Brandt

99.89% of the time I leave the stick in N when I shut it off. This time I was parked on a steep grade and decided to leave it in gear. I just reached in to start it because the ground dropped away and would have required a 4' step/climb to get all the way in. I sure wish it would have lurched when I put juice to the starter, but it didn't. 15 minutes later, when I returned, the damage was done. Maybe if I wasn't as deaf as a post I would have heard a grinding noise from where I was working, but w/o hearing aids in and more than likely ear plugs in - not a chance of me hearing anything!

Yup, P/Ns, pictures, advice, VINs. At this point anything will help!

After I broke my 1070 12 speed, I decided to replace it with an RTLO 15 speed. The shop is running into many problems with the bell housing/motor mounts. The local Mack dealer is clueless on old stuff and stuff that he can't use the VIN to get parts. I will probably give my mechanic access to my BMT account so that I can get out of the middle and let knowledgeable people figure this out. If anybody has done this before, I (we) are all ears!! 1991 RD 690 EM7 Maxidyne. Mack top loader diffs. This is how it all started:

Air is getting to the trans. Bought a 15 spd for it. It will be Nov before I get it in. Is the broken 1070B worth anything??

I didn't hear anything when I was rotating the knob around. When I engaged the Deep Reduction, I heard nothing until I moved the stick into 1st gear. Then I heard a clunk and the stick was locked in the 1st gear position. You can probably tell by my terminology that I am only marginally mechanically inclined. When I look at those pix of a transmission, my head starts to hurt. I still think there is some voodoo that makes a differential work! The cab is air supported in the back, but I have my hydraulic tank behind the cab to make things more difficult.

I started the truck up to build air and forgot that I had left it in gear when I shut it off several days before. Once air was built I went over to it and heard a grinding sound. I realized what I had done and pulled it out of gear. Now I have no movement at all. No forward movement, No reverse movement, no deeprange movement. What did I FU now!!! How expensive is this fix gonna be??

I noticed this and just thought they were farm trucks running hay in ID. I see a bunch in ID and now have started seeing them in MT and ND too.

I noticed this and just thought they were farm trucks running hay in ID. I see a bunch in ID and now have started seeing them in MT and ND too.

I noticed this and just thought they were farm trucks running hay in ID. I see a bunch in ID and now have started seeing them in MT and ND too.

It would be nice to find one of them, except you guys put the steering wheel on the wrong side. 😁😁

WOW!! Those are some low numbers. Like looking for a needle in a haystack. Guess I'll start looking for a MH with a Series 60

Sputtering is still there when the engine temp is low. It seems to go away after the gauge hits 160*. Fuel issue went away after I changed the nearly 30 year old fuel lines. Seems they were collapsing under a load.

I have seen some older Macks with Detroit 92/71 series engines and Cummins Big and Small Cam engines in them. Once the engines went electronic did Mack use other than Mack engines?? Did a Series 60 Detroit or N-14 Cummins ever make it into a Mack??

What drives my speedo and where do I find it?? For the last year my speedo has been working when it wants too. Sometimes reading properly and sometimes showing 15mph when I'm at highway speeds. This also goofs with my odometer as I have only gone 550 miles in the last 9 months. I looked on the trans and found no cable driven port. Is it air?? Electric?? Does the cable come off of the top?? 1991 RD 690 TRTXL1070B - 12 spd w/.78 OD CRDPC92 & CRD93 diffs with SS440C axles It is due for a triple box oil change. I am going to run Amsoil in the trans and diffs. What weight do I need in each?? What is the capacity of each? It looks like the trans has 2 drain plugs - is that correct?

I bought a spare housing from Mack in case I crushed mine. I turned like there was no tomorrow and it loosened up and came off w/o crushing. Mack took the part back and I am $97 richer!! Thanks guys.

It is stuck on there good. It's gonna take lots of Kroil and some heat.

How do I get the centrifuge oil housing off to replace the element???? Last time I skipped it, but I can't do that again! EM 7 300HP Maxadyne

Finally got the high flow injectors (ADSKBAL137P26HFEX) and turbo (SCH174828) in. The truck runs a bunch better!! Before, my empty mpg was 7.4 to 7.5. Now my mpg is 7.2, but that is 50% empty and 50% loaded at 62K. The most boost I saw was 27psi, but 22 psi seemed the norm. Empty I was pulling 9 psi to maintain 60 mph. EGTs ran about 800, but did spike at 1000 on a 4 mile grade. These are after the turbo readings. I still have 2 problems with it. Before it reaches operating temp, it still sputters and stamers. Once the temp gauge hits 180 it goes away. I thought this was injectors, but after the new injectors the problem remains. The other problem is that in a long pull while loaded, I hear pops and sputterings from the exhaust. I also watch the boost go from 25 to 18, to 23 to 20 and bounce around synchronized with the pops and sputtering. I have done nothing to the fuel pump. I even hesitate writing this because the truck is due for a fuel filter change and it might just be filters. If it is not filters - Am I over fueling it?? Under fueling it?? I have driven electronic engines 98% of my life - what does a fuel pressure gauge tell me and do I need one?? Because I am kinda ignorant on mechanical engines - yesterday I was tooling around at 62K on the flats at low rpm (1000-1300). Does this over heat the pistons?? Cause pistons to crack?? Anything bad? I was pulling 15 psi boost and 800* exhaust temp. My load point and dump point were about 4 miles apart , I wasn't on the throttle very hard as most of it was on a dirt road and there was no traffic that I was holding up. I don't think I made it into top gear all day.

Seems the 315/80/22.5 are the same size as the 12Rs. Good to know info.

Can I run 12Rs on an 8.25" rim or does it need a 9" rim?? The OEM injector # is 736GB343P3. I have a Turbo #, but Google turns up zero info on it. When I'm empty I run the low side of the gears until I reach the top on, then split to the high side. When loaded, I might run the low side for the first shift, then I split them all the way up. I generally shift around 16-1700, as I am conditioned to shift low due to the 1.5 mil electronic engine miles I've done. I don't know what this engine is governed at as I've never ran it up that high to find out. Found the old shop info, it is Antrim Diesel in western PA.

There is only 225K miles and 12K hours on this truck. It was a county plow truck and seems to have a lot of idle hours. I do have to remind myself that it is not a Series 60 and won't go for a million. The build sheet shows: EM7-300L-4VH 1425 lbs-ft TRTXL1070B - 12 spd w/.78 OD CRDPC92 & CRD93 diffs with SS440C axles I would much prefer 4.17 gears, but I don't think I'll ever recoup the cost in fuel savings. With Dayton hubs, I'm kinda stuck with 11R-22.5 tires

OK, 400 is out of reach. I am not familiar with the differences between the Maxi, Econo, Thermo power curves. I can live with 350. I'm just wanting to gain as much as I "reasonably" can due to the increase in weight that I will be pulling. I have a 12 spd behind it with 4.42 gears. I think the 12 psd is a 1050TX???

I have a '91 EM7 300 Maxidyne that has 2 or maybe 3 failing injectors. This was a transitional year and it is all mechanical except for the elec fuel pump. I was told that I could upgrade the injectors and turbo (at the same time) and possibly achieve 400 HP. I have lost contact with this source, but am ready to do the upgrade. Where do I find out what part numbers I need for the inj and what model turbo. The truck works at 4900'-5900' elev and I plan on adding a pup to it. Gross will be around 88-91K depending on how long my pup tongue is.

OK, Thanx

What is the difference when an axle is called a "pusher" or a "tag". I'm wanting to put one in FRONT of my drive axles. I need steerable and a drop axle to clear the drive shaft.