M915A4R2 Build and Modification Thread

[simp5782]

So tweeking and modifying a few of these for commercial use.

Stock NTC400 Big Cam 1. HT3B turbo. AC. 6 Spd Allison 4500. Locked out of 6th gear though. 4.33 gears. 11R22.5s.

Stock with the unlocked TCM it will run 96mph at the 2450 governor.

Hauled grain up to 130gross today.

Step one for modifications - pump work, delete the aneroid. #10 button. 235 rail pressure. Dual fuel line system. Pyro and boost gauge as well.

Step two - air filter housing swap. The stock unit is a restricted part and the A2/3 truck filters are common with a better cfm.

Step three - ac condenser fan since it doesn't have one. Air bags on the front axle cause it's a bumpy sob. May swap the 385 65R22.5 for a wider stance and more flotation.

 

[silverstate55]

Yet another Simp5782 thread I’m subscribed to...interested in seeing if you can unlock 6th-gear in the transmission.

 

[simp5782]

Yet another Simp5782 thread I’m subscribed to...interested in seeing if you can unlock 6th-gear in the transmission.

It's been done that's why it can hit 95 other than the 61 it maxes out in direct 5th. It's basically a 915a1 without the unlock

 

[fuzzytoaster]

Yet another Simp5782 thread I’m subscribed to...interested in seeing if you can unlock 6th-gear in the transmission.

I submitted an "engineering request" to Freightliner with the vin and money to review the truck's specs and they gave permission for the rerate. Allison was capable of rerating, but didn't want to due to liability, so with Freightliner's approval they did it. Note: this is on a M915A4R2 which is different than the M915A4 before it. It should still work but is unverified at this time.

 

[simp5782]

Well the stock alternators are pretty crappy under heavy loads with extended idle times.

Stock alternator is 140amp 24v and 50amp 12v neihoffs.

Truck with blowers/AC on high, all lights on, flashers, trailer lights, transmission, AC condenser fans just basically overwhelms that 50amps that doesn't put out any juice till 1100rpms.

Decided to swap it out with a Delco 28SI 110amp 24v unit and use the Eaton Surepower Equalizer units. 28si has a remote sense as well.

Mounted the equalizer under the center console. 4 wires ran from the equalizer to the battery box. 1 - 24v 2- 12v 1- GND.

12v side has a disconnect and a resettable circuit breaker. 24v side has a resettable circuit breaker.

Upgraded the belt to a 2/9463PB dual V belt.

2 group 31 batteries run the system.

About a 5hr swap and modification time with wiring etc.

Debated about using a 12v alternator and starter but there are a few things that pull 24v from the fuse panel layout.

No load voltage at idle is 28v 13.7v
Full load voltage at idle is 28v 13.4v

 

[simp5782]

Pumps were rebuilt, aneroid deleted. #15 button. 275 rail pressure. Max egt is 1050 at sea level post turbo. Dual fuel line setup. Stock HT3B Turbo. Max boost is around 32/33psi.

According to the Allison DOC computer readout showing throttle, shift patterns, etc it the engine is putting out 1800ft/lbs of torque. It does not show HP output.

 

[m715mike]

What did you put on the terminals?

 

[simp5782]

What did you put on the terminals?

View attachment 868304

Grote Corrosion Preventative Sealant

99170 - Ultra Seal - Corrosion Preventative Sealant, 4 oz. (118 ml.) Tube

Grote Industries - Part: #99170 - Ultra Seal - Corrosion Preventative Sealant, 4 oz. (118 ml.) Tube. Good mechanical stability

www.grote.com

 

[simp5782]

DOC screenshot

 

[simp5782]

Since most folks don't like to ride in the bumpy sob there is no reason for a passengers side seat really.

Made a raised section for more storage and space. Things on the floor find their way under your feet pretty easy in the stock setup.

 

[simp5782]

Wheel seals tend to leak and have even had issues with the axle nuts backing off completely.

Use these stemco pro torque lock nuts instead.

 

[silverstate55]

When does the air-ride rear suspension go in?

 

[simp5782]

When does the air-ride rear suspension go in?

When it's not 105 outside

 

[chucky]

Wheel seals tend to leak and have even had issues with the axle nuts backing off completely.

Use these stemco pro torque lock nuts instead.

Is that a freightliner? Looks like a freightliner door .

 

[chucky]

When it's not 105 outside

What kind of air ride you going to use ? KW 8 BAG never impressed me at all for ride but the pete 4 bag seemed alot softer ride but nuway was the best ride ive ever run like being in a cadilac ! But i had a 86 walk=in w900 with reyco pulling pnumatic tanks that was in the running with the pete airide

 

[simp5782]

Is that a freightliner? Looks like a freightliner door .

FLD120

 

[chucky]

FLD120

Yea if i had started reading at the top of the thread i wood have seen the dash instead of starting at the last post !

 

[fuzzytoaster]

When does the air-ride rear suspension go in?

Look @silverstate55 .. the data plate has only so much space to write the nomenclature on after Simp is done with them. We are on M915A4R2E2-1.1

In all seriousness we've been considering trying it at some point in the future. A late 90's FLD120 rear chassis would fit it nicely.

 

[silverstate55]

Look @silverstate55 .. the data plate has only so much space to write the nomenclature on after Simp is done with them. We are on M915A4R2E2-1.1

In all seriousness we've been considering trying it at some point in the future. A late 90's FLD120 rear chassis would fit it nicely.

And plenty available at most truck wrecking yards nationwide….

 

[simp5782]

Only issue with the air ride swap and using axles from one is the gear ratios.. most are 3.55s to 3.90s.

The 915a4s use the same axles as the 915A0. A 4.44 so it would lose some of its low end grunt.

Top speed would increase about 17mph