy em anywhere.

I wouldnt worry too much about that 4 valve. I got a new one in 88 and it is still running every day and has been rebuilt once...amazing motor!

HK ..did you ever have any luck with the 2090's? I had one that was a constant headache. I always thought that thing was one of Macks worse ideas. Mack 688...beware..if the clutch pack is down..they arent cheap.

As always H-K is on the mark here. My 76 dm800 gets 85w-140 in the 6 speed tranny and the 65k rears. The 92 gets 50 wt for the 14708LL tranny and 85w-140 for the 58k rears. I actually use Redline Racing Syn for the Eaton/Fuller with some RL friction modifier in it and regular Valvo for the rears. I think Mack rears would live with swampwater in them..lol. The jury is still out on this E/F 8 spd though...not sure how the reliability is gonna be. Im used to putting a clutch in front of the 6 and 7 speeds every 5 or 6 years and never touching them.

Like I said..not exactly sure how they work..but that brakesaver is one sweet invention.

The brakesaver is a flywheel engine braking system. Im not sure exactly how they work...but they are one sweet setup when hauling on hills. I had a friend who bought a new 1996 RD800 with a 3406C with one of those and the super jake. It was amazing downhill.

Thats exactly what I was looking for!! Thank you!! Close to what I had thought. I always just called em 2 valves and 4 valves..lol.

I have been around Macks all my life. With that being said I still really dont know what model is which when it comes to motors. Only ones Im sure of are the E6 and E7 4v's..lol. I always just called em 2 valve motors. My old Mack has a 2v 300?? 285? and I have a spare motor which is a 235 (237) that was made in 86. So can anybody fill me in on what the differences in the 673, 675 and 676 etc would be? Thanks in advance.

Thats what Im thinking. Back in the day? Hell most of em are still going. Again simplicity is brilliance.

Ok, Im extremely biased here...but that thing is an absolute work of art!!! You guys are looking at the toughest truck to ever roll off an assembly line....PERIOD!!! My 76 Model still hauls every day. The coalfields are still full of these beasts hauling their 45-50 tons a trip everyday. I have gotta ask if the cab was pretty solid before starting or if you replaced it? Thats about the only thing mine needs and I do plan on restoring it at some point. Only thing the one pictured needs is a nice big chrome double bumper and brush guard. Your friend could probably name his price for that thing down in this area. Im in love!! LOL I just wish i could go buy a new DM800....lots of folks do. Bascially the only way you could hurt one is if you are just trying to (and even then its tough) or to wreck it...lol. I have roade my ol 800 out of the poorhouse on more than one occasion.

I gotta agree with the "watch your gauges" sayings here. I have never needed an ear piercing alarm and a bunch of lights to see if the motor is getting hot. Any decent driver checks his/her oil/water on a regular basis. Thankfully the previous owner had all the shutdowns disabled except whent he low air buzzer is still on my "new" 92 model. Showdog I had an 86 RD 800 that had an E7 400 Mechanical installed in it for a short time. In my experience the computer motors seemed to run a lot stronger than the mechanicals but that is just a 3-4 truck comparison so it may not be the norm. The E7 400 "puter" motor in my r model now runs like a raped ape...Im pretty darned impressed with the power to say the least. I really couldnt blame ya for wanting to get rid of anything electronic though...Im old school as well. I'd imagine I'd probably do it if it gave me much trouble as well...but I hope it dont hehehe.

Well I got it and got it installed. Hauled 2 loads and the shutdown light and buzzer started coming on. The shutdown has been shut off (LMAO) on this truck so I went ahead and dumped the load and started checking the truck out. Oil and water level fine...when I finally found out what had caused it...one of the wires on the water level sensor was either too tight or too loose. So I took it off put it back on and tightened it down again and no more trouble..lol. No wonder the shutdown has been disabled. This is my first computer motor. Powerwise its an absolute beast and I love everything about the truck...but I dunno bout something that finicky..lol. Being my first E7 i definitely like it better than the E6 and the 2 valves so far except for the uneasiness about the computer. I guess anything new is scary...lol. The engine brake is a lot better than my other Macks and the power...lol...it dont feel like a Mack...

Thats what Im saying as well Barry...the sad thing is they are about the only Mack dealer within 300 miles. They bought out all the other dealers. They got a nice monopoly down here. As I said..they are fairly useless... a lot of people got away from Macks because of them.

Repairing the old one for a spare is a definite if possible. Im not going through this again..lol.

My new to me 92 R Model has an E7-400. The darned surge tank is leaking and has me down. It doesnt seem like there is a new spare in existence! An outfit and big (and useless) as Worldwide has 5 in their whole system. I was sent on a wild goose chase today to get one of those and they mysteriously couldnt locate it once I arrived...grrrrr... Barry, whats the deal on these things? Do they not tear up much or is their a big run on them or soemthing..lol.

I can tell you I just bought another truck to haul coal in and it had to be a Mack and it had to be pre-98. As far as what we'd rather see...Mack is disappearing right in front of our own eyes... Volvo=Cancer

Sc**w the junk...bring back the 800's!!!

LOL I usually keep a few in my 800. In fact I crushed one with the air seat once...yeeech..lol. I like the soap ideas...I dont care much for the anti-freeze one because they will just die in my truck where I cant find em.....yeeech again..lol.

LOL I have 2 worn out destroyed 6 speeds out there and like to never found a replacement a couple of years ago when the bearings got so bad they started causing gear failure. I ended up putting one with a fine spline tail shaft in which created a lot of issues in itself. Those things are hard to find around here. If you want a strong tranny with a TALL overdrive ratio try a T2070 7 speed. High gear is .60. My 88 had a 7 speed with 7.58 ratio 65k rears and would top out at 62mph. Can anyone tell me what the deal was with the fine spline tailshafts on some of the 6 speeds? Is it something changed for the later models? It sure is almost impossible to find a fine spline flat yoke for the back of one of them. Had to use a normal yoke and go to a 1810 series ujoint as opposed to the 324 mechanical joint they originally had.

Ok guys these were a little ahead of my time but did you really have to shift both sticks at the same time or am I just confusing myself?

It definitely looks to be a 6 speed. Im with Rick though need a little closer look.

Hang in there Bulldog...If you want to bad enough it will be yours. You already know how to make it happen just have a little patience. If a feller is still willing to work hard and gut it out the world can still be his oyster. Them old dogs will never let you down either. Glad to know Im not the only one out there without a life...lol. But it definitely gets in the blood. I can see the day when I dont truck anymore..but I cant ever see the day of not having at least one of my dogs.

Both of my dm's have 20k front axles with the single steering box. I can say I have seen plain ol double framed 44 rear r models and superliners etc pulling 150k of coal with pretty good reliability for a long time right up till the new weight laws were passed. If its fairly flat and you have decent drivers I dont really think you'd need anything special as they have been doing it for 30 years or so here in the steep appalachia coalfields. Nobody used double jacks or floats and most front axles were not the 20k's.

Thanks Rick I had wondered this myself.

My 800 has them..but I couldnt tell you where to find them now. Good luck in your search.