The Mega Hauler

On the fan clutch, does it have a complete fan and shroud? Does it overheat at idle on a hot day with the AC running? I mean, 220 isn't hot.

On the other issues you just raised, what is your rear axle weight?
 
On the fan clutch, does it have a complete fan and shroud? Does it overheat at idle on a hot day with the AC running? I mean, 220 isn't hot.

On the other issues you just raised, what is your rear axle weight?

It does have a full fan shroud. It doesn’t actually overheat, it idles below 200° but it will peg 230° climbing a hill easy. It will get to 220° on smaller rolling hills. I don’t hear the fan fully engage until 225°, where the Hayden clutch will engage at 210° Which will help prevent everything from heat soaking and ever getting up that high. I know those temps are technically ok, and it’s doing exactly what it’s designed to do when it gets to max temp and the fan engages and cools it back down, but it’s a little nerve wracking and if I can keep it running lower than that I’d much prefer it. It’s a common swap among Duramax owners that tow heavy.

My rear axle is rated for 13,500lbs. The truck weighs 11k with most of that being on the front axle. With the my current camper and Jeep I just sold, the rear axle scaled at under 11k.
 
I could not tell from pics but does your trans run through the radiator before going to the external cooler? Is so, maybe take it out of the radiator and run it to an external only. On my 3500 gasser work truck I had my trans rebuilt and the builder said to do this and to use a Hayden 671, which I did and I had bad trans overheating for a while until I installed a Tru Cool 40K LPD47391 trans cooler and it dropped my trans temps 30-40 degrees. I'm sure your trans makes a lot of heat so getting it out of the radiator may help.
And on my Dmax pickup the engine temp is always 210 but it never gets higher, I'd like to see it lower but everything is stock so I haven't touched it.
 
Nooo. Don't take it out of the radiator on an Allison. If anything just add a larger external cooler. Not only will it help trans temps, but it'll also help pull some heat out of the coolant. It helps warm it up (definitely important in a pickup so the converter will lock up, trans fluid temp has to hit 100 degrees before it locks) and also regulates it. It doesn't make much heat once the converter locks anyway.

Also, the factory gauge won't go above "210" (on a pickup) even when the coolant temps get in to the 220-225 area because it's still considered normal operating temp. They're designed to give you a false sense of security :D My actual coolant temp is 186 when the dash needle it pointed straight up at 210 like normal. It's kind of a....suggestion 😂

FWIW, with Hayden 2886 fan clutch, a larger PPE trans cooler, and a 2020 oil cooler, I've never seen coolant temps over 199 degrees as read by a CTS monitor through the ECM. Gross weight was around 23k and pulling uphill in WV. I know the MegaHauler is different, but you're definitely on the right track.

Running along empty, my coolant temps are 186-190. Stock trans temps were always 170-ish after the cooler. I'm sure this newly built one will be a little higher as it runs noticeably higher line pressure and will hold full line pressure even when the converter locks. Should still be 180-185, I believe. We shall see!
 
I don’t plan on messing with the trans cooler in any way. It’s never once even hinted at getting hot. As mentioned above, the truck itself is not actually getting hot, it’s all working as normal. The HD fan clutch is just a way of making it run cooler for HD use.
 
Nooo. Don't take it out of the radiator on an Allison. If anything just add a larger external cooler. Not only will it help trans temps, but it'll also help pull some heat out of the coolant. It helps warm it up (definitely important in a pickup so the converter will lock up, trans fluid temp has to hit 100 degrees before it locks) and also regulates it. It doesn't make much heat once the converter locks anyway.

Also, the factory gauge won't go above "210" (on a pickup) even when the coolant temps get in to the 220-225 area because it's still considered normal operating temp. They're designed to give you a false sense of security :D My actual coolant temp is 186 when the dash needle it pointed straight up at 210 like normal. It's kind of a....suggestion 😂

FWIW, with Hayden 2886 fan clutch, a larger PPE trans cooler, and a 2020 oil cooler, I've never seen coolant temps over 199 degrees as read by a CTS monitor through the ECM. Gross weight was around 23k and pulling uphill in WV. I know the MegaHauler is different, but you're definitely on the right track.

Running along empty, my coolant temps are 186-190. Stock trans temps were always 170-ish after the cooler. I'm sure this newly built one will be a little higher as it runs noticeably higher line pressure and will hold full line pressure even when the converter locks. Should still be 180-185, I believe. We shall see!

^don't do this, the Allison runs significantly hotter than a 4l80e/6l80e. A standalone trans cooler won't be sufficient for cooling the Allison.

Shoulda known @Croatan_Kid would beat me and add wayy more info :laughing:
Ok, I hesitated before posting since I was talkling 4L80E and 6.0 but I went ahead and did it! lol Carry on fellas!
 
along with the underbody boxes
Did you go with the boxes @jeepinmatt recommended?

Under/on bed boxes is coming to the top of my towrig list! I'm tired of the backseat/floorboard area crammed full of stuff that shouldn't be inside and crap in the bed that needs to be protected from the weather...

I found a set at RuralKing (Delta? or ?) in the "scratch & dent" section that were noticeably better constructed than the TSC/NH/other boxes, but waited too long to pounce :(
 
Did you go with the boxes @jeepinmatt recommended?

Under/on bed boxes is coming to the top of my towrig list! I'm tired of the backseat/floorboard area crammed full of stuff that shouldn't be inside and crap in the bed that needs to be protected from the weather...

I found a set at RuralKing (Delta? or ?) in the "scratch & dent" section that were noticeably better constructed than the TSC/NH/other boxes, but waited too long to pounce :(

I have not bought them yet but that’s what I intend to go with. Just need to find time to drive down to Charlotte.
 
I have not bought them yet but that’s what I intend to go with. Just need to find time to drive down to Charlotte.
When you do, you better make it near lunchtime. That place is 5 minutes from a dang good Salvadoran restaurant (that is also 5 minutes from me) and we will be the only native english speakers there.
 
When you do, you better make it near lunchtime. That place is 5 minutes from a dang good Salvadoran restaurant (that is also 5 minutes from me) and we will be the only native english speakers there.

So you’re saying you wanna meet for lunch?
 
I better get invited to this impromptu meetup.
We will Rock paper scissors for expense account selection

:huggy:
 
Most of my exhaust parts are in. The rest are due next week. Just some hangers and clamps, and some 4” pipe with a turn down.
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I went to Alliance Hose & Fitting today and they hooked me up with an adapter to the new air brake, and the air line needed to adapt my new air compressor to the tank. I hooked it up today but I have an air leak somewhere. I’m gonna mess with it more this weekend and find the leak. My house is being shown for open house today, and we have another showing tomorrow.

If all else fails it may be easier to rewire and plumb it in a way that it skips the tank and solenoid and the compressor itself comes on as the brake is applied and that air goes right to the PAC Brake.
 
Hope the house sells for the right price. Do you have the new RV yet?
 
Got the exhaust done today. Very happy with the muffler @shawn recommended. It’s not nearly as loud as it was straight piped but still has a nice rumble to it.

Just need to get the air compressor mounted and plumbed in. I have 5’ of 4” exhaust leftover, I may extend it back further later. My trip to Ivy Branch soon will determine that.
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wife came outside and said “you know it’s raining right?” as if I didn’t know. I was soaked from head to toe. Soon as I got balls deep into replacing the AC condenser it’s started raining but I just stayed with it.

I don’t know if I ever explained what was wrong with the AC. I thought it was the schrader valve leaking so I replaced it, which was in fact leaking a little. But I quickly discovered a hole in the condenser when we charged it up. It turns out it was my fault from when I had the intercooler out for cleaning. When I put it back together a trans cooler line was touching the condenser and it slowly rubbed a hole into it. It didn’t show itself when we put it under vacuum cause it pulled it against itself and the pump overpowered the leak. So now that’s replaced and ready Be recharged.
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