I second Nate and Todd. I have towed heavy trailers most of my driving life and the OBS is just a different animal. My gears are 4:10s so I can't weigh in there, but it seems like it would make a big difference. When I have pulled steep grades towing my trailer, keeping it up around 25-2600 kept the EGTs manageable and my speed up...and that's 10,500!! So don't be too hard on her. Just keep modding as you go. It'll get better. Travis had to help me a little last summer cuz I was so used to pulling with a Cummins. You wouldn't think it, but two ENTIRELY different towing experiences.

 

I hate to say it but I really think either 4.10 swap or more powa are in order.

His truck has almost 400k also. It seems to run fine ttight tho.

The oil getting hot worries me most tho. Am I crazy? That's dang hot.

I'm thinking the gear change would let him get into the operating range better and thus pull at a higher speed. He was really struggling the whole 14-15 hr trip.
But when he pulled my box down it was not so much an issue so what gives??? Idk

Boost leaks maybe? We know his bellowed up pipes are sealed tight from what I could see.

Even in stock tune it was no bueno. He tried the chip to see of extra power could help speed and thus better rpm range. It just shouldn't be such an issue I would not have thought.

 

First off let me say thank you for all the responses. This was exactly what I was wanting, was to generate some discussion!

I wondered about the miles on the motor. Its at almost 380K. I have to keep telling myself that nothing on this truck is new, I have allowed myself to get into a mindset that miles don't matter (or shouldn't matter) but you are right, it deserves consideration.

I have no history on injectors, they could be originals for all I know. I did do a compression test on the one bank, I think my highest was 340 and lowest was 300, which I deemed acceptable.

I also realize that the 3.55 gears arent doing me any favors. I may have a gear set to swap in. The rear axle is going to need some attention at some point, as the LS clutches are coming apart.

And yes you do have a big challenge ahead! I'm curious to see how Blue Ox does. I'll bet you will be fine, it won't be fast, but it will get you there!

Yeah the whole time I saw that I was thinking of your thread, trying to remember what numbers were considered too hot, It was more a err on the side of caution. I may be swapping that T-Stat out here soon.

I'll be paying closer attention to that thread now. I have seen in on here and reading here and there, but I may go back and look it over.

I have the same exhaust set up, 3in DP into 4in exhaust.

Gearing down helps initially, but ultimately I found just slows the inevitable.


Yeah I guess I just didn't think it would be that bad, I knew it would be different, but I was hoping for low teens. Believe me I wasn't afraid to rev it up, it spent a lot of time at 2500-3000 RPM. But I was still driving by the EGT Gauge.

I'm consider removing the chip and seeing what happens. While its in "Stock" I still think it is different than no chip.

I can't complain, the truck has done everything I have ever asked it to do. I'm just beginning to wonder if the motor isn't geting "tired" I need to do a compression test on the other side and see what I've got.

Yeah I just need to figure out what I want to do. I think going to 4.10 will help, then starting the vicious cycle of bigger sticks, turbo, hpop will pry begin after that.

 

Or Both...lol

I know it was pry at least that hot or hotter at one point on the way back to your house.

I still think your box was more aerodynamic than mine is, I really think that skin on the bottom helps it cut through the wind better, where mine doesn't have that, its also taller than the HR.

IDK, I'm just spitting ideas...lol.

 

I'm not a believer in gearing being the be-all-end-all solution that a lot of guys tend to think it is. What it does is that it effectively moves around the power band as it relates to your ground speed. It does this by limiting the upper end so that it compresses the power into a narrower band. So tell me this. Theoretically speaking, what's the difference between my truck spinning 2500 RPM at 60 in 4th gear (direct drive) and a truck with 4.65 gears spinning effectively the same speed in OD? Not much, in my opinion. Yes, you gain the benefit of having the narrower ratios between gears, but all that aside, you're still spinning the same engine speed as it relates to ground speed. Now if all you do with the truck is tow, then heck yeah, put 4.10s in it. But if you drive it empty a good portion of the time, run a conservatively sized tire (both of which you seem to do) then I don't know that going to 4.10s is going to be the trick. I like my 3.55s for the way I use my truck. It gets driven empty a decent part of the time and man, it just loves to cruise at 70 MPH with the gearing I have now. That makes it really nice for road trips. Now if all I did with it was tow trailers, then yeah, I'd want 4.10 gears because I realize that 70 MPH is on the upper end of the speed range that the truck will be useful at, so I would want that to be the upper end of its effective power band. As it is, it is just as happy as a lark at that speed, it's not straining.

I would concur that a compression test on the other bank wouldn't be a bad idea, but unless you find something that is really out of the ordinary, I don't think engine wear is your issue. Injectors could be partly to blame, but the only way to know for sure is to swap them out. If you're going to do that, then I think stage 1's are the way to go. Then it will have the power you want, but the EGTs are still going to be a battle. Then the build is on...HPOP, IC, Trans, turbo, lol. Where do you quit?

I guess I'd do a complete compression test, and a boost leak test and see what you come up with. I'm not sure what else to suggest, honestly.

 

The more I think about it, if your compression is good, and you're not leaking boost I think it's your injectors.

What does the truck smell like at idle? Does it haze at all? Does the smell burn your eyes and nose? If you're not getting good atomization because of worn out injectors you're not going to be burning cleanly, making all the power you need, and your EGTs will be high. Have you seen Stinky's video on atomization?


If you're "squirting" diesel instead of "spraying" or "misting" it, you're not making clean power and the result will be exhaust that burns your eyes and nose, slight haze from the exhaust at idle (even when at operating temperature), diminished fuel efficiency, loss of performance and (drumroll please.....) elevated EGTs. The higher EGTs are a result of the fact that the diesel isn't atomized properly so it takes longer for it to burn, which means that it may still be burning partially when the exhaust valves open and it gets pushed out of the combustion chamber. Does that make sense to anybody else? It makes sense in the tangled ball of yarn between my ears....

 

Yes I believe injectors are partially to blame. And yes I get the haze burning the eyes, especially when cold. not really when warm, But wouldn't it smoke under load? I really wasn't seeing much smoke.

Either way I think I should start with injectors.

And I'm not 100% sold on 4.10 being the fix all either. I really don't want to loose that cruise ability unloaded on a long trip. I think your right, your just moving the power to anther spot.

Edit: Tried repping you for the vid, but I'm in jail...lol

 

I think Nate brings several good points. He also does not drive it in the winter so it is not salt covered so a third of the year is out.now also he has a fleet of vehicles lol so gas getters are there. One other point is his d60 swap front diff has 4.10.....and his rear needs attention very badly.
With that said....I won't switch to 4.10 in mine. I just can't loose my highway drivability unloaded.my combo at 70 like yours is not an issue to tow. Below that I'm hosed.

I'm just not sure he is really wanting to go down the slippery slope of the list of mods to make a high perf towing rig?its an all or nothing IMO and wow is it expensive even on my diy budjet...

Test and go from there!

 

I'd do a compression test and boost leak test, but I'd be giving those injectors the "ol hairy eyeball" given what I've been through with my truck.

I don't know that you would really see that much smoke under throttle. When the boost is up there and you're moving down the road, it is hard to see much smoke with stock injectors. If I bog mine and turn up the chip I can lay down a good haze but that's harder to do with the "slush-o-matic" than it is with a ZF5 because the RPMs will come up faster with the TC unlocked. You're not so much spraying so much fuel that it can't burn as you are spraying it such that is doesn't burn as quickly and cleanly as possible. This is all just my $.02 though...

 

If anyone had a set of know good ones I could swap, I have a set of cores. Aaron do you still have your set? Or do you think without new ones I would be just peeing in the wind? lol.

 

I found this thread very interesting, as it sounds identical to my issues I had a while back. Exact same issues with EGTs. I have never really modded 7.3s and it was quite a learning curve. I had my truck setup exactly like yours, except with a 6.0 IC and 3” plenums on the motor. That being said I had a hard time keeping the truck under 1250 towing any mountain pass with 4:10s and a ZF. I was towing a 20’ enclosed trailer filled with bike stuff and probably wasn’t over 8000 lbs. Elevation was anywhere from 6000-11,000ft. To say I could get it that hot in a stock tune with a DP chip was pretty frustrating, especially considering I had an intercooler. The rest of the tunes were useless, they actually blew a chit ton of smoke and produced less boost.

I tried everything in the book on here, new up pipe donuts, boost leak checked to 20 psi(Never boosted higher), put in a billet wheel, reburned chip, rebuilt turbo with 360* thrust, deleted the EBPV, deleted pedestal, exhaust, t500, filter and so on… Did it change, yes, but not much. Was it worth the thousands of dollars I just dropped, hell no. I was still very pissed. The biggest change was when I threw water injection on the truck. I did not run methanol, but straight water. Literally burned ½ gallon of water for every gallon of diesel. This in itself let me tow how I wanted in a stock tune, dropped temps 100-150 degrees, but still was just a band aid for the big problem. I typical sat right around 14-15 psi on stock sticks, with water I could hit 18, so a 20% jump is a lot, and really makes a difference when you are in it. Still could not use my tow tune or anything else from DP though… so there is 500$ sitting idle.
I then threw stage 1s in there due to blown orings and a couple sticking injectors. Even on a stock tune I could hit 1250 ish on a good pull with water. So we are back where we started. Boost went up a bit too, but I was now towing 17k lb 40’ trailer. That being said I average near the same mpgs towing either trailer. Towing the tag pull was like towing a darn wind sail…in heavy winds it was unreal, the goose was night and day different. Most time I actually averaged better mpgs on the flats with the goose even at 17k… mountains were a different story but that’s to be expected with twice the weight behind you.

All that being said I finally tossed a s366 on there. Good god what a difference in temps. I can now run under 1200 without water in a stock tune, with water we are in the high 900s. That all being said with stage 1s in a stock tune, I honestly think it’s a must to get the truck live tuned or have a bigger charger on there. Period. I am still unable to run in anything besides stock on my chip, but that’s because the tuning is still all effed up. I have a fps up in the 4.5s at 2000 rpm…most other tunes I have seen that to be in the 1.8-2.1 range… To be honest it’s all over the place. I’m trading it in for an F6 and better get the issue resolved the third go around. I do not think the reburn was done for bigger injectors…it will blow black like a pulling truck on spool up. It’s embarrassing.
My story is different as most driving is 6500 ft and above up in the mountains here. It a completely different ball game compared to 2000’ or lower. The truck runs nearly 100 to 150* degrees cooler at lower elevations, and runs sooo much better. It’s simply air density.
Lastly I do not think a gear change will solve your issue at all. Help? Yes, but it won’t solve the problem. It looks like you have 33/35s on there with 3:55s. That’s a lot of meat to spin. I wish they made a 9.50” wide 35” tire, I think it would be perfect for 4:10s even towing, 3:55s.

Through all those heat issues I never saw my oil temperature near that! Not even close!
Hopefully this helps…sorry for the scatterbrained thoughts

 

You know me way too well brother...lol. This is exatly where I'm at.

Yeah I noticed when we were finally out, on the flat, it was better, but still not ideal. This is the biggest trip I do a year, but I would still like to be able to pull with confidence a few hours away (like into WI, IN, or MI).

I noticed what would drive the EOT up was running hard in 3rd, EGT's were still in the neighborhood of 1200, sometimes more, though I tried to stay away, there were a couple of stretches where it wasn't a choice. I felt guilty running her that hard, but had to try and keep moving.

This thread has given me several things to consider, and I'm overwhelemd by all the response it has generated. This is why I love this place. At least I'm not alone...lol.

 

Don't you have a certain guys compression tester? Lol.

Check compression, boost leaks and then send the sticks to Jim if everything checks out. You're more than likely going to need rebuilt ones. Then Save your pennies for air, IC and T500. If you keep it to those mods, the price isn't terrible. Expensive yes, but not the way Aaron went. Lol. I wouldn't be worried to tow your trailer with 1's at all. Hell I pull heavy all the time with my 180/80's!

On edit. Deals are out there on these parts. I have gotten them before. You just gotta be ready and keep your ears open. Lol. Gabe, you ready to sell that 366 yet!!?? LMAO.

 

Haha yes I do. lol.

I'm wondering if I should lay off the driving untill I get that rear end sorted out, that is a whole other mess there.

Basically I pulled the inspection plug for a fluid check, and got several large chunks (not the super fine metal slurry) out of the magnet on the plug. Freaked out, I changed the fluid, but it still isn't right, Aaron seemed to think the LS unit is worn out and coming apart (supprise supprise knocking on the door of 400K)

So I think his point was if it was going to need attention anyway, then swap. I have a gear set out of an 88, but like I said I would like to keep 3.55s just for the sake of cruise speed. That is a delimea I'll have to sort out later.

 

Yea I have the cores still.I doubt bill would care if you borrowed them for your deal ...