Help PLEASE! Tacoma "Thud" Caused by "Weak Leaf Spring"?

Yes, I've used search, and read most of the related threads, but I'm in a nightmare with Toyota Corporate and local dealer and need advice. Sorry so long, but this is getting crazy...

2011 crew cab, short bed has been doing the hard brake "thud" on brake release since late 2012. Toyota of Tacoma, WA said, "they all do that, no fix", but documented that I asked for the front diff to be looked at.

Took it in to Brian Easler Toyota of Hendersonville, NC, with same complaint. Same story, but no documentation. Took it back, again, and they have diagnosed a "weak" drivers side leaf spring. Took me under the truck and had me pull down on disconnected springs on both sides. One side does feel softer... Theory is it "loads up" under braking, and releases "THUD" when I take my foot off the brake. I am NOT covered under the recall!

This is where I've entered the Twilight Zone. Dealership estimated $1500 to fix. Got corporate involved, and they offered to pay 75% as goodwill. Came back and said the dealership had established $1748 or so as the "actual price". Sent dealership an authorization code, based on dealerships parts/labor quote.

Dealership is now telling me no three leaf packs exist, and the new replacement cost is "well north of $2000, because of four leaf spring pack requirement". Corporate says their offer will not go above first amount, roughly $1300 on the second $1700 dollar quote. Dealership also keeps telling me it would be "easier if I paid all the money up front and got reimbursed by Toyota" when they have an authorization in hand. Corporate says "DO NOT DO THAT."

Questions:
1) Any evidence a weak (not broken) leaf spring could cause this? Has ANYONE had their THUD cured by a leaf spring change?
2) Any indication the dealership is engaging in an unethical business practice?
3) Would I be better served buying aftermarket parts and installing or having them installed? I want to maintain stock ride height. How difficult is the swap-out? I'm ex USAF mechanic.
4) If I go with #3, what is the best 4-leaf, stock ride height replacement brand?
5) Any other advice? Thanks very much for anyone taking the time to respond!

 

It could be axle wrap causing the thud. But it could also be a number of other things. Don't give in to 2k at the Stealership. Buy some aftermarket leafs and install them yourself for much cheaper. I've heard some members added a leaf and it helped their axle wrap.

 

I guess the 2011 is not in the spring recall? Other options include wheelers 3 leaf progressive pack added to existing pack, wheelers HD packs, General spring HD packs, or watch CL for 4 leaf packs to pop up for sale.

 

2011 is covered under the recall, but they pull your vehicle up by VIN. The recall is driven by the number of clips on your spring pack, or at least that's the way it was explained to me.

Is adding leafs simpler than changing a pack? Loosen the U bolts and clips and slide them in?

 

I would just throw some Dakars in there remove a couple leafs to maintain close to stock height
i definitely wouldn't pay that much for a Toyota leaf pack
If your going to add a leaf IMO it's easier to pull whole pack and you'll need longer center pins

 

If you have one weak leaf spring it will wrap more than the other, causing the whole housing (axle to axle) to tweak and miss-align under acceleration and/or braking....if it is bad enough, it will cause your trucks rear end to skate a bit sideways, you can feel it in your a$$ meter, observe it with your eyes, and definitely notice it by your steering wheel going off center...

How do I know this, I had the same thing happen with mine...severe rear end skating under heavy acceleration, the same when braking hard...easy fix...acceleration is not so bad, but hard braking at speed on the freeway is a very scary and dangerous, the butt meter was on high alert and my adrenaline was flowing when it happened to me, weird how the rear end skated....of course, my unit is many years older, but the same principal applies to any truck or vehicle with leaf springs...

Again, easy fix, there are a couple of things you can do to fix it, best would be new springs...

I fixed mine, completely different truck now...

 

Thanks Bldegle2, that's good stuff. I have zero of the symptoms you describe, and no abnormal tire wear, either. That's actually kind of bad news, though, because now I may have no diagnosis for the original problem, the thud. If I pop for new springs and the problem persists I'm going to highly pissed off.

Does anyone know if Toyota has come to a conclusive determination for this problem? The only other symptom I've left off is the noise the undercarriage makes driving over bumpy paved road surfaces (asphalt to concrete ribbon to brick pedestrian pathway to concrete ribbon back to asphalt). With the windows down I hear a clatter from the underside that sounds like a buckboard wagon.