Silverado towing advice needed

[mjones12]

Thanks to everyone. Lots of smart guys (and gals) on here with a lot of valuable experience. Thanks so much for sharing your knowledge. And revrnd: let us know when you get your new truck. I'll bet you're going to love it, based on what I think about my new Silverado. I will report back once I tow with it in a couple of weeks. Hope you will do the same when you get the new one.

[revrnd]

I won't be getting mine until late fall after RVing is done for the year. I'll definately post comments next spring.

[mjones12]

Here's an update on the first towing trip with the 2010 Silverado: It pulled the little trailer like a charm. I figure I tow it at only about 4,000 pounds. Going up a long 8 percent grade in the mountains, around 55 mph because it wasn't very curvy, the transmission temp topped out at 228 using the tow/haul mode, which I use exclusively when towing. The temp looks pretty good on the excellent chart provided by Macdaddy. On the downhill return trip, I could feel the truck automatically downshifting after I touched the brakes. Pretty cool.

[imkzru]

@Mjones12

I also have a 2010 Silverado LT Crewcab 5.3l engine with the tow group and was wondering when you go over mountains and the truck downshifts, what RPM are you taching? I just went from Virgina to West TN and going over black mountain on the down hill side the grade is 5% for about 6 or so miles and I found that every time I tapped my brakes the truck downshifted and I was taching between 4.5 and 5k RPM. To be honest I do not like this as it does slow you down, but when the speed limit is 65-70 and you have idiots that want to ride their brakes and truckers that want to ride a little close, this rapid decrease in speed I can see causing and issue. But beside that the RPM's has me concerned. Most V8 engines that I'm familiar with red line at 4k or 5k. My truck does not have any yellow or red line marked on the tachometer, but that high of RPM on a V8 can not be good. Do you know what the red line of this truck is?
On a slightly different note:
I'm also towing a little popup that has a dry weight of about 1200lbs. Your trailer has a dry weight of about 2600lbs. The truck can tow about 10k. From reading your post I'm seeing you are not having any issues towing that size trailer, but towing my little popup I'm finding it searching for gears when going up any size hill. I would love to buy the size trailer you have but I would like to hear from someone who has one and tows their experience?

Lastly this truck has a trailer brake controller, but for the life of me I can not tell how much stopping power I'm putting on to the trailer. Have you found a way to tell or is the amount done automatically?

[revrnd]

Here's the TQ & HP charts for the 5.3L as equipped for Silverados & Sierras.

[jackhartjr]

It is very similar to having a 'jake-brake' on it!
Just leave in in drive and the tow mode on and it will work just fine. We LOVE ours!
I assume you have the Allison trannsmission. My 07' said to replace the trannsmission filter at the first oil change. Keep a spare and an oil filter wrench to change, and several quarts of the tranns fluid just in case it ever gets hit by a rock! It is in a very vunderable place in my opinion. (I now get the tranns fluid at WallMart, hard to find three years ago.

[revrnd]

No Allison w/ the 5.3 L. The Ally is only available w/ the Duramax.

[imkzru]

@Revrnd

Thanks for the .pdf looking at it, it looks like the red line is at 7k RPM. This makes me feel a little better and I guess the downshifting will take getting used to.

Think I will be going to the next RV show and looking around. But I still would like to hear from mjones12 on his experience with the size he has as that is most likely the size I will get when I get one.

Did not mean to hijack the tread. BTW nice forums.

[revrnd]

Originally Posted by imkzru

Did not mean to hijack the tread. BTW nice forums.

Actually, you asked a good question. The 6 speed trannies are probably new to a lot of us & asking questions & making suggestions will help some of us down the road.

[rdsknfn_57]

I have an 06 , in my manuel it's called cruise grade braking, with the tow haul mode set and while going down hill and the transmission in drive ,i set the cruise control and it will down shift automatically without me touching the brake pedal only alowing me to drift 6 mph before down shiting, a few times on a really step hill i have aplied the brake, just depends on if it's a curvy road or not, SERIUOSLY thinking about adding an exaust brake . i know you can get them on a new truck but since my 06 is 5 yrs old ( bought in 05 ) and paid for with only 49,000 miles on it, it's hard to justify the price of a new truck.

[slpybeartx]

Originally Posted by revrnd

No Allison w/ the 5.3 L. The Ally is only available w/ the Duramax.

Beginning in 2009, the 1500 Silverados with the 5.3L and 6.2L vortec gas engines were offered with a new 6 speed automatic transmission. That is now standard for the 2010 model year.

Chevrolet Silverado 1500 Truck Review - Edmunds.com

Note: I do not belive that tranny is the same as the famed Allison 6 speed in the Heavy Dutys... but don't know for sure the code for it.

[revrnd]

The 6L80 is used in 1500 series pickups & the 6L90 in 2500HD & 3500HDs. There are built @ the GM Powertrain plant in Ypsilanti MI.

The Allison 1000 series tranny is the model used w/ the Duramax. It's built in Baltimore MD.

[slpybeartx]

Originally Posted by revrnd

The 6L80 is used in 1500 series pickups & the 6L90 in 2500HD & 3500HDs. There are built @ the GM Powertrain plant in Ypsilanti MI.

The Allison 1000 series tranny is the model used w/ the Duramax. It's built in Baltimore MD.

Thanks for those codes, revrnd! I am very intrigued by the "6L80". I would like to trade in my 2008 Z71 for a 2010 Z71 to pick up the new tranny and increased towing power.

Anyone have any comparison between the two?

[revrnd]

Actually those aren't the RPO codes, they're the tranny model designations.

The RPO codes for the 2011 2500HD & 3500HDs are:

MYD: 6L90

MW7: Allison 1000 series

I don't have any info for the 1500s.

[revrnd]

Originally Posted by imkzru

@Mjones12

I also have a 2010 Silverado LT Crewcab 5.3l engine with the tow group and was wondering when you go over mountains and the truck downshifts, what RPM are you taching? I just went from Virgina to West TN and going over black mountain on the down hill side the grade is 5% for about 6 or so miles and I found that every time I tapped my brakes the truck downshifted and I was taching between 4.5 and 5k RPM. To be honest I do not like this as it does slow you down, but when the speed limit is 65-70 and you have idiots that want to ride their brakes and truckers that want to ride a little close, this rapid decrease in speed I can see causing and issue. But beside that the RPM's has me concerned. Most V8 engines that I'm familiar with red line at 4k or 5k. My truck does not have any yellow or red line marked on the tachometer, but that high of RPM on a V8 can not be good. Do you know what the red line of this truck is?

What axle ratio & tranny does your truck have? Two examples:

6 speed trans'

4.10:1 axle when in 5th (0.85:1) = 3.48:1 final drive ratio

4.10:1 axle when in 4th (1.15:1) = 4.71:1 final drive ratio

3.73:1 axle when in 5th (0.85:1) = 3.17:1 final drive ratio

3.73:1 axle when in 4th (1.15:1) = 4.28:1 final drive ratio

W/ the ratios being what they are in the 6 speed, it's quite a drop going into 4th. That's probably what is causing what you're encountering and rightfully so. A greater than expected deceleration. My truck was ordered w/ the 4.10s (I'm a firm proponent of More's Law ). I was doing the math around the time it was being built (too late to change order) & realized what the final drive ratios were going to be. For whatever reason (whether a mistake or content change), my truck was built w/ the 3.73s. It turns out I'll probably be happier w/ the 3.73s.

Originally Posted by slpybeartx

Thanks for those codes, revrnd! I am very intrigued by the "6L80". I would like to trade in my 2008 Z71 for a 2010 Z71 to pick up the new tranny and increased towing power.

Anyone have any comparison between the two?

Everything you wanted to know about the recent GM automatic trannies:

4L60E Trans (LD Trucks):

1st: 3.06:1
2nd: 1.63:1
3rd: 1.00:1
4th: 0.70:1
R: 2.29:1

4L80E Trans (HD trucks):

1st: 2.48:1
2nd: 1.48:1
3rd: 1.00:1
4th: 0.75:1
R: 2.07:1

6L80 trans (RPO MYC) LD trucks & SUVs:
6L90 trans (RPO MYD) HD trucks:

1st: 4.03:1
2nd: 2.36:1
3rd: 1.53:1
4th: 1.15:1
5th: 0.85:1
6th: 0.67:1
R: 3.06:1

Allison Model 1000 trans (RPO MW7)
HD trucks w/ Duramax diesel:

1st: 3.10:1
2nd: 1.81:1
3rd: 1.41:1
4th: 1.00:1
5th: 0.71:1
6th: 0.61:1
R: 4.49:1
Note: 6th gear & manual gear selection capability was added for the 2006MY.

[Herk7769]

I have the Allison transmission option with my Duramax (it is ONLY available on the diesel). I LOVE IT.

Although a very expensive option when I ordered the truck (my dealer had NEVER ordered it "for the lot" before because of that), the trans shifts flawlessly and has an external filter that can be changed easily (even after every long trip if you want to since its a spin on). Tow/Haul mode uses all six gears (just changes the shift profile for when the shift occurs) and up/down shifts automatically for best uphill and downhill speed control. The top two gears are OVERDRIVE gears and we get pretty good fuel mileage hitched or not (though do NOT buy it for fuel economy as it is not much better than the stock 6 speed auto trans and the break even would be several lifetimes).

[revrnd]

Originally Posted by herk7769

has an external filter that can be changed easily (even after every long trip if you want to since its a spin on).

It's too bad that's not the case w/ all ATs. Would make maintenance easier & cheaper (less labour to do). Might make them live longer if people were to change the filter & fluid when needed.

[mjones12]

Originally Posted by imkzru

@Mjones12

I also have a 2010 Silverado LT Crewcab 5.3l engine with the tow group and was wondering when you go over mountains and the truck downshifts, what RPM are you taching? I just went from Virgina to West TN and going over black mountain on the down hill side the grade is 5% for about 6 or so miles and I found that every time I tapped my brakes the truck downshifted and I was taching between 4.5 and 5k RPM. To be honest I do not like this as it does slow you down, but when the speed limit is 65-70 and you have idiots that want to ride their brakes and truckers that want to ride a little close, this rapid decrease in speed I can see causing and issue. But beside that the RPM's has me concerned. Most V8 engines that I'm familiar with red line at 4k or 5k. My truck does not have any yellow or red line marked on the tachometer, but that high of RPM on a V8 can not be good. Do you know what the red line of this truck is?
On a slightly different note:
I'm also towing a little popup that has a dry weight of about 1200lbs. Your trailer has a dry weight of about 2600lbs. The truck can tow about 10k. From reading your post I'm seeing you are not having any issues towing that size trailer, but towing my little popup I'm finding it searching for gears when going up any size hill. I would love to buy the size trailer you have but I would like to hear from someone who has one and tows their experience?

Lastly this truck has a trailer brake controller, but for the life of me I can not tell how much stopping power I'm putting on to the trailer. Have you found a way to tell or is the amount done automatically?

I kind of like the feature you're talking about. I tow up and down Black Mountain a few times a year - but only once since I got the new truck - and I'm pretty sure the speed limit is 55 until you get to the bottom. Sorry, I didn't notice the RPMs but I'll look next time. But if you're unhappy with the gear it selects for you, why not put it in manual and select the gear that feels right? That feature works very nicely on the 2010 LT.

I think I tow at about 4,000 pounds. The gross weight for the trailer is around 5,000. As for the brake controller, I use the Prodigy and set it at 6.5. Just had my trailer brakes checked after a year, and they said it was wearing normaly, so I must be estimating it about right. The service guys that installed the controller for me suggested I find an empty stretch of road and adjust the controller while braking, with the goal to make it feel as if the whole rig is braking as a unit.

Going up Black Mountain, my six-speed transmission pulled it like a charm, no hunting. Much, much better than pulling the same trailer with the 2005 with the four-speed and 4.8 liter.

[rockwood06]

Originally Posted by revrnd

The 6L80 is used in 1500 series pickups & the 6L90 in 2500HD & 3500HDs. There are built @ the GM Powertrain plant in Ypsilanti MI.

The Allison 1000 series tranny is the model used w/ the Duramax. It's built in Baltimore MD.

My neighbor just down the street from me works at the Allison plant on Pulaski Highway (Rt40), in Baltimore, the last time I had talked to him he said that his job in Baltimore may be over soon the company was going to move the plant to Mexico I had heard about this in the beginning of the Summer but at this time I don't know what is happening with his job.

[rockwood06]

One thing I don't like about the 1/2 ton or the heavy duty 1/2 ton is the receiver, a class III is standard, when I put my hitch into the receiver there is too much play and GM will not supply a class IV for any 1/2 ton, the class IV is standard on the 3/4 ton only, with a class IV the hitch fits snug as it did on my 3/4 ton GMC Suburban, and from what I understand one can not get an after market class IV receiver for a GM 1/2 ton pick-up at least not for my 2008.