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Anyone running 4.10 gears for heavy towing?

25K views 60 replies 16 participants last post by  jdwarren 
#1 ·
I have an '07 LBZ crew cab 2wd dually that I tow a 48' race car trailer with living quarters with, usually weighing in the 29,500 range total. I was putting brakes on it this past weekend and saw that the pinion had a little movement in it. Pulled the rear end apart and one of the bolts that holds the spanner locks in had backed out, and the bolt and spanner lock got thrown up into the pinion bearings and the front pinion bearing ended up tearing up the pinion, and wore it down. So there's no interference fit at all. It'll flop around on there. So I need to buy a ring and pinion.


I run Michelin 235/85-16 LTX M/S2 tires which are a little bigger than stock at 31.7", stock being roughly 30.3". I travel all over the place doing 75mph plus or minus a little most of the time.


Can anyone speak from experience on switching to a 4.10 gear in a similar situation? A 4.10 would put me at ~1920rpm at 72mph, where as 3.73s and stock tires would have been ~1830. My fuel mileage ranges around high sevens to low and mid eights most of the time. Most of the routes I travel are hilly, and thinking the gears may help keep it in it's happy power range better. If I'm running 80, it'll definitely hold speed better on hills than it will at 70 with the RPM being higher. Seems to me like a 4.10 would be the right move.


I do run a PPE handheld on economy mode. EGR delete, Pro Fab Y bridge, down pipe, 5" straight exhaust, ARP head studs, etc.
 
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#2 ·
4.10 for DDing more than towing
4.56 for towing more than dding

Ideally 4.30 would be great but finding 4.30 for the front is almost impossible

I run 4.56 with a 32" tire ~2100@70 In 6th
Also recommend a low stall TC. Take advantage of the extra gear multiplication without blowing through the TC in stop n go traffic and starting on hills..,
I run a transtar AX7L ~1700stall for last ~120k miles at ~400rwhp grossing upwards of 36,000lbs. I would also suggest jr kit a s main line pump pressure mod while trans is out.
A7XL was 250+100 core when I did mine last year.. I doubt it would hold max effort stock fuel dmax but that's not what I was after
 
#3 ·
#4 ·
Drive the truck in 5th and see if you like those rpms. Thats almost exactly were 4.30's would put you in 6th.

I have 4.44 and love them but I rarely run over 70mph.
At your weight and speed I think 4.10/4.30 would be great.


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#5 ·
I have a 2WD dually also and want to switch the rear gear out for 4.10s. Truck just seems to work to hard with the bigger loads. Empty it is great with the 3.73 gear. I also have larger than stock tires.
 
#60 ·
With larger tires the final gear ratio is going to be taller than 3.73, possibly down around 3.50 based on the change in the circumference of the new tires. With larger tires on my truck the speedometer shows 60 mph when the truck is actually going 62 mph so not a big change in gearing. It provided a rough guide of how much the tires altered the 3.73 gears, or roughly by 3%. If I had gone to 33-35 inch high tires then 4.11 gears would have been important.
 
#6 ·
Wanted to bump this up and see if anyone else had any input. I am still running 3.73s for now
 
#7 ·
Seems like the Cab and Chassis trucks use the 4:10 gears-- as they are usually heavier and only driven on short trips. You should be fine with the 4:10, as you already changed the final gear ratio higher by adding larger tires. The Allison would like it also.
 
#8 ·
Bump. Still thinking it would be the right move but would like to hear from guys who run 4.10s and do a lot of highway driving.
 
#9 ·
Any new or additional opinions? The truck has 440k on it now, the rear end is getting significantly more whine. It's going to be time soon. I think 4.10 is the way to go.
 
#11 ·
Malibu and Kow covered it some time back.
But,
Stock tires and 3.73 @ 1830...you're running in 6th.

Better performance would be 2050 in 5th, pushing to 2200 on climbs....with stock size tires.
 
#15 ·
Thanks Malibu. All stock here. We are just getting things lined up to start a little travelling program to introduce younger kids and parents to motorcycling. Submitted a design to inTech trailers for a 40' wedge goosneck with living quarters. I'm guessing that we'll be pulling that package 6-8 weekends this year if we get the trailer early enough. Fairly flat here in California, but if we start going to neighboring States or across country with this it will be more.

Since I'm new to the diesel stuff, was just curious about Hook'ems comment about using 5th gear. I've pulled our 20'er several times and haven't had any issues and have tried it with tow setting on and off. Prefer the Towing on as it just seems the engine/tranny seem happier, but am a rookie so asking the basic questions as well.
 
#16 ·
Kaz, sounds like a fun adventure and I wish you luck.

You will need to keep in the back of your mind some weight issues due to your living in CA. While I have never driven a truck out there, I have heard lots of horror stories about CHP, DOT and others pulling folks over and doing spot weighs on their rigs.

The reason that I am passing this along is that if you end up with a 40' goose with living quarters and loaded, you will most likely find that your trailer weight exceeds 10K which will put you into CDL territory if you are operating the rig in a commercial venture. However, if you register it as private or an RV, you should have no issues. Just something to consider.

Back on topic.......
 
#17 ·
Thanks JimmyD. Hoping it will be fun as it won't be a true money maker in the beginning. Breaking even would be fantastic. And yes, I've been doing all my research and trying to establish staying under weight and under max combined length which is why 40' and not 42', 44', ??. Current strategy is to be private/RV, however, there's one brain cell that says just get a Class A non-commercial and be done with it, or just get a commercial and in the future I could perhaps explore new job potentials driving a rig for one of the race teams :)

okay...back on topic!
 
#18 ·
If I'm running with a 40' gooseneck with 15-20k does that still apply.
If I hook on to a trailer, regardless of what it is or if it's loaded or unloaded, the T/H button gets pushed. There's no reason not to, you're not saving anything.
Unlike on a car, On or off, it's different from a car transmission's selecting Tow and what it does on the Allison

As to 5th, or any gear you lock out too, with what ever you're pulling or the grade, the selective shift allows you to control what RPMs you're running, @ what speed.

Most reasonable folks are going to hwy tow their trailer in the 65-72mph zone. And the HD will try and pull that all day in 6th gear at the lowest RPMs, which can be below 1700.

However, if you lock out 5th, that brings your Rs up to 1900-2100, which is the sweet spot for the Dmax. You'll run cooler, lower EGTs, use less fuel and climb the hills easier. And of course if the hill worsens, drop down to 4th and stay up in that higher RPM.
 
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#19 ·
Got it! Just needed to verify you were talking about the sweet spot and the what range rpm's they are.! I did eventually start playing with the gear select switch as I was chasing mpg and watching the instant mpg gauge. Same principals as racing and finding the correct gearing to utilize the engine. Thank you Sir!
 
#21 ·
I think that quote is not done quite correctly 6686L. 'dunno; Anyway you can edit me out of that?
 
#23 ·
He’s a troll, seems to get off on talking down to people and telling us how stupid we are....course then again if he started driving commercially in 1956, assuming he was 18 at the time that makes him 80ish


Just gonna throw this in for our buddy 6686L, I hauled some gravel last weekend and I was about 1000-1200lbs over my dump trailers gvwr.......TWICE. I am still fully alive, no church buses, freight trains, small children, wildlife, pedestrians, livestock, Jeep drivers, crab fisherman, hippies, road side fruit stands, aliens (space or human), or any residents of Arizona were harmed in any way shape or form in my travels :rofl :rof
 
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#24 ·
What 'bout that near-sighted squirrel you scared the shiite' out of?
Mayhem at the wheel, you are sir!
 
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#26 · (Edited by Moderator)
....show me...

Show you ? not possible. Given your incredible brilliance over and above manufacturers & their engineers, waste of your time and mine
 
#27 · (Edited by Moderator)
....show me...

Show you ? not possible. Given your incredible brilliance over and above manufacturers & their engineers, waste of your time and mine

Then why do you try so hard?????
 
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#32 ·
Here's some pics of my junky ass truck
 

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#33 · (Edited)
Here's one of that super dangerous trailer. Funny if you pay attention they are all over. Haven't personally seen one crashed in my travels yet and mine isn't any heavyweight special compared to the rest. People towed these trailers with duallies from the mid 90s that weren't half the truck an 07 LBZ is
 

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#34 ·
This one will have you spun out 6686L
 

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#35 ·
34340....meh, do that all the time.
Same truck...just more chrome.
Not @ 80, but not far below. :howdy
 
#36 ·
That was just a local scrap run when I was clearing out the junkyard before I moved to SC. 45-60mph roads. I've seen people haul a lot heavier than I have with these trucks, but maybe not long distance

This weight ticket was from my last trip down to SC from PA when I moved. It was the race trailer but with lots of extra tools and stuff. If you go by truck GVWR and trailer GVWR I actually wasn't over weight by much
 

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#37 ·
Good to see some folks are serious about maintaining their trucks.

Not clear why one of these guys think I would "spin out". We do get ice on our roads on occasion up here in northern Arizona; I don't care what kind of tires you have...if you are on REAL ice on anything but absolutely level ground, you aren't going anywhere. As for normal winter driving, I stay out of the way in the far right lane, substantially below the normal flow of traffic, so I personally have never spun out in my vehicles.

I remain very unhappy to learn some folks think it is cute to operate a truck and trailer, loaded to max or near it, going at 80 mph, and/or significantly over the speed limit. One need for a panic stop, and/or equipment failure, and you become a menace to yourself as well as the folks around you. Speed limits are not recommendations, nor are they posted for your entertainment.

Well...with this qualification....for example - I-40 from its start in Barstow, California, east to the Calif/Arizona state line. Posted at frequent intervals for us towing, not to go over 55 mph. Given the road conditions, and assuming decent weather & properly maintained equipment, I believe 60-65 mph is at the upper limits of a safe towing speed for our type of vehicle.
 
#44 ·
Spun out meaning shocked, confused, blown away, mad, all up in a tizzy, etc. That is you, sir.

You do realize the speed limit is 75-80mph some places? Get out and see the country and you'll find those places.

Myself personally, I am usually 5-7mph over the speed limit. 10 once in a while if I'm really in a hurry. I don't consider myself to be a fast driver, although I did drive a race car that went 0-200 in 3.7 seconds/660ft so 80mph may be easier for me to process than you
 
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#38 ·
#40 ·
Yeah speed limits are pretty clearly just recommendations.

Proof? Highway Patrol's typical grace is 10-15mph over the limit before they bother to stop you.

A Kansas Highway Patrol came right out and stated one time that their grace was 15mph over.

Of course some municipalities won't give you 15 over, but that's not the point.

And as far as the Left Coast goes, just don't go there. Myself nor any of the other haulers I work with want to go there and only do so if we must. Last time I musted was almost 2 years ago. And I didn't go very far in that time.
 
#43 ·
6686L is still passed out from when he saw your weight slip :grin2:
 
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