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Discussion Starter · #1 ·
Hi all, first time poster. As you can guess from the title, I have a 2011 Suburban with a 5.3 engine and the standard towing package. While the vehicle tows my 2500 pound boat and 2000 pound travel trailer fine on the relatively flat roads of Michigan, it really struggles to get the travel trailer to the top of some of those long inclines in Wyoming and Montana. I don’t need to be the first truck to the top of the mountain but we often have to pull over to let the transmission cool down. On this trip the tranny temp hit 238 before I found a safe place to let it rest

Are there any reasonably priced upgrades I can make to give me more towing capacity in those situations or did I pick the wrong truck?

Thanks
 

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Tru Cool 40k trans cooler to replace your tiny stock cooler. And a Black Bear Performance mail in tune to solve your power problem.
 

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Your truck should pull 2 thousand pounds and not know it's back there, mine does.
What transmission do you have?
Do you have Tow/Haul?
Do you have the M selection on the shift lever?
 

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Discussion Starter · #4 ·
I purchased the truck used and do not have the original window sticker so I don’t know which transmission I have. How can I find out without going to the dealer?
 

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I should have been a little clearer, is it a 6 speed, or a 4 speed?

All of the build codes are on a sticker on the inside of the glove box door.
 

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@RayVoy it would have to be a 6l80 for a 2011. Pretty sure 2007 was the last year of the 4 speeds.
 

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Discussion Starter · #7 ·
It is a 6 speed tranny with tow / haul and the M manual settings. I use tow / haul all the time and the manual settings for engine braking on the downhill side of things.
 

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I'm pretty sure your right Reb.

So then he should have the manual shift selection and should be able to downshift manually whenever he hits a hill.
 

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Discussion Starter · #9 ·
Ok, it sounds like it may be user error on my part then.

I currently only use Manual mode when descending long or steep hills with or without a load to take advantage of engine braking. Are you guys saying that I should also use Manual mode when climbing long and steep hills with a load? If that is the case what are the safe speeds per gear or max RPM I should allow?

BTW, I under that Manual mode reduces the gear range of the the transmission, I just thought that an automatic transmission, especially in Tow/Haul mode would control that when climbing better than I could do it manually.
 

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I find it usually takes some experimenting to get it right.
When you use manual, the transmission performs as it would in Drive, shifting normally from 1 to 2, from 2 to 3 until it reaches whatever gear you have selected.
If you have selected 4, the transmission stops shifting when it reaches the 4th gear.

If you go to Drive and select Tow/Haul, the transmission will shift from 1 through all gears and into 6; but it will shift at different engine speeds than if you had not used T/H.
It will also increase the internal clutch pressure to prevent slippage.

The trick is to increase engine speed when you need more horse power, such as climbing a hill.
The only way we have to do that is downshifting.
 

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Make sure you have the correct sized tires on the Burb. The before every trip make sure the Burb tires and the trailer tires are fully inflated. Upgrading the trans cooler or adding one if you don’t already have one would be nice. Also maybe swapping the gear ratio from what you have probably 3:73 to a 4:10. But that can be pricey esp if you have 4x4.
 

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Sounds to me that you're running out of RPM's & HP. Take a picture of your Service Parts Identification Label in the glove box and post it so we can see what you're working with. I doubt you have a 3:73 or 4:10, unless it was a special order.
 

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Discussion Starter · #13 ·
I’m running Michelin Defender LTX M/S 275/55R20 tires which I cold fill to 42 pounds, 2 pounds under max.

167189
 

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You have a 3.08 differential (GU4) Good for gas mileage but not ideal for pulling a trailer.
 

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With a rear ratio that tall, you should stay out of 6th gear, use 5 on the level areas and 4th on the hills.

I have the same size tires, I run them around 35 cold when not towing and 38 when towing. Pulling 2500 won't add a lot of extra weight to the tires.

Are you using a weight distribution hitch.
 

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Discussion Starter · #16 ·
Yes, I have a 4-point Equil-I-zer weight distribution hitch.

So maybe I should back the tire pressure down some.
 

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@Zetta Oh no, you have soccer mom ratio. I wouldn’t tow a lawn mower with a 3.08. But, if you must, keep it cool, use manual mode and keep the RPMs high and that’s about all you can do.
 

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@Zetta Oh no, you have soccer mom ratio. I wouldn’t tow a lawn mower with a 3.08. But, if you must, keep it cool, use manual mode and keep the RPMs high and that’s about all you can do.
Sad, but so true. Since the 90's right up until today, these Suburbans are built for luxury and fuel economy. For the most part they are "cruisers" and "grocery getters". A big difference between these and the "beasts" that were built in the 60's, 70's & 80's. Keep the transmission cool, maybe add a higher capacity pan, and stay out of 6th gear when towing. Good Luck!
 

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Discussion Starter · #19 ·
Interesting that you use the “soccer mom” term as that is exactly how I have come to describe this version of the utility vehicle I had come to love I enjoyed my last two which were actually built for hauling and utility work. While I like the improved turning radius, cushy seats and updated amenities, I am very disappointed with the “wimpization” of what used to be a hard working truck.

It’s my fault for not doing more research before buying. Even my 2001 Yukon XL had more guts than this one.

Thanks for all of the input. I will probably be back with more questions soon.
 

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The first thing I do when I'm interested in a "new to me" vehicle, is take it for a test drive and while out in vehicle, I take a picture of the build codes on the glove box door.
 
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