Geoff Weeks

Cats of that vintage and 400 hp could be water aftercooled, that is one place it could be leaking. Coolant doesn't just disappear, so I would put some time into finding where it is going. head/spacer plate gasket is another. .6 OD puts a lot of heat (and power) into the transmission oil. You have a large OD and can drop the rear ratio quite a bit to move "in the mud", and still get down the highway at decent speed. My Marmon will top out at 80 with 4.11's and .78 OD, how much more do you need? If you have gears you can not use most of the time, but are paying a penalty for not having low enough gears at the same time, you are not making the most of what you have. Flying when empty, is a poor tradeoff for working well when loaded. Look at the total ratio, not the individual boxes, make the best compromise over the total ratio, so you are likely better off with a ratio that tops out at 80 mph but gives you a lower starting overall ratio.

Eaton ratio chart I often though of doing what you did, but installed 13's instead. B ratio is OD main, but I was going to go with U/D back. with .6 OD and 3.54's you are way over geared. With a 425 Cat and 4.11 gears with .78 od was about right.

the 150BMP uses a snap-ring in that location I believe.

I have not had the BM series apart, they sound like they are different then the 150 series.

BTW a place Cats like to loose coolant is the gear driven water pump weep hole, if that is were it is leaking, or if the weep hole is plugged up, it can force the coolant into the pan. Where is yours losing it from?

TBH, I did regular and heavy haul with Eaton trans. I drove a Mack 5 spd for a short while but never owned one. I would suggest going to Eatons site and downloading a ratio chart for what you have now, plot it out on a spread sheet for MPH at 1000, 1600 or 1700 and 2100 rpm for each gear to give you an idea what you are looking for. You already have the rear ratio for the math and Lo-pro 24.5 tires are about the same rev/mile as 11 22.5, 498-501 revs per mile. Do the same for any truck you are looking at or considering.

Eaton and Spicer (TTC) are twin countershaft transmission not triple. IFAIK Mack was the only one to use triple. You're unlikely to find a 2 spd in a used truck now, but any Eaton 402 equipped truck housings can accept a Eaton 2 spd center section. Eaton or Spicer/TTC 18's have lower ratios in the bottom end while still having O/D's on the top. Problem is with the deep reduction on the bottom, the driveline has to take all that torque.

The fact that it charges when connected is a good clue, how did you connect? to which terminal? I think you are going to need someone who knows the wiring on that model, but I would trace the output wire back to where it connects to the battery (often at the starter motor) and look for a fuseable link in the wire. It will likely be in the first few inches at the starter end (battery supply end) if it has one.

Alternator output is not generally fused, as the voltage spike of dumping the load can damage anything still connected. I have seen fuseable links used between the battery and alternator, but not between it and the rest of the electrical system. I don't know about the truck in question exactly, but I would tend to doubt more than a fuseable link. Is the 12 volts present at the output stud with the engine off? What are the problems?

If you get jammed up real bad, here is one, may or may not need your drive on it.Air Starter.

Which bolt has a reverse thread? I can't think of one off the top of my head? Yours is slightly different then the 150's but I don't know of any LH threads on them.

Not much to them, if you can fix your air impact gun, you can work on an air starter.

100# for 7 months? wow, you've got a tight system, I thought mine was good a 4 months and enough are to start.

From his first post, he states no "water" in the oil. There may be blow-by, they may be coolant in the oil he hasn't yet seen, but at present, I wouldn't condemn the engine.

Delphi FL2914 Ebay or your local Autoparts store.

OK they are Mack then.

Well, you have the prescription on how to make a million in trucking down... Start with 2 million!

I was expecting a FC which I think they did put a 5th wheel on one variant.

Are the rears Mack (Top loaders, center section bolt in from the top, or front loaders, bolt in from the front)?

Well, I took that info and went to a junkyard when I was doing my swap. Eaton and Rockwell (Meritor) used common wheel end parts so the bearing and seals as well as bearing spacing were the same. I know Spicer (IHC) use different bearings and spacing on their 12K steers. I have no idea what Mack uses. A junkyard is likely a better place to go than the dealer and new parts. They often know interchange info. In my case hubs off a Ford would work if I changed the outer bearing. In my case the rear axle were common 40K Eaton and IHC's which all take the same stuff as Rockwells also at the 40K level. What rears do you have? What front (steer axle) do you have. Hub Pilot came into being ten years after your truck was made, if the axle models were still in use in the 1990's then you have a good chance that the hubs are available. Many of the Mack's I worked on had heavy front axles, so 5x 16.5 or larger brakes, and heavier bearings than the 12K axles on my tractors.

Info that is going to be helpful is inner cone # outer cone # seal number, brake size. Axle capacity if you know it. That is all I used when changing from stud pilot to spoke.

Wiki has a pretty good definition.

In OTR trucking in this country the weight would be a problem. In buses you likely wouldn't have a problem with an extra 700 lbs, firetruck not a problem, garbage packer maybe or maybe not. I guess that is why they weren't a big seller here. In a country where far too many drivers look a a jake as a noise maker to startle people, they would have no attraction. Your likely looking at a similar weight penalty with a Cat brakesaver, and they were never very big sellers either. With the fact the engine can be ordered OEM with the brakesaver likely made them an easier sell then the Telma which would be a separate sale.

The ones (Telmas) I was around were on LP fueled M.A.N.'s so had a throttle and therefore would not work with a Jake. However if you could justify the weight there is no reason they couldn't be used with an engine Jake as well. Some of the heavy hauler had 3406's with both Jake and Brakesaver, as weight is never an issue when every load is a permit load. I don't know how much they weighed, but there was big rotor on the output (transmission) or input (rear axle) and a stator that surrounds the rotor with a series of electro-magnets in it. So lots of copper and iron. Brakesaver used engine oil to act on a turbine wheel between the engine and clutch. Retarding energy was turned into heat in the engine oil. Cats with Brakesavers have bigger oil coolers then those without. When Cat used an injection pump and nozzles in the head, there wasn't a handy injector rocker to time the Jake like there was with Cummins and 2 stroke Detroits for optimal valve opening. Cat Jake's of that period used an adjacent cyl exhaust rocker to trip the Jake, but its timing wasn't ideal so the retarding wasn't as good as it is with common rail engines. So that is why the Brakesaver hung around until the changes over to common rail fueling. At that point the timing came from the injector rocker, like Cummins. By the time we got the LP buses, mostly the Telam's didn't work, we had enough to do to keep the buses running and Telma's weren't needed in Chicago like they were in Austria where the buses came from. I think may be 1 out of 4 or so worked. Likely needed something simple, but there was never time.

Telma's were more often found on buses. 1) they are silent, so not to alarm passengers, 2) they are heavy. Buses usually have less trouble keeping on the good side of weight law. 3) they are electric and can suffer from the gremlins common to high current electrical devices. Cats "Brake saver" was hyd with engine oil being the medium used. It was heavy when compared to a Jake or Macks retarder. The reason for it went away when Cat (and others) changed to common-rail injection.