Towing With 3.42's

April 22, 2008

Those of you with the 5.3 and 3.42's, what are you're towing experiences. I went from 3.73's to 3.42's on my new truck and the difference to me towing in th mode and in third is'nt all that different. by the way mine is 2006 CCSB Z71 4x4 with no performance mods.

50usilverado · April 22, 2008

depends on what you are towing. my last truck was 4.8 with 3.42 , it was alright but not as great as i was hoping for. i towed a 5400lb trailer, it managed with alot of transmission shifting. This time my 08 has 5.3 with 3.73. hoping it tow's well , fint out may 24 , first weekend of camping.

April 23, 2008

depends on what you are towing. my last truck was 4.8 with 3.42 , it was alright but not as great as i was hoping for. i towed a 5400lb trailer, it managed with alot of transmission shifting. This time my 08 has 5.3 with 3.73. hoping it tow's well , fint out may 24 , first weekend of camping.

Good luck with your camping trip, i can vouch for the 3.73's, my 03 ECSB dill really well.

bbwb · April 23, 2008

Well, I am going through this dilemma right now as well. I have an '06 Sierra with the all aluminum 5.3 (310 hp) Z71 with 3.42 rear end. Last Saturday, I brought my new camper home 24' Outback with 5K dry 6K plus wet. Coming home in tow/haul my truck struggled. I had a slight head wind and every hill was a problem ( had trouble maintaining 50 mph). Hell, fully loaded semi's were passing me on the hill . After much research I was all set to go with the 3.73's but after discussions with other fellow campers, they convinced me to replace the ring/pinion gears with the 4.10's. The added rpms at 70 mph are about 550 over the 3.42's, so decrease in mpg will be about 2 or 3.

The truck could handle the load on the flats or in sheltered areas, but sure was asthmatic on even the slightest hill. One thing to keep in mind is that the truck can handle the weight, but there is significant drag from pulling the billboard behind you.

The truck goes in for the operation on Monday followed by a reprogramming.

bbwb

C & A s Dad · April 23, 2008

You will be pleasantly surprised with what the 4.10s are going to do for you. I am towing a 30 ft 6500 lb camper with the Yuk XL in my sig and it has 4.10s. I would suggest you tow in 3rd gear and you will see RPMs around 2400 at 55. This keeps the little 5.3 right in it's sweet spot where you will not see the bogging issues you see now.

Unless you drive on the interstate a lot when not towing, you are going to find the 4.10s may actually help your MPG.

Let us know how it works out.

bigBP · April 23, 2008

I've got the 5.3L with 3.42s. The most that I tow is a bass boat in the summer and a two place trailer w/ snow-sleds in the winter and I have no problems to speak of using the t/h mode. I haven't really run into a situation yet where the truck hunts between gears constantly. I imagine if you're towing any more than that (travel trailer, etc) the higher gears would be the way to go.

One nice thing about the 3.42 is the non-towing highway mileage. I'm getting around 19 mpg highway right now, on a dead flat stretch with no headwind it can creep up to 20. I've never bothered to check my mileage while towing.

gvbhunt · April 23, 2008

Copied from a post about towing and MPG from earlier...

I will throw my $.02 in on this one. My last truck , 2005 Silverado Extended cab 4x4 5.3L 3.42 gears, I used to tow my lifted Jeep Wrangler on a 20' tandem trailer from Missouri to Colorado to go play in the mountains. I did fine across Kansas, but Kansas is FLAT, and did pretty well until I got past Denver. My mileage across Kansas and the flat of Colorado was between 9 and 11 depending on the wind, but the jeep plus the trailer was probably about 6500Lbs, and the jeep is about as aerodynamic as a refrigerator box which did not help in the slightest since it was way taller than the truck. So my experience with the Missouri to Denver drive was not too bad. I knew it was there but it was not really struggling too much but it did hunt quite a bit between OD and 3rd when it started uphill.

Now in Colorado there were a couple of passes that I drove over and they were crazy enough that the truck was hunting between 1st and 2nd just to try to make it up the hill.

SO...all in all I would have to say that for a normal trailer, even a travel if it is more aerodynamic than an 8' tall jeep on top of a 18" tall trailer, is more than enough. I would recommend starting your long trips late at night or really early in the morning to cut down on wind though.

C & A s Dad · April 23, 2008

I've got the 5.3L with 3.42s. The most that I tow is a bass boat in the summer and a two place trailer w/ snow-sleds in the winter and I have no problems to speak of using the t/h mode. I haven't really run into a situation yet where the truck hunts between gears constantly. I imagine if you're towing any more than that (travel trailer, etc) the higher gears would be the way to go.

One nice thing about the 3.42 is the non-towing highway mileage. I'm getting around 19 mpg highway right now, on a dead flat stretch with no headwind it can creep up to 20. I've never bothered to check my mileage while towing.

There is a real misconception about mileage with 4.10 gears. If your driving does not consist of a lot of high speed (75+ MPH) Interstate driving, the 4.10s can possibly offer better mileage. My Yuk XL is averaging dead on 18 right now with mixed driving but most of it is rural 2 lane roads and some in town. If it is a pure highway run at 65 or less, it will get between 20 and 21. Not bad for a truck this size with 4.10 gears. Also know, my Wife drives very conservatively and I fully realize this contributes greatly to the mileage I am getting.

bigBP · April 24, 2008

Yeah, having the taller gears probably offers better city mileage than the alternative. 90% of my driving is cruising @ 70 mph, my rpms hang just below 2,000.

Ranger · April 24, 2008

If I had the choice I would've gotten 4.10s again, but my 3.73s don't do too bad. I do have to gas it a bit more when going up inclines or ramps but getting 14 mpg mixed city/highway (and lots of lead foot) versus the 8-9 I had with 4.10s is nice.

merace19 · April 30, 2008

my brother and i had identical Company ext cab z71's 5.3 Long wheel base. His had 4.10 and mine 3.73. We put 275k miles on them each with basicly the same style of driving. Our company keep track of the mileage and both were almost the same. Maybe a .18 difference over 275k miles. We drove alot of intown and highway. So the difference is not that much over the LONG haul.

mi.bowtie · April 30, 2008

3.73 is always the best ratio to buy when it is your main driver and towing ocasionaly on weekends and camping trips. It is the best of both worlds. with a 5.3

Daniel T · May 1, 2008

I've got the 5.3L with 3.42s. The most that I tow is a bass boat in the summer and a two place trailer w/ snow-sleds in the winter and I have no problems to speak of using the t/h mode. I haven't really run into a situation yet where the truck hunts between gears constantly. I imagine if you're towing any more than that (travel trailer, etc) the higher gears would be the way to go.

One nice thing about the 3.42 is the non-towing highway mileage. I'm getting around 19 mpg highway right now, on a dead flat stretch with no headwind it can creep up to 20. I've never bothered to check my mileage while towing.

There is a real misconception about mileage with 4.10 gears. If your driving does not consist of a lot of high speed (75+ MPH) Interstate driving, the 4.10s can possibly offer better mileage. My Yuk XL is averaging dead on 18 right now with mixed driving but most of it is rural 2 lane roads and some in town. If it is a pure highway run at 65 or less, it will get between 20 and 21. Not bad for a truck this size with 4.10 gears. Also know, my Wife drives very conservatively and I fully realize this contributes greatly to the mileage I am getting.

Exactly, 2 years ago my wife took the Burb to Reno NV, from San Jose CA. Her avg mileage for the round trip was 18.5mpg. San Jose is just about sea level ~300' by the time you get to Reno from San Jose you have an eleveation of at least 6000' over Donner Pass.

4:10s do not ruin your mileage, not with the newer transmissions with overdrive gearing and lock up torque converters.

I get between 9-11 mpg while pulling my 8,000# RV at ~62mph in 4th gear on flat terrain.

merace19 · May 1, 2008

My point in the other post was to let everyone know we had a documented case study basicly and shows no real difference. If after 275,000 miles is not enough proof then nothing will convince you.

C & A s Dad · May 2, 2008

I've got the 5.3L with 3.42s. The most that I tow is a bass boat in the summer and a two place trailer w/ snow-sleds in the winter and I have no problems to speak of using the t/h mode. I haven't really run into a situation yet where the truck hunts between gears constantly. I imagine if you're towing any more than that (travel trailer, etc) the higher gears would be the way to go.

One nice thing about the 3.42 is the non-towing highway mileage. I'm getting around 19 mpg highway right now, on a dead flat stretch with no headwind it can creep up to 20. I've never bothered to check my mileage while towing.

There is a real misconception about mileage with 4.10 gears. If your driving does not consist of a lot of high speed (75+ MPH) Interstate driving, the 4.10s can possibly offer better mileage. My Yuk XL is averaging dead on 18 right now with mixed driving but most of it is rural 2 lane roads and some in town. If it is a pure highway run at 65 or less, it will get between 20 and 21. Not bad for a truck this size with 4.10 gears. Also know, my Wife drives very conservatively and I fully realize this contributes greatly to the mileage I am getting.

Exactly, 2 years ago my wife took the Burb to Reno NV, from San Jose CA. Her avg mileage for the round trip was 18.5mpg. San Jose is just about sea level ~300' by the time you get to Reno from San Jose you have an eleveation of at least 6000' over Donner Pass.

4:10s do not ruin your mileage, not with the newer transmissions with overdrive gearing and lock up torque converters.

I get between 9-11 mpg while pulling my 8,000# RV at ~62mph in 4th gear on flat terrain.

Daniel, sounds like your 4.10 Burb and my 4.10 Yuk XL are pretty close in MPGs. My average right now is running 18 with mostly rural driving. I have had a few pure hwy runs at speeds less than 65 and it will get between 20 and 21. I checked my mileage this weekend towing my camper and I got just over 10. I was pulling on a 2 lane road at 50 to 55 in 3rd. I rarely have the opportunity (if you want to call it that) to tow on an intersate so I always run in 3rd and keep it under 55.