I'll throw in my $0.02 as well....

All mods have risks, so in that regard your friends are right. A 10k lb trailer should be well within the capabilities of your 4R100 especially since you have added a nice supplemental cooler. I presume one of your gauges is a trans temp gauge, correct?

Do you have an early or late 99 engine? Have you taken your truck and trailer to the scales and had them both weighed? 10k lbs sounds awful light for a toyhauler so it's really helpful to know for sure what your loaded weight is before we talk about tuners.

Since you are concerned about your transmission specifically....how frequently have you been changing the fluid? Have you ever submitted a fluid sample to the lab for analysis? If not, now is a great time to do that before you add a tuner. Have you owned your truck since new?

I can 100% sympathize with your question because I've been there myself. In a way you are lucky because you have a much larger knowledge base now than was available 5 years ago so I think you are wise to ask these sorts of questions. You will just have to realize that no one will be able to guarantee you anything....best we can do is give you our own thoughts and personal experiences and hopefully you will find some of the information useful.


If you are reading this far then I presume you might be interested in my personal experience...
I towed a 12k lb toy hauler fifth wheel around for about 3 years in stock tune without any issues. This was before I knew anything about protecting my 4R100 or having the sense to add a supplemental transmission cooler. I did take my truck to the dealer about every 60k miles and paid for a transmission fluid flush but I don't really know what they did exactly. My guess is they just drained the pan, changed the filter and filled with new fluid to bring it back up to proper level. During the 120k service, the dealer told me my transmission was healthy and doesn't appear to have any issues. (take that with a grain of salt...)

About 13k miles later I upgraded to a larger and heavier fifth wheel that weighs 16,500 lbs. Dry weight on the sticker was 11,500 lbs but actual loaded weight was substantially more.

About 7k miles later my transmission died. I think the heavier trailer killed it. To compound matters, I had recently towed the trailer to the lake through some very steep canyon roads which most certainly overheated the fluid.

About 13 k miles later I added a Bully Dog Power Pup programmer using the 50 hp Tow setting and haven't had any problems to speak of. I towed this way for an additional 125k miles and have my trans fluid sampled on a regular basis and it's still strong and healthy. However, I upgraded the trans when it was overhauled and added a supplemental cooler and gauges so I have no idea if a stock remanufactured trans would have survived.

I recently have switched to custom tunes and decided to go with PHP. I spoke with about 2 dozen 7.3 owners who had custom tunes and gathered as much info as possible and eventually chose a brand of tuner based on the recommendations, concerns and a handful of test drives that I was lucky enough to participate with. In my case, I narrowed my choices down to DP and PHP. From what I can tell, DP uses a proprietary type of chip that only works with their tunes where PHP uses something called the TS style chip and can accept tunes from a variety of tuners. DP offers a decel tune where PHP does not, this is a pretty big deal if you tow heavy because using the exhaust back pressure valve as an engine brake is a fantastic feature in my opinion....but I probably wouldn't recommend doing that unless you have some way of increasing line pressure to ensure the coast clutch isn't slipping. I am not certain, but I believe a modified valve body and proper DP tunes will work well with the decel tune but you should confirm with alternate sources.

In my case, I already had a heavily modified transmission and manually wired switches for TC lock and EBPV so I really don't need the 'decel' feature that DP offers so it was just down to which tuner was best for me. From what I read on this forum and via personal discussions, almost all owners of DP tuners strongly recommend that you perform supporting mods such as larger exhaust and 6637 filter and also get gauges to watch the EGTs so they don't get too high. Reading between the lines tells me that DP tunes might possibly be a little bit too aggressive for what I am looking for if you have to do all that in order to run their tunes. I also have been lucky enough to test drive two DP tuned trucks and they both were quite impressive and powerful, one was heavily modified (injectors, hpop, turbo etc) and I did notice that the transmission fluid temp did climb fairly quickly after a few WOT runs so that caused me to consider PHP a little more than DP.

I ended up choosing PHP because I am still running my stock intake and exhaust and they have a tow tune for the weight I am towing. When I was shopping for tunes the highest weight tow tune that DP offered was 14k lbs. I just checked their website and it looks like they now offer heavier tow tunes so you have more options than I had at the time I was shopping.

I think you want to try and get custom tunes if possible. The one size fits all brands such as Bully Dog, SuperChips etc are moderately effective but they cost just as much so you might as well get something that is custom programmed for your particular truck by a tuner that has been doing this for a while. Plus you get the benefit of switching tunes on the fly so that is worth the price right there. I would expect that custom tunes now a days are highly refined because places like DP and PHP have been doing this for a while and they have a ton of experience. I recommend you talk to as many people as you can that are using custom tunes and that will help you decide what is best for your situation.

I hope this info helps and doesn't cause more confusion.

Happy Towing!

 

Impossible to tell scientifically...I know few want to hear that, but unless the chip/tuner/whatever stored a "I fried this or that component" on a memory chip, you can't tell if the failure was due to the chip/tuner/whatever or that component was going to fail anyway.

 

Thanks for the well informed suggestions. I have owned this truck since it had 23k on it now it about 123k. It is a early 99. I replaced the trans fluid when I first got it and checking my records just about every 27 to 30k miles since then. I have had the same outfit do the flush as I watch. Trans fluid always looks good but I have never had it tested. Since I do tow, I have no problem about spending the money to make sure the tranny is fresh.

I was interested in the Decel tune offerd by DP. But I will have to get more info because I dont want to modify the trans at this time. And If I have to modify the trans to add a tuner I will leave the truck stock.

My primary concern is the transmission which is why I put on the 6.0 cooler. With gauges I am constantly aware of my trans temps.

Just for info let me put the weights of my truck and trailer down here.

Truck and Trailer weight
Trailer
Dry 8400
Gross 14600

Truck without trailer but has fiberglass canopy

Front 4250lbs
Rear 3100lbs

Truck Loaded with TH and WDH
Front 4050lbs
Rear 5500lbs

Trailer connected to truck and fully loaded with 80 gallons of water and cargo. (I don't tow with this much water but wanted a fully loaded trailer weight just in case)

Toy Hauler Both Axles 10,650lbs

 

Looking at the weight figures you posted, I'd say your trailer weighs about 13,000 lbs. 10,650 plus the 2400 tongue weight. Also looks like you might want to look at your WDH set up because it may not be adjusted correctly, or maybe think about putting more air in the rear bags. You lost 200 lbs of weight over the front axle with the trailer connected. With the WDH, the front axle weight should remain about the same.

The e99 engine has slightly smaller injectors, hpop and turbo so you will be a little limited on the amount of power a tuner can provide. However, that might actually be a good thing because it doesn't sound like you are looking for gobs of power. It sounds like you are interested in some additional power while towing and the exhaust brake feature. I think you should call the folks at DP and talk to them about your needs. Knowing your exact weights is a plus and they can probably tell you if they are able to up the line pressure in the transmission enough to use the decel tune without any issues. Since you have a transmission temp gauge you will probably be able to tell if the clutch is slipping because the fluid temp will climb while using the decel tune.

Another plus you have with the e99 is that with smaller injectors and turbo, you aren't in much danger of having high EGTs so you won't need to get a larger exhaust system.

Like Neal said, there is really no way to know for sure. Sometimes things just happen and we never know the real reason why. You can send a trans fluid sample for analysis and that might alert you to a potential problem brewing inside but it might also be normal and then you are still left wondering. You can do what I did and wait until the trans fails, get it overhauled and beefed up, then upgrade the PCM programming but who knows when that will happen? (if ever)

If in doubt, then just keep it stock, watch your temps and you should be good for many years to come. Even in stock form these trucks are strong pullers and the 7.3 responds well when it gets a regular work out pulling around a trailer like you have.

 

Thanks for that info..... I may have to go down to the Towing forum but I have put about as much pressure on the WDH as I dare... It is a 14k Rated WDH and the hitch on the truck is rated at 16k. Truck is level when towing. When loaded and WDH there is only about 1/2 inch difference (lower) in the rear with 50lbs in air bags. No measurable difference in the front. I also use two friction type sway control bars.

 

If the truck is level when towing then I'd say you are good. A good quality brake controller will have a slight delay anyway so that should be enough time for the weight to transfer to the front axle and maximize the effect of your braking system.

Sounds like you are doing everything you can to tow safely and enjoy stress free trips.

 

I put a DP-Tuner in the '99 I had, loved it but it is a stick shift. Nephew has it now. plan on putting one in the '01 I have now when funds are available.
As far as mechanical failures, no.

 

LOL...

Love it when a guy says you will not be in danger of having high EGT's...

Here is a piston out of my E99 with just a superchips, intake and exhaust...



So before you go saying there is no worries... Might put some experance behind your comments.

 

I pull various things, but 1 regular item is my 23ft Hydra Sport Vector. @around 7K#'s I can pull out on the main road and peg 1200* on my pyro in a matter of seconds.

Chips are good, but monitoring and right foot control is what keeps her alive.

 

Joe, is the damage seen on that piston caused by high EGTs?

In my case I am speaking from experience but it is always good to get other opinions as well. I never had any problems with high EGTs the whole time that I was using the Bully Dog or Super Chips on my truck, even when towing. The max temps have been around 1300 but it didn't stay that high very long. I figure that e99 injectors flow less fuel so they must also produce less EGTs. Does that sound reasonable?

So far the PHP chip has also been good with EGTs. The hottest tune I have is 80 Performance and I have to stand on it for about 10 seconds before the EGTs will reach 1300 (unloaded). I haven't towed with it yet so that will be the real test for me, however I obviously wouldn't be using the 80 P tune...

Perhaps the difference between mine and your experiences are the level of tunes chosen? I have only used the tow tunes with BD or SC programmers and so far the 60 daily driver or 80 performance tune on the PHP. If you are experiencing piston damage then it would be good to know what setting you were using so we can learn from your experience.

 

What setting are you using on the BDPP? 50 tow?

 

on 80 performance. I know what your gonna say next, that's why I baby my truck when towing. I am resposible enough to what my gauges and keep her unloaded when towing.

 

Yep Greg that what prolonged running with high egt's looks like! Remember that most aluminum alloy will hit eutectic at around 1425*F ^so when an engine is pushing exhaust out at 1400*+ it's a matter of seconds before the thinnest crossection of the piston becomes plastic and total failure is then unavoidable! Look at the wavy section of the piston left of the broken ring land! That entire area was molten, meaning at or past it's eutectic point! Know your EGT's under all conditions with all tunes if a tune spikes 1400*or higher dump it or add more air!
Jim & fat Monty

 

Good info. I never towed with any other setting than 50 tow so that explains why my readings are different. I bet you are going to like the ability to change tunes on the fly when you get your DP installed.

 

What puzzles me is the damage on that piston is on top of the landing near the edge ring groove. Isn't the combustion event in the bowl for the most part? I wonder if the other 7 pistons had the exact same damage? To me that looks more like a possible issue with debris in the cylinder or maybe excessively advanced timing but I haven't had much opportunity to examime diesel engine carnage. Nitro yes...diesel not so much.