"Service 4WD" - Master Thread

humer101 said:

They to slow [emoji222]

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Off topic but are you changing your wheels? Didn't know what was up with the sig pic. The black wheels would look nice.

hosseface said:

Off topic but are you changing your wheels? Didn't know what was up with the sig pic. The black wheels would look nice.

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Wife want those she will buy with own money,lol is OK with me will set the original 20" with snow tires for winter.
[emoji111]

Why no fix yet?

I find it really hard to believe GM hasn't found a fix yet. It's been months, and a major feature of their best selling line is still not working?

Just had the same problem today. Vehicle is a 2015 Yukon XL Denali, produced last week of August and delivered early September.

I have been driving the vehicle mostly in 2WD mode in dry weather conditions. Recently with fall rains in the Midwest, I switched to Auto mode. I have been driving in Auto mode for about a week without noticeable difference and without problem....until this morning.

I drove all morning in Auto mode, making several stops. Conditions were a light drizzle/rain. After my last stop, I started the ignition and backed out of my parking space. It felt like the parking brake was applied, but it was not. (I never use the parking brake). Within seconds, the Service 4WD light came on. From that point forward, it was clear the transmission was stuck in 4WD mode....reduced turning radius, rubbing/grinding noise and increased friction in transmission causing the vehicle to stop when coasting in idle.

I immediately called my local dealer. They got me right in. They have not seen many 2015 models come through service yet and have not seen this issue at all yet. I showed them the info from this forum. They performed the Transmission module reprogramming and the issue was resolved. Seems like a "glitch" similar to when your home computer needs to be restarted - or a program needs to be reloaded.

They said there is not a recall for my vehicle or a known bulletin about this exact issue. The previously mentioned bulletin in this thread was from July and pertained to transmission going into "neutral" spontaneously. However, the same "fix" applied.

Hopefully, GMC will take notice and find a permanent solution. For now, I'm going to stay in 2WD and switch to 4WD High manually when needed.

My wife backed out of the driveway yesterday and service 4 wd message appeared. She called and thought the parking brake was on. We've had ours in 2wd the entire time. Anyone else had it with just using 2wd? Bought the car out of state and called a local dealer who said they havent heard of the issue in the new models. Should I avoid them for repairs or just tell them to reflash the transfer case? This is crazy to still have this issue

JayBanks9 said:

My wife backed out of the driveway yesterday and service 4 wd message appeared. She called and thought the parking brake was on. We've had ours in 2wd the entire time. Anyone else had it with just using 2wd? Bought the car out of state and called a local dealer who said they havent heard of the issue in the new models. Should I avoid them for repairs or just tell them to reflash the transfer case? This is crazy to still have this issue

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I have the last update yesterday they do for me, I just bring for regular service and they update with the latest version.
Hope work now.

Dealer reprogrammed the trahsfer case and its back to normal. Fingers crossed it isnt a reoccuring thing.

Round 2 of "Service 4WD"

Well it happened again. We had a cold snap with some snow so I put it in "Auto" for safety reasons. Low and behold it happened again stuck in 4WD the next day. Took it back to the dealership, they "said" they tested the range sensor and it passed. They still couldn't get it out of 4WD so they had to call the manufacture. Turned out they had to "replace" the encoder motor. Was told by one of the service reps to "never" leave it in "Auto" leave it in 2WD until you need it. If you read in the manual section 9-38 no where in that manual does is say not to leave it on "Auto". It did say you would get better mileage then 2 wheel drive. I reminded them that Arizona has a lemon law and if they can't fix it I will be happy to go that route. Hopefully I won't have to because I love my Tahoe.

It snows in Arizona? I seriously didn't know it did that in AZ

Mountaingirl45 said:

Well it happened again. We had a cold snap with some snow so I put it in "Auto" for safety reasons. Low and behold it happened again stuck in 4WD the next day. Took it back to the dealership, they "said" they tested the range sensor and it passed. They still couldn't get it out of 4WD so they had to call the manufacture. Turned out they had to "replace" the encoder motor. Was told by one of the service reps to "never" leave it in "Auto" leave it in 2WD until you need it. If you read in the manual section 9-38 no where in that manual does is say not to leave it on "Auto". It did say you would get better mileage then 2 wheel drive. I reminded them that Arizona has a lemon law and if they can't fix it I will be happy to go that route. Hopefully I won't have to because I love my Tahoe.

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Lest bust they ass everyone keep on 4wd , this is a hazardous situation now.
[emoji35]
They have to fix by now.