Rear Driver Side Sag

Never been in this situation before so I'm wondering what y'all thoughts on this. My 2016 Tacoma has a 3-inch sag on the driver's side compared to the passenger's side in the back. Another important piece of info is there are 1-inch lift blocks in the back. Talked to some mechanic friends and they said most likely the rear shock is busted. But my truck is still under the dealership's warranty so it should be covered (if I take the rear lift blocks off). But I've taken it into service with the lift blocks before so.... I've got a few questions and need some help.
1. If I replace 1 shock do I have to replace both as a pair.
2. Does the dealership document mods to the truck (because I know the lift blocks void warranty)
3. Don't have the original U-bolts used so will they see aftermarket U-bolts and automatically void warranty.
4. Anyone else has any thoughts on what could be broken. I've been told that the leaf springs would be obviously broken if it was that. And visually everything looks fine.
5. Would it be worth just upgrading to better shocks or replacing the ones I got. Haven't checked prices on the stock ones. (also it's 2wd so shock upgrades might be dumb)

 

What you were experiencing is a very common problem if you research the Tacoma lean you will find more information than you would ever care to read so allow me to summarize:

1 when replacing shocks you should always replace both as a pair, they both have the same mileage on them they both have the same wear that said however the shock is not your problem shocks have no impact on ride height. Ride height is determined purely by your springs.

1 a. The SAG is caused by the heaviest components of the vehicle all being in line on the left hand driver's side, the battery the driver and the gas tank all of those weights constantly cycling up and down eventually wear out the leaf spring as the leaf spring is just not quite beefy enough for the truck.

2 when I worked at a dealership, our text typically did not document any modifications unless it was directly relevant to either a warranty claim or caused a special circumstance for work to be performed such as a lifted or lowered vehicle may need a modified alignment rather than trying to align to factory specs beyond that verbiage being in the ticket it was not documented, and beyond that document being in your file for that particular dealership as your customer notes there is no national database that they could pull from to deny you warranty in the future or at another dealership etc.

3 I highly doubt a technician would be able to tell the difference between an aftermarket and a factory u-bolt unless they were looking for that specific thing exactly. Even then, knowing the vast majority of the wrench monkeys that I've worked with they probably still couldn't tell.

4 the leaf spring is not broken, it's simply exceeded it's preset Arch amount, again because the leaf springs are simply not Stout enough with a high enough spring rate for the weight of the trucks specially on the left side which is what leads to the characteristic Taco lean.

5 again shocks are not your issue here it's your springs, you can contact the dealership and call over the phone to see if you qualify for the warranty TSB springs, but you may not. If you do not I would highly recommend looking into getting an aftermarket set of springs such as OME (not to be confused with OEM) deaver All Pro or similar.

An alternative would be to install an add a leaf spring just to that side.

If you got any further questions just let me know.

 

3" sag!? Holy Carp! Must look like you got a flat tire!

 

You aren’t wrong about the Taco Lean, but he said he’s got a 3-inch sag from driver’s to passenger’s

 

Shocks don't support weight. A blown shock wouldn't cause a 3" sag. In fact, you can remove the shock completely and it wouldn't change the height at that corner. You probably have a broken leaf or something broken in the front/rear hangers. Jack up the truck by the frame so the rear suspension is fully drooped. Remove the tire, and thoroughly inspect the leaf pack.

 

I appreciate the reply, that's a lot of useful info. I read up on the taco lean on here but the most I could find was a 3/4" difference. Mine is closer to 3 1/2". If I replace the leaf springs does that mean I'll have to replace both sides too or is that just for the shocks. Does lift blocks automatically make me not qualify for TSB springs or would I still have to take them off.

 

There's no TSB for springs for 3rd gen as far as I know. @Key-Rei may be referring to the "harsh ride" TSB, which was applicable to 2005-2011 trucks (if I remember correctly) and was superseded by the recall (also applicable to 2005-2011 trucks).

You can replace the leaf pack individually. Shocks should be examined and replaced on-condition (i.e. if it's leaking or provide no damping when cycled on the bench).