That "howl" you hear is the same thing I heard with my brand-new '01. Happened for four years, until I went to Mobil 1 (Royal Purple for a few months did NOT change the sound, but Mobil 1 made it go away completely).

The howl is probably just the face of the pinion/ring teeth being slightly rough yet, and over time (years) it will either go away, or stay the exact same way.

There is no bearing that would whine like that when under such a slight load, it would either do it totally on, or totally off.

I WOULD however, ask what kind of fluid they are going to use after the change, and see if Mobil 1 is something they recommend or have available.

 

I remembered your thread about switching to mobile 1 and had already noted that but thank for the tip anyway. The little bit of howl/whine under such limited cirumstances I figured probably wasn't actually hurting a thing however I'm still gonna have them check it over when it's time for a fluid change.

 

Thanks for the reports so far SLE. I want to switch to 4.56's so I always like it when other post their experiences. Waiting to see how it will do towing.

 

I wouldn't worry about a bit of gear noise at part throttle. The pattern may be perfect and some sets are noisier than others.
Been down this road before. And like Krewat said, it can get better or stay the same. I've never seen a new set that is set up properly get worse.

 

Well i sit here at the campground typing this so i made it! Report so far, had 325 miles on when I left with lots of heat cycles. Truck pulled much better. I tried to get a scale ticket but all of the elevators were closed, nevertheless the gcwr should be around 22k lbs. I was able to tow in 3rd no problem and even towed in OD for about 20 miles! I only found 2nd twice on a couple of very large hills. Overall it was a good upgrade, no it's still not.a chipped diesel but it's slot better than it was. At 65mph the truck turns 2200 rpm on OD and right on 3000 in D. For all looking at doing this for towing, my only regret is not doing it sooner! I won't go as far as saying I'm gonna win any races,but it's a good strong pull from 60-70 mph.

 

I have a question, why do you not tow in OD more? I weight about the same as you and pretty much always tow in OD.
I just loaded a premium only tow tune from Mike at 5star and will be towing the rig to the track next weekend.

 

SLE
did you correct the gear ratio for the computer? did you see a differance in mpgs? my truck is similar to yours and I'm on the fence about going to 4.56s. if it will get better fuel "economy" I may have to bite the bullet . thanks

 

You don't have to correct for the gears because the speed is picked up off the ring gear so the axle speed doesn't change. The computer only had to be changed if you change tire size. There is another sensor in the transmission that gives you drive shaft speed and the computer makes its adjustments off of that for shifting and engine control.

Denny

 

Hey SLE, I'm also interested in any change in mileage with the gear swap. I'm mostly looking for a comparison of unladen city/highway mpg numbers, but if you had a good comparison when towing, that would be interesting too.

And, not to question either your method or your commitment, but does anybody ever break in their gears (or their engines for that matter) when they buy a new truck? I'd say most people just roll their new rigs off the lot and drive 'em however they want - no concern about break-in at all. Is it really necessary?

 

I do treat new vehicles nicer for the first few thousand miles. EVERYTHING need to be broken in, and if you want them to last a long time, it helps.

Matter of fact, I look around and see that the ones who do a real break-in seem to have the best long-term luck with their vehicles.

Not too nice, not too much abuse neither.

 

I'm back from vacation for a final update and a little better report. The last one was made typing on my phone and I tried posting 3 or 4 different times but my service was really bad and I didn't actually know if any of them actually got posted, so it was pretty concise.

Overall the 4.56s made towing the train much more enjoyable. No more hunting for gears, no more needing 2nd gear all the darn time, and the wind and hills don't hardly slow me down! Towing at 65 mph is a real reality now and I caught myself at 70 mph a couple of times. On the flat land and very small rolling hills I can tow in OD however most of my trip is through some pretty rolling, hilly area, not mountains or anything, but enough that I really had to use D (3rd) for most of my towing if I didn't want to always be loosing a couple mph on every hill. I found that over the entire trip I only punched it down to 2nd on two very large hills.

The only real downside of the gear change that I could really find is that now when I do need 2nd gear (which is much more rare now) that I'm basically forced down to 55 mph or so due to the rpms being so high. Basically when I'm on a roll at 65 mph and I start up a steep long hill, if I kick it down to 2nd gear to maintain speed, the rpms shoot up to 4,700 or so I and find myself slowing down to about 55 and holding it there as the ol V10 seems happier at 4k rpms than it does closer to 5k rpms, I know many think nothing of running at 5k rpms but I simply perfer not to for more than a short burst here or there. Other than that I have no complaints.

As far as fuel mileage goes I really don't have a good gauge as I did as much idleing around as I did towing so I don't have anything to report. from my eyeball I would say towing mileage is up a bit and my unloaded highway driving is down a little. I put on another 200 miles of unloaded driving before hooking up to come home so I was pretty close in my mileage estimation of having somewhere around 700 miles when I returned, I think I'm at 750 miles or so now on the new gears after the return trip.

Noise wise, nothing has changed, at 70 mph or above and 45 or below you cann't hear anything, between 45-70 there is some whine/howl with the worst being around 60 mph. I do however wonder if I have some issue or it coinincidence becasue at about 60-65 mph I have found I have a vibration. With no load it isn't pronounced at all and is even kind of hard to tell but with the train hooked up there is a noticeable vibration only at that speed otherwise all is good. Years ago I did have to replace the rear U-joint due to a similar issue and I'm acually kind of wonding if it isn't either that u-joint or the front one begining to go. If all checks out when I get the oil changed I'm gonna probably tackle both since they're pretty cheap anyway.

To all looking at this post for there own information please keep in mind that the tires I am running are 285/75/R16 Revo's which pencil out to 32.8" in diameter. I bring this up because it does offset the 4.56 ratio slightly and my overall gear ratio is just slightly deeper than a stock truck with 4.30s and factory sized 265/75/16 tires.

Also a note on the Rpms. at 65 mph in OD the tack appear to be at about 2,200 or so, in D there right around 3,100, and in 2nd at 65 mph it puts me around 4,700-4,800 rpms. Overall this is pretty good for towing however a 5 or 6 speed trans set up correctly with 4.56s or 4.88s really would be nice as a person could have a gear inbetween 2nd and 3rd and agian between 3rd and OD and OD could be stretch out just a little bit more, but that just me dreaming again.

I do think the truck seems more driveable and is certainly lighter on it's feet. I did stand on it from a stop once (right at 515 miles on the OD) and although it didn't light up the tires, it chirped them pretty good on a 90 degree day, I know my Father-In-Law looked at me and said "well, I know the dodge won't do that" (he has mid 2000s Ram 1500)! The only thing I noticed is that with the 5-star 91 octane towing tune installed you just cann't drive like a grandma, not only because it's to fun not to, but more so because if your not accelerating kind of hard the transmission almost lurches you forward when it shifts. With a load or under heavier acceleration it feels great. This could be also partly due to the triple disc converter that was installed as I didn't notice this behavior as much prior to the gear change and trans work.

As far as break-in, I don't know if it's neccessary or not but after sinking $3,700 into the gear change, master rebuilds on both axles, the new shifter stock, and the trans work I certainly wanted to be on the safe side. better safe than sorry!

well, sorry for the unorganized post, I just type things as they came to me but I think I covered all the results for the most part. I'll get a better mileage report out this fall when the camper gets put away and I start hunting as I'll spend more time unloaded and on the highway and I should be able to get a better comparison with real numbers. If anybody has any questions feel free to ask. Thanks for all the help and I'll report back if for nothing else to give an update on the oil changed and the vibration situation.

 

I see it's time to change my signature from "3.73LS" to 4.56LS!

 

I had 4.56s in my old Dodge and had pretty much the same howl as you describe. The wear pattern was spot on and were wearing beautifully - just noisy. The biggest problem I had was engine temperature. It would pull all day long, but couldn't stay cool under load. Rather than spend more on cooling system mods, I traded it for the van.

How did your engine temps react when towing?

 

Great report! "unorganized"? I've seen less organized posts from English majors

I would tend to think that the howl/whine and the driveshaft vibration are NOT related.

However - do you have a two-piece driveshaft with a hanger bearing? Could the bearing be going and that's the source of the noise?

 

There's a possibility it could be the hanger bearing, kind of figured I'd check that anyway when I drop the drive shaft for the u-joints, again assuming the gears aren't the problem.