Very "newbie" questions. When towing over the mountain last time, we struggled a bit on the longest parts with high EGT and then speed to keep it down. What is the "best way" to tow?

Trans temp got up to 189F, EGT's up to 1230F but had some difficulty keeping the "sweet spot" of RPMs and power vs the heat and speed.

I downshifted manually to keep the RPMs in the 2500-3000 range and keep the power up, but when the EGTs went up, I let off, which sometimes put me into the "no boost/no power" zone.

At the 2 steepest and longest points, I just had to give up, down shift the auto to the next gear and crawl up the hill to keep the rpms and heat down.

Maybe I'm doing it wrong on these diesels?

Max temp guidelines I'm using.

1. Trans temp: 250F for 30 mins. Haven't broken or touched 200F yet, so seems good with the 6.0 cooler.

2. EGT: 1200F to throttle back not to hit 1250F danger point. But now I read that 1250F is okay for short periods? If I reset my max guideline to 1240F or 1250F, is that okay? That little bit would have probably been enough to help a great deal on those climbs.

3. Overdrive: Off on steep hills, off on steep descents. Am I heating up or wearing my transmission or torque converter by doing this? I don't have a TC lockup switch that some use for exhaust braking, but have considered it. In those threads, it is mentioned that an unlocked TC builds tons of heat and isn't so good for the TC.

4. Engine braking: Turning O/D off and downshifting to 2nd on steep descents. Good, bad, doesn't matter? I could use brakes more and higher boost on the trailer brake controller downhill. More wear on brakes, but better than transmission/TC - IF that is a problem???

5. RPM: I've tried to keep RPMS higher when it was hot and then not so much strain to cool down. Better to just turn on O/D and lower rpms and give it more time? Is it better for drivetrain and just let the engine catch up? Can I scream uphills at 3000rpm and she'll be fine?

6. EOT: Usually stay in the 215F-220F, but have seen 224F on the hardest parts. How hot is safe and too hot?


We are rolling around 20k-22k combined this upcoming 2500 mile trip next week. I expect to need everything she's got

Thanks

 

Good A.M. to you my friend,
You're once again in my Wheelhouse, so here's my Knowledge..... Your temps are the same that I have dealt with. The rules that I go by are EGT's 1250 Max, no more than 30secs,Trans: 250 Max for 5 mins( mostly cause I never get that high so far) OD off on any incline up or down, and I get a run at those. and if you gotta sit in 3rd or 2nd to maintain 35mph on the hills then Oh well...... My Trans guy, and I've seen Mark K illuminate on this, You keep the Fluid flowing, things will take care of themselves. The Diesels Gods of fate will take care of the rest.


And I've got Decel on my Tuner, and It Really helps on the Brakes.....

 

And the whole OD thing,....If you leave it on all the time, you'll notice it's gonna "Hunt" all the time up and down hills...and the Flats for that matter. Towing all that weight only makes it worse. all that shifting can't be good.

 

You're perfectly fine there.

You're right, 1250 in short short bursts is ok, but when towing up mountain passes try not to get it up there if possible because you aren't coming down from those temps very quickly. Keep it around 1200 or less as much as you can.

Whatever keeps the transmission in 1 gear the longest, do that. Hunting for gears constantly while towing is what creates a lot of heat in the trans. Same thing with locking/unlocking the TC all the time.

You'll be fine, I did that all the time on my truck. Throw in 2nd on long slow steep hills with a load and it holds speed pretty good. A slow speed, so I only used this on the mountain back roads and not the interstate.

You can run all day at 3,000 RPM and the motor will be plenty happy.

Higher RPM's for climbing with heavy loads will help keep the turbo spinning, airflow moving, and EGT's in check. If you are lugging the engine pulling a load uphill, you'll see EGT's spiking quicker.

You're perfectly fine there. It's quite difficult to get EOT up too high on these trucks, unless you actually have some problem with the engine or cooling system.

The issue you're fighting is in your sig.... the larger tires.

When I first moved to Colorado with my old truck I was running 35" tires on stock gears. Struggled like you to keep EGT's down when towing. In the Carolinas in the Appalachians towing wasn't a problem. The altitude in the Rockies changed everything. Re-gearing helped out... some. Don't get me wrong it's not a miracle cure, but it made an impact. If that's not an option for you, then you're going to continue to struggle some with EGT control with very heavy loads like that and it will get worse with altitude. It's a matter of RPM's, as larger tires on stock gearing will try and pull you down to engine lugging more often resulting in spiking EGT's. Combine that with a heavy load and thinning air and you see where this is going.

The other thing you didn't mention was what tune you are running in. You have Matt's tunes, but are you using one of his tow tunes or running on a stock calibration?

 

You didn't mention what tune your PCM was in.

I also have GH tunes and I can tell you that if I try to tow the camper in my signature in Daily Driver/Tow I would destroy the engine on the first hill. Now, switch over to Heavy Tow and I cannot get the truck to go past 1150 or so, maybe 1200 unless I am bogging down the engine.

Not sure how the automatic trucks shift manually, but I know when I am climbing a grade 2500-3000 is the sweet spot for my truck to keep the EGT's ~1000 and the speed at 55-65 MPH. Now, if I think that 5th gear will be too high of a gear for the grade I am approaching, I will down shift to 4th just as I start going up the grade. Find the sweet RPM/MPH/EGT spot and maintain speed.

Sometimes 5th gear is just fine and I let cruise control do its thing.

Occasionally I will have to downshift into 3rd in order to keep the RPM's up, but that is only because of traffic or a tight turn that I don't feel comfortable at 55+ MPH.

As Pocket said, these trucks NEED to be in the high RPM band when towing heavy in order to stay healthy. The tune your running has a lot to do with it too.

Daily driving unloaded I am in Daily Drive/Tow. As soon as the camper is hooked up, it goes to Heavy Tow and usually stays there until the camper is home. Just so I don't forget to switch back to Heavy Tow in case the truck is used for driving around.

Hope this makes sense, if not let me know and I will try to elaborate.

P.S. - I have towed heavy 12K lbs for about 15K miles so far with this truck including GA to Seattle and back, GA to Milwaukee and back, etc... This is not a lot of miles compared to some, but certainly enough to get me to where I feel comfortable climbing any grade I am faced with.

 

Thank you all for the great info and feedback

Here's the info I forgot to add.

1. Towing with Gearhead Heavy Tow. Until we hit these couple of big mountains, we were towing through hills (same height but gentler grade) and were much lower on EGTs and did great all around. But now that we hit the limit and have an idea where it is, we started seeing this extra heat.

2. Tires. I haven't updated my sig yet, but just changed to 33.85" tires from the 35's. Still oversized, but a slight improvement. Yes, still 3.73 and not planning the Rockies this trip, though we may be in the Smokies a bit, considering a detour. Yeah, it's harder for sure, but that also works out quite well when not towing as an excellent "travel cruiser yacht" at higher highway speeds. Sort of gotta pick the balance that works for our uses. I'd consider taller gears if needed, but hopefully we'll do okay

3. My boost is still limited to max 26psi Probably a leak or I'm thinking it may be pushing the wastegate open. I have it cranked all the way down, but the spring is 15yrs old, LOL.

4. My rear differential was overfilled. I fixed that last night.

5. Had some extra brake dust on rear passenger wheel the first trip, but cleared up. New calipers all around recently and pads. I just replaced the rear lines with stainless last night. Maybe they were too old and allowing things to hang a bit? Replacing the front later today.

6. I opened my AIS with a 3" hole a few weeks back. My filter minder only maxes about half way now, 1/3 without towing. It was slammed shut even without towing previously.

7. Fresh oil and Power Service gray fuel additive. I didn't have additive every fill-up last trip. The octane boost should help? Should I add a higher concentration, or just a waste?

8. Trans fluid looked, felt, and smelled perfect when I replaced the radiator and trans cooler lines a few weeks ago. I considered changing it because of the long trip, but really no reason to that I can see. I did have to add a little makeup and because I had an initial leak at a fitting.

9. Trans fluid *might* be going out the vent? Drips on the road, but I also had a leaking drain pan bolt that I just fixed with a new gasket, so...? It's a shade low, I'll be topping it off this weekend while driving without towing.

10. Replaced alternator that wasn't regulating properly. Not sure if 12.3v up to 15v would have affected anything driving, though? Wasn't bearing or rotating gear.

11. Fuel pressure is still 80psi-90psi. I did see it drop into the 70's while under max pull up the mountain. I replaced the plunger and seat/gasket with the FPR rebuild kit before our last trip. No difference

12. Fuel leak. I have a topside fuel leak somewhere....not spraying, but probably a Parker fitting. I have some replacements, maybe get on that, too.

I'll DEFINITELY be sure to use Heavy Tow. I turn on Torque Pro before towing, to make sure everything is working properly and looks okay when I start out, so that's part of my routine. I don't usually leave it running all the time, my phone gets hot.

I run Driver side EGT gauge and post filter fuel gauge, though I have the pre-filter installed and have switched between them. Same readings within a psi or so (hoping I had a sensor reading too high problem, but guess not )

Thanks for reading all this!

 

Fuel pressure should not be that high, although it would not change the EGT's or performance you were seeing. When I recently rebuilt by fuel bowl the hard line that goes into the FPR was not in all the way. Even though it did not leak, it was out about 1/4" inch or so and made my FP go to 100 and when I would go WOT it would drop down to ~80.

Normally it was around 60-65, so luckily this was the first line I checked and all has been well since making sure the line was in the way.

I forget, do you have a 38R turbo or just a rebuilt stock like me? As you probably remember my boost peaks ~32 PSI, but I have dialed it back to ~27-28 PSI for heavy towing up grades and to keep things safe.

When boosting to about 27 PSI in 4th gear at 60 MPH towing my 12K lbs camper the EGT's are around 1000 degrees.

I have stock wheels and tires and 3.73 gearing.

 

I read your thread about the line not being inserted fully. Tried that

So far haven't been able to resolve the high fuel pressure issue. I blew through the return line to tank, it was fine, too.

I have a stock GTP38 with SPXTurbo wheel.

I have splitshots and very high FIPW in the tunes (so I'm told)

 

That can be your issue there from my very basic understanding of how that stuff works.

 

Possibly...

You're running splitshots, right?

What is your FIPW in 'Heavy Tow With Wastegate', or in 'Econ-Gus 2013' (which is now 'Gus test John ....' due to the corrected shifting') or 'Street Muscle'?

Mine are easily 3300 and up.

 

Whoo-hoo! Found lots of boost leaks

1. AIH port plug leaked. Added a gasket backer to the oring and used Gasoila on the threads. Boost port on the plug leaked (plug, not used yet), Gasoila on threads.

2. Turbo Red and Green lines and ends all leak some. It popped the line out of the elbow that goes on the wastegate actuator

3. Passenger side lower spider boot leaked. Clamp moved and moved and moved. Ended up using 2 of my original clamps, and one of the new ones in between them as a spacer to hold the upper one in place.

4. Fixed upper spider driver side. Wasn't leaking, but this is the one that popped before. I cut back the foil a bit and put the boot on the outside of the raised ridge

5. Drivers side CAC tube to boot leaked. Removed battery and AIS to access it well and really got it secured.

Tip: When testing for boost leaks, plug the end of the red line into the intake tube where the green line normally is. Makes a loop instead of a leak.

Here are some pics.

This is how I found the clamp it was NOT there when I put it on. I had to fight with it and was certain of it. It slipped.




And my fix:




My modified airbox:





Boost leak test setup:




Lower boot secured:




Big hole where the AIS and battery should be, LOL:




Finishing a late supper and then back out to button her up. Lots of Simple Green all over everything

I am hoping for some noticeable differences, especially with EGT and hopefully power to not lose ground in shift points and such

 

Did You Peek at that Junction Block There under the battery for Rot? (While You Got it Out?)

 

Isn't it booby trapped?

Not this time, but about 2 years ago I did. Looked fine then. Should have checked it again...

My boost is still topping at 25.4psi, maybe just a shade more if I hold it.

It's gotta be the wastegate. I'm going to replace the ends on the blue and green lines when I get a chance.

But that's it for engine work before our trip. Still have to reprogram the key fob (so we can use the alarm) and change the front brake lines.

Rear tires were both spinning as I drove slowly through a muddy part of the yard. Looked like a posi back there

 

FIPW with split shots was my initial thought, what was your #s on your tow tune?

 

What did you use to insulate the CAC tube? I de-foiled mine some years ago but the current me is wishing it was quieter.

Once I saw EGTs of 1350* for approx. a minute, no harm done. Traffic conditions dictated I keep my foot in it.

I'm thinking your boost limit of 25.4 is from the tune (to prevent de-fueling) not a real reading.

Looks like your PS hose is up against the DS shock tower, check it's not rubbing a hole.

As Pocket said altitude has a big impact. One summit I hit was 9600 feet and she was uncomfortably smoky and hot getting over.