2009 Yukon XL Denali - Front & Rear Suspension Refresh

[petethepug]

This pic sums it up for me. Perfect day, perfect vehicle.



Not trying to be the Debbie Downer here but if you’re towing and potentially doing it with passengers as well as using it for a snow limo, wouldn’t it be a good idea to retain all the redundant safeguards of the z55 since it’s tied into all the other trucks stability systems?

The only scenario you can’t predict when you’ll want full blown micro second calculations made is after z55 is defeated and some FDS has hit your truck or forced you to avoid a collision.

I would never want to explain to my insurance or a State Trooper what the resistor is zip tied on to the body of my truck when it’s upside down from an accident another drunk, uninsured guy caused. That’d potentially be enough for the guy that caused the accident to flip things and him / insurance blame me for disabling a safety system.

Unlikely, yea. Possible, definitely. My family and the possibility of having regrets that 1% of a mod I did may have avoided bodily harm or worse, nope, pass.

If it were my personal toy I used for mostly Non Family stuff, that’s another situation entirely.

 

[petethepug]

I know your hands are full with LT swapping that new motor in. My Indi wasn’t to happy about doing my trans 2x either.

The biggest difference you’ll feel in refreshing the suspension is, new struts of course, but new bushings and poly on the sway bars even makes the passengers happier. If you can pull it off get bigger sway bars to give it a better than new ride.

Check out my aluminum suspension rebuild page where you can swap in the 15-19 Denali alum susp parts when you’re refresh’g it. The cost is about 5-10% more but you’ll drop over 30lb off each front axle.

The part numbers listed for the Esky are the same as the Denali except for the z55 struts. I’m on a budget so the approx $1.3k in parts accumulated for the job from internet shopping equates to almost $4k in dealer prices.

Keep us posted on the motor transplant.

 

[KraftMatic87]

I know your hands are full with LT swapping that new motor in. My Indi wasn’t to happy about doing my trans 2x either.

The biggest difference you’ll feel in refreshing the suspension is, new struts of course, but new bushings and poly on the sway bars even makes the passengers happier. If you can pull it off get bigger sway bars to give it a better than new ride.

Check out my aluminum suspension rebuild page where you can swap in the 15-19 Denali alum susp parts when you’re refresh’g it. The cost is about 5-10% more but you’ll drop over 30lb off each front axle.

The part numbers listed for the Esky are the same as the Denali except for the z55 struts. I’m on a budget so the approx $1.3k in parts accumulated for the job from internet shopping equates to almost $4k in dealer prices.

Keep us posted on the motor transplant.

Thanks for the tips! Lookin to do suspension work this summer along with new fuel pump. We’ve been driving on the new engine for two weeks and alls well so far. That last block dropped an intake valve in cylinder 3 and made some nice tasty piston McNuggets. I have two and a half years before the engine warranty is up so if I can make a it a year with this block we should be hopefully be good.

 

[KraftMatic87]

I ended up installing a pair of KYB SRM 4079 Truck-Plus quick struts. I have bypass resistors coming in the mail tomorrow and I’ll be installing those to disable the service suspension light. I’ll be installing Moog 81071 springs in the rear with a pair of Bilstein 4600 shocks this weekend to complete the auto/air-ride delete, followed by an alignment. I may opt to replace the compressor and add air ride shocks in the future but for now I think I’ll be happy with the passive shocks.

Very impressed with how the KYBs ride. The front sits about an inch higher than before. They are firm but very responsive, and they recover quicker from bigger bumps than my soft worn out autoride shocks. My stock struts were so far gone anything would have been an improvement.

The KYBs were $500 for the pair. The Bilstein 4600s were $160 for the pair, and the Moog rear springs $70 for the pair. Resistors were $24 total, so I’ll be out $750 to replace all four corners. Definitely worth every dollar!

My next project will be replacing upper and lower control arms and inner and outer tie rods sometime in July or August. Someone help I can’t stop buying parts!

 

[petethepug]

As soon as the resistors go in the truck is being told it’s driving 70 mph straight down the highway when you it may actually be ass end out in a tailspin trying to avoid an obstacle in the next lane.

ABS, Stabilatrac & Yaw sensors will be totally clueless where your wheels are and go into Godzilla mode or …

The truck may simply barrel roll. It is being fed data like it’s being picked up by Godzilla because all the wheels have the exact same bogus readout from the resistors communicating with the stability program.

 

[KraftMatic87]

As soon as the resistors go in the truck is being told it’s driving 70 mph straight down the highway when you it may actually be ass end out in a tailspin trying to avoid an obstacle in the next lane.

ABS, Stabilatrac & Yaw sensors will be totally clueless where your wheels are and go into Godzilla mode or …

The truck may simply barrel roll. It is being fed data like it’s being picked up by Godzilla because all the wheels have the exact same bogus readout from the resistors communicating with the stability program.

View attachment 427032

I understand that the resistors are ‘fooling’ the ECU but here’s my question:

The ride height sensors are not being touched because I’m not lifting the truck. I only am putting resistors on the dampener connections for the front shocks that plugs into the top of the strut. I’m genuinely curious how that would affect my wheel speed sensors or put the vehicle into Godzilla mode?

When I do the rear shocks I will plug a resistor into the sensor that plugs into the shock itself. The rear ride height sensors will not have resistors plugged into them either.

 

[petethepug]

All the live data that’s fed through the rear suspension module and other sensors are tied into the active suspension calculations for when & how much dampening & rebound the struts should get.

Later models after ‘10 also incorporate active sway control for towing, auto hill descent braking and uphill roll back brake assist when stopped.

The VSC or vehicle skid control is one of the most important features of this vehicle and why it was rated a 4/5 for rollover protection and 5/5 on everything else by the NHTSA.

Just be aware you’re knee capping the system that will totally stiffen to the max or soften one or more struts to prevent trailer swag or rollover.

Not trying to be dark, just pointing out the really of the dark side of folks that take zero responsibility for owners and their families who sell these “money savings parts”. Ask a dealer about it and all you’ll get is “NOPE, won’t do it”.

 

[KraftMatic87]

All the live data that’s fed through the rear suspension module and other sensors are tied into the active suspension calculations for when & how much dampening & rebound the struts should get.

Later models after ‘10 also incorporate active sway control for towing, auto hill descent braking and uphill roll back brake assist when stopped.

The VSC or vehicle skid control is one of the most important features of this vehicle and why it was rated a 4/5 for rollover protection and 5/5 on everything else by the NHTSA.

Just be aware you’re knee capping the system that will totally stiffen to the max or soften one or more struts to prevent trailer swag or rollover.

Not trying to be dark, just pointing out the really of the dark side of folks that take zero responsibility for owners and their families who sell these “money savings parts”. Ask a dealer about it and all you’ll get is “NOPE, won’t do it”.

I understand what you’re saying now. I don’t ever plan to tow with this vehicle and that was one of the reasons I felt comfortable going with passive suspension. I never was planning to buy Z55 autoride / electronically dampened struts for the front anyways because they were $500/piece. But in a few years when kids get older and we aren’t paying for daycare I may buy a new compressor and air ride shocks for the rear once these Bilsteins start showing their age.

 

[petethepug]

Again, not trying to be Debbie Downer. Front z55 are $3h ea and rear are $3h ea. Both have a 5% off discount. All guaranteed for life. Key word, life.

I did 3 kids in our 08 YXL Denali and locked up the truck in a full panic stop just once at 75 in the 6 years of ownership. They literally steer when pulsing and locking up (and letting off) the struts and wheels. GM’s system got 3 TONS of truck over two lanes and down to 45 into an empty lane.

My wife pee’d her pants. The kids we’re asleep. I’m lucky to tell a story about it than explain to some big shot patrol investigator trying to make a name for himself on what them devices are hooked up to the suspension.

 

[KraftMatic87]

I finished swapping out the rear today for my air-ride delete. Bilstein 4600 with Moog 81071 coil springs and Moog K160072 insulators on top and bottom of the new springs since the old ones were worn out. I’m completely impressed with the KYB / Bilstein combo, and the truck handles much better. The handling is firm and the new shocks / struts are way more responsive than my old worn out ones.







Glad I rolled the dice. Truck drives great and handles much better than before. Total cost was $750 in parts for front and back.