Uneven Squat After Bilstein 5100 Install

Hello,
I installed some Bilstein 5100's in the rear of my 2011 Crewmax TRD earlier this year. After the install I noticed that the squat in the back with a load (towing or in the bed) is quite different - about 3" lower on the drivers side.
What could be causing this?
Bad leaf spring?
Something wrong with the new shock?

Here are some pics with a full load in the back to show the difference:



Drivers side gap




Passengers side gap


Any suggestions you have for me to chase down the issue are appreciated.

Thanks

 

Check the body mounts bushings

 

I took a quick look under there at them and didn't see anything out of whack. They both looked essentially the same on each side. Is there anything in particular to look for with them or should it be obvious is they are contributing to this?

 

Is it possible one of the shocks got blown out and is sagging?

How do your leaf springs look? If its the leaf springs, you should be able to visual see a difference in their arc at near 3 inchs of height difference.

 

It seems like it may be an issue with the leaf springs but I'm not sure what exactly. These pics are still with it under a heavy load. The drivers side is sitting flat on the lowest portion of the leaf spring where the passengers side has a gap.
Is this indicative of an issue with the leaf springs on the drivers side?
Or could it be due to the gas tank? It's just over half full here.
I'm not seeing any obvious cracks or breaks on the drivers side. Plus, other than the height difference, there are no ride quality issues that I notice.

My understanding has always been that the shocks aren't the driver of ride height, but of dampening.
For what it's worth, I installed the 5100's with the truck on the ground and it hasn't been in the air since that install. Both shocks were fully extended for a short period just prior to installation, but if this is shock related, maybe it needs to reach full extension again or a few times?

Drivers side


Passengers side

 

I am not sure if the load you have in your bed in those pictures are biased to the driver side, but I am 100% sure the issue is your leaf springs. They look like they have a fair bit of rust so they are probably shot to shit. Even with the gas tank full, there should not be that much of a difference in height.

I would take the load out and see what the difference between the sides are. Usually with the "tundra lean" its only about an inch off at most, you being at about 3 inches is pointing to worn out leafs.

 

The leaf springs were newly installed in 2019, about 15,000 miles ago and saw mild towing in 2020-2021 for about 1,000 miles total.
The rust is 100% thanks to New England winters - it gobbles up everything in no time!
I'll have the load out of there later today and take a couple more measurements. It's definitely far less noticeable without a load.
This particular load is palletized and centered in the bed so I'm pretty confident it's not affecting the lean too much.
Before I installed the 5100's I didn't notice this lean at all. Whenever we towed it was even. When I hooked up the boat for towing after this install is when I first noticed it. I thought it was due to parking on slightly uneven ground but it has since proven to be consistent and not due to uneven ground.
I'm definitely not opposed to it being an issue with the leaf spring on that side but it's strange that it became really visible after installing brand new, more robust shocks.

 

it could have just been a bad install and the shackles are install wrong, or simply a weak spring with a lower rate right out of the box, which would explain why its so much worse under load.

 

Shocks don’t affect ride height, only ride quality. Springs are 100% responsible for supporting the weight of the truck. Assuming the load is even, drivers side springs are the most likely culprit. I’m assuming the springs are a matching set.

 

I'm pretty sure they're a matching set. They were installed just prior to me buying the truck.
I took a quick look at the pallet in the back and it is biased to the drivers side rather than being perfectly centered. Once my kids get home this afternoon I'll have them help me unload the truck and get a better look at it. Unloaded measurements and pics. I know there is some sort of lean going on with it that's pretty pronounced though. It really showed up with the boat attached. I tried finding older pics of the boat hooked up to see if I could see the lean before putting the 5100's on but the only pic I have is it parked unevenly biased to the drivers side...
There still might be stickers on the spring sets too identifying them as a set. I'll look for those as well.

 

they look pretty rusted, that might be hiding a small crack in one of the individual leafs too, its possible.

 

They're definitely pretty rusted under there. Crazy considering I've only had them through two winters so far. I should get under there with a brush to clean them up and see if there's anything noticeable.

I got the load out of the back and it's completely unloaded right now. I took some pics. The forward facing leaf on the drivers side has a visibly smaller gap than the passengers side. Not sure if that could be due to a broken leaf or bad install as mentioned above.
The wheel well gap is far less noticeable with no load.
Also, the leaf sets are these:
Passenger side: https://www.truckspring.com/products/truck-springs/replacement-leaf-spring-90-363.aspx
Drivers side: https://www.truckspring.com/products/truck-springs/replacement-leaf-spring-90-365.aspx

Drivers side gap unloaded


Passengers side gap unloaded


Drivers side leaf spring rear of axle


Drivers side leaf spring forward of axle ** This is the one with the noticeably smaller gap. It looks like it doesn't bend down like all the other lower pieces do.


Passengers side leaf spring rear of axle


Passengers side leaf spring forward of axle



If I can't find a crack after cleaning them, I guess it'll remain a mystery. Maybe it got overstressed at some point while towing and I didn't realize it? Or it could be a bad leaf set as mentioned above and I didn't notice that. For whatever reason, it seemed to be very obvious after I installed the 5100's. I never saw it before then and we towed more at that time than we do now.