Troubling issue with 05 tahoe

[Mccool]

So this has been nagging me for a few months now in the back of my head and I would like y'alls opinion.

A while back my wife and I had the tahoe about 20 miles out in the mountains camping. We broke camp to leave in the morning and that required driving up a steep trail we had descended the day before to get to a nice camp spot. This hill was pretty steep, walking up it I could put my hands in front of me and touch the ground. The tahoe really struggled to get up it even though it was smooth dirt and not rutted out. The first 2 times i tried in 2wd and made it half way up, i had the tahoe floored and we were sitting still not spinning the tires, then i tried it in 4hi with the same results. Finally i tried in 4hi but got a "running start" and made it but just barely.

The whole time I was thinking "my old Rubicon would've walked up this in 2wd without breaking a sweat."

Obviously I don't expect my tahoe to perform offroad like the jeep, but I really didn't think this hill would pose a challenge. So why did it struggle? A lack of torque? Improper gearing? Something else?

Any thoughts?

 

[pigsammy]

"..floored and sitting still, not spinning the tires..."

That would concern me.
I'm not a mechanic by any means, but a healthy transmission behind a good engine should at least spin the tires, right?
Would the angle starve a torque converter of fluid?

How has it run/shifted since then?

 

[NevadaLover]

Most probably a gearing issue, alot of tahoes and suburbans were made with soccer mom gears, 3.42 were some of the most common, look in the glove box for the rpo code sticker then go to this website:
http://www.rpocodes.com/GM-RPO-codes/gmrpocodesGthroughM.html
It will tell you which gears you have!

 

[Mccool]

Thanks for the input guys.

Pigsammy- I agree, I really expected the tires to break loose. The truck has shifted and ran fine since, no issues at all.

Nevadalover- it has the g80 and 3.73's

 

[NevadaLover]

Did you try 4lo at all? Got to remember that this rig is alot heavier than your old rubicon and that hill might have been steeper than you think, next time try 4lo and with the G80 and 3.73s it should walk right up that hill!

 

[Mccool]

Did you try 4lo at all? Got to remember that this rig is alot heavier than your old rubicon and that hill might have been steeper than you think, next time try 4lo and with the G80 and 3.73s it should walk right up that hill!

It's been a while now but I don't think I tried 4lo. There was no mud, sand or rocks and I wasn't spinning the tires so I didn't attempt 4lo from what I remember.

You're right though, it was pretty steep. Walking up it was a chore without using my hands. And yeah, I don't expect it to behave like the jeep but I'm fairly confident my old, heavy crewmax tundra would've handled it easily as well, though that had 400hp and 4.30 gearing.

Our adventures going forward involve a 2k pound trailer so I was just curious if the tahoe had a shortcoming I should address like power or gearing. I'm not looking to rock crawl but I'm also not looking to strand my wife and 4 kids 30 miles from help either.

The hill was off the paradise divide trail by the way, near the top at shoffield pass near crested Butte Colorado

 

[HenryJ]

Does it have traction control? My 2005 Avalanche does. With it active (you have to push the button to disable) it is designed to not spin a wheel. You can press the throttle to the floor and it will back it off so that it does not spin a wheel. This sounds like what you might have experienced?
This system is not active in 4lo

 

[Mccool]

Does it have traction control? My 2005 Avalanche does. With it active (you have to push the button to disable) it is designed to not spin a wheel. You can press the throttle to the floor and it will back it off so that it does not spin a wheel. This sounds like what you might have experienced?
This system is not active in 4lo

That does sound like what was happening but I don't see a traction control button anywhere

 

[Dock Rocker]

My guess is you were a victim of traction control and or torque management by the ecu.

The motor unless completely neglected will make more than enough torque to turn the tires.l unless the ECU is pulling all the timing and making it fall on its face.

Spend $250 get a black bear tune and make sure you tell them what was going on. They can make sure the engine has the timing it needs.


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[Mccool]

My guess is you were a victim of traction control and or torque management by the ecu.

The motor unless completely neglected will make more than enough torque to turn the tires.l unless the ECU is pulling all the timing and making it fall on its face.

Spend $250 get a black bear tune and make sure you tell them what was going on. They can make sure the engine has the timing it needs.


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The motor seems to have enough power during normal driving. I'll research the tune, I don't mind spending the money if it will fix the issue and give me peace of mind.

 

[Dock Rocker]

My guess is you were a victim of traction control and or torque management by the ecu.

The motor unless completely neglected will make more than enough torque to turn the tires.l unless the ECU is pulling all the timing and making it fall on its face.

Spend $250 get a black bear tune and make sure you tell them what was going on. They can make sure the engine has the timing it needs.


Sent from my iPhone using Tapatalk

The motor seems to have enough power during normal driving. I'll research the tune, I don't mind spending the money if it will fix the issue and give me peace of mind.

This just came to me. Were you riding the brake just a little to prevent it from rolling back?

If so GM has “brake torque management”. It will actually bring your timing into negative numbers to prevent power braking ie foot on brake 100% throttle to roast the tires. This will take all the guts out of the engine instantly.


This is easily tuned out.

Sent from my iPhone using Tapatalk

 

[Mccool]

This just came to me. Were you riding the brake just a little to prevent it from rolling back?

If so GM has “brake torque management”. It will actually bring your timing into negative numbers to prevent power braking ie foot on brake 100% throttle to roast the tires. This will take all the guts out of the engine instantly.


This is easily tuned out.

Sent from my iPhone using Tapatalk

I don't think so, but it is possible. I appreciate the help!

 

[HenryJ]

That does sound like what was happening but I don't see a traction control button anywhere

Mine is to the right side of the radio.

Just behind my laptop in this pic:

If you do not have it ... is yours AWD? Does it have the four button transfercase? (2WD-Auto 4X4-4WD-4LO)

I will say that I have only been frustrated once. Stuck in a snow drift. It just would not spin when I needed it to power out. Turns out I had an encoder (transfercase) motor failure and the front differential would not lock in. Shifting to 4 lo got it in 4x4. That issue is long since repaired...twice
Do check the RPO code list in the glove box. Mine is geared lower than most with the 4.10 gearset. I need the taller tires to get decent fuel mileage. 3.73 are Ok..3.42 are going to be a struggle with anything other than the stock tire size.
I personally have not paid for a "custom tune". Others have boasted about the gains. That may be , but I am fine with a Bullydog to adjust for tire size. I do have some performance additions for both the engine and transmission. More toward performance, mileage and dependability while pulling a light trailer. BLT Offroad Avalanche

 

[Ducky's Dad]

My wife's '04 Escalade probably has a similar drivetrain to the '05 Tahoe, although a bit more displacement and power. The Escalade's traction control does cut off torque whenever the system senses lack of traction. Even a little wheel spin is sensed as lack of traction and the torque shuts off instantly, but the engine sounds normal. When Motor Trend took a bunch of highend full-sized SUVs out to the desert for a comparison test when these things were new, the Escalade was the only one that got stuck in the sand, because the computer shut off torque to all four wheels. It's That Great GM Feeling!

 

[Mccool]

Mine is to the right side of the radio.

Just behind my laptop in this pic:

If you do not have it ... is yours AWD? Does it have the four button transfercase? (2WD-Auto 4X4-4WD-4LO)

I will say that I have only been frustrated once. Stuck in a snow drift. It just would not spin when I needed it to power out. Turns out I had an encoder (transfercase) motor failure and the front differential would not lock in. Shifting to 4 lo got it in 4x4. That issue is long since repaired...twice
Do check the RPO code list in the glove box. Mine is geared lower than most with the 4.10 gearset. I need the taller tires to get decent fuel mileage. 3.73 are Ok..3.42 are going to be a struggle with anything other than the stock tire size.
I personally have not paid for a "custom tune". Others have boasted about the gains. That may be , but I am fine with a Bullydog to adjust for tire size. I do have some performance additions for both the engine and transmission. More toward performance, mileage and dependability while pulling a light trailer. BLT Offroad Avalanche

I do not have this button, but I do have the 4wd 4 mode with 4hi and 4lo.

I also have the 3.73's and g80