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Having to say goodbye to 4wd Auto makes me sad.

Remanaz

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But in the end, more ground clearance and a more level stance will likely make me happy enough to not just be a wash.

If you haven't guessed it yet, I am going to be adding a plus 2 lift to my truck. I just ordered the Ready Lift SST plus 2" lift. Amazon is selling them for $602. They had a damaged box listing for $402 and I just couldn't pass up a $200 savings. I mean technically it is a $260 savings since the normal price is $659 so I am saving 1/3 of the price. Hopefully all parts are there and they are not damaged. Cause then I will just have to live with 4wd Auto for a little longer.

If all goes well with delivery and parts inspection, I will still have a hurdle to jump. That is to be able to install this without my better half knowing. Lol. She doesn't want me to lift it or even level it. She says it is already hard enough for her getting in and out even though I have steps/bars. Looks wise she would know it was changed. She doesn't pay enough attention to that stuff. I am hoping the change in getting in and out is not as noticable as she thinks it will be. She seems to be thinking like a 6" lift type of height I believe. I am hoping by the time she finds out she will have gotten used to getting in and out of the lifted version. Then I can shrug my shoulders and ask if it is really any different.

Wish me luck. If I disappear you know why!
 

Baz

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That’s funny, good luck buddy! I’ve been thinking about pulling the same stunt with my wife too.
 
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Remanaz

Remanaz

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Looks like it should get here Wed. This is a good day for getting it in the house while she is sleeping. I will have to wait to install it till the following week on Friday and get the alignment close. I will be taking it in the following Monday for its first oil change and I can have them do the actual alignment at that time. She will be none the wiser if all goes well.
 

Jmzvet

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Why does lifting it 2in cause it not to work in 4wd auto? Will the entire drive line be destroyed?
 
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Remanaz

Remanaz

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These lifts and most of the 2" lifts for the Trail Boss do not include dropping the differential. By not dropping the differential the CV angles are increased. The reports out there are of vibration issues in the drivetrain when using 4wd auto. The lift manufactures also provide disclaimers suggesting not to use 4wd auto with their product installed.
 

Brando

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Why does lifting it 2in cause it not to work in 4wd auto? Will the entire drive line be destroyed?
This may have been said before, but my understanding is that you can still use 4wd, shifting into 4WD should not be a problem from Neutral, but in auto 4WD engaging at 30+ MPH may cause a problem with the lift and angles being more significant etc...
 

Jmzvet

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This may have been said before, but my understanding is that you can still use 4wd, shifting into 4WD should not be a problem from Neutral, but in auto 4WD engaging at 30+ MPH may cause a problem with the lift and angles being more significant etc...
Makes sense.
 
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Remanaz

Remanaz

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Well it looks like Amazon is going to deliver a day early. Darn them. They are fooking up my plan. Glad we just got a nice new reclining couch for me to sleep on.
 
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glopez1204

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These lifts and most of the 2" lifts for the Trail Boss do not include dropping the differential. By not dropping the differential the CV angles are increased. The reports out there are of vibration issues in the drivetrain when using 4wd auto. The lift manufactures also provide disclaimers suggesting not to use 4wd auto with their product installed.
Let me ask a stupid question, can we buy diff drop kits separately? would that fix the problem? I am looking into this leveling kit as well but do not want to lose my auto 4wd
 
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Remanaz

Remanaz

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Let me ask a stupid question, can we buy diff drop kits separately? would that fix the problem? I am looking into this leveling kit as well but do not want to lose my auto 4wd
Sorry for the delayed response.

First let me just put it out there that the lack of a diff drop info is what I have read on the forums. So I may have been guilty of parroting misinfo. I will say that it seems very plausible though seeing that the angles are increased a good bit. For 6"+ lifts (4"+ for the Trail Boss and AT4) they include diff drops to keep the CV angles near stock. I did not see this response when I was reading the Q/A section on the product page many months ago but now I see that they are saying
We dont suggest 4wd auto to be used due to the larger lift and tires you can see a vibration that is caused by the vehicle sending too much torque to the front driveshaft as it can no longer determine how much is needed due to the lift. If you run it in 2wd, 4hi or 4low it wont have any vibration. You can run 4WD auto and it wont cause any damage but it will likely have the vibration issue.

This doesn't make any sense to me though. There are no electronic sensors monitoring the height of the vehicle or the suspension angles themselves. I would think the wheel speed sensors are used to determine the torque needed to be sent front to rear. With larger tires the wheels speed sensor will be off. This could be what they are implying without saying it BUT, and it is a huge BUT, there are separate wheels speed sensors at each corner and if you are using the same size tires front and rear then your sensors will be off equally. If they are off equally then the computer should still send the same amount as it did with the stock size tires. I could be wrong though. I am not a GM engineer nor do I have complete knowledge of all the systems in these trucks. I have in the past been an ASE certified mechanic for a GMC dealership with one of my ASE's being steering and suspension. While there I installed more than a few 6"-8" lifts form Pro Comp and Fab Tech. Basically I have a little bit of understanding of the mechanics of our trucks. The electronics, however, has advanced since I worked on cars for a living. So take this input with a grain of salt or perhaps 2 grains.

I did install the lift. Do to tools breaking on me including my jack, I ended up lifting the front first then the rear a few days later. During this time I drove the truck around town and on the freeway in 2wd and in 4wd Auto with just the front level and then again with the full lift installed. My first day was raining the rest have been on dry ground. I am running the stock 275/65/18 Duratracs with 1.25" spacers. I did not notice any new vibrations or anything different with either setup. It could be that I am just not that sensitive to this vibration others have felt. Who knows. Regardless, I have no issue currently using 4wd Auto when I need it.
 
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Remanaz

Remanaz

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As said above lift is installed and I have been driving in and out of 4wd auto without feeling this vibration issue. Due to tools breaking on me the install did not go smoothly. But that was no fault of Ready Lift. First was my spring compressor was not strong enough to compress these springs. The bolt was benoding and on one side the clamp assembly locked up to where I could not turn the bolt anymore causing it to be stuck on the spring. DOH! I had to go buy a new set and luckily Harbor Freight just opened up just down the street. That one worked well and I was back up and working on the lift again. When moving to the rear my floor jack decided that the fluid level was now too low to work, It was late so I stopped there at that time. This did allow me to drive it around in 4wd Auto and to take measurements with just the front leveled. I did the same after installing the rear portion.

The measurements showed something interesting. I hadn't really thought about it before going into this but I am glad to have had the opportunity to see this and I think others should be aware of this. That is that when you level just the front you reduce your departure clearance. In other words, the hitch will be lower than before. Taller tires can fix this. The following measurements will include a B (before), F (front only) or an A (all lifted) in front of the number. Measurements at wheels taken at top of tire lugs (6500 miles exactly on before measurements) as close to center of axle as I could tell and the wheel well arch directly above. I should have measure the very front at the tow hooks but I used the bottom of the front caps forward of the wheel openings in front fenders.

Drivers Front: B 8 1/4 F 10 1/4 A 10 1/4
Pass Front: B 8 F 10 A 10
Front: B 23 5/8 F 25 3/4 A 25 5/8
Drivers Rear: B 9 3/4 F 9 5/8 A 10 5/8
Pass Rear: B 9 1/4 F 9 3/16 A 10 1/4
Bottom Hitch: B 18 5/8 F 17 3/4 A 19 3/16

I also took before and after the full lift comparison pics with another Silverado 1500 and a Sierra 2500. But I have to stop here for now as I need to get ready for work. I won't have access to these pics until tomorrow this time frame. Stay tuned........
 
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Remanaz

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Here are the pics. Sorry that they are dark. I took these at work and I work at night. The first truck is a white 2019 W/T with a 2" front level and 32.x" tires. I am not sure the profile of his tires but they were 285 17's. They look similar size to our stock 18" Duratracs. I tried my best to get good shots to show height differences. In the front view pic the mirrors tell a lot of the story. At the back side view I did not get the same camera height from the looks of it. But I can see that there is change in the level of my truck.




BB vs W front before.jpg
BB vs W front after.jpg




BB vs W hood before.jpg
BB vs W hood after.jpg




BB vs W bed before.jpg
BB vs W bed after.jpg
 
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Remanaz

Remanaz

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The second truck is a 2020 Sierra 2500. This thing is a beast. It has a 2" lift and 35" tires with +44 offset. He also cranked the torsion bars up just a tad to get the truck perfectly level. You can see the level angle differences in the bed top view pics.


BB vs G front before.jpg
BB vs G front after.jpg




BB vs G hood before.jpg
BB vs G hood after.jpg




BB vs G bed before.jpg
BB vs G bed after.jpg


I am not sure what happened to the before pic of this one.

BB vs G bed2 after.jpg
 
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