3rd gen front struts on 2nd gen

I know your question is a little old but im here to answer.

Like most have stated, the 3rd gen coils will give an inch of lift.

5100's 2nd and 3rd gen part number have the same distance from the center of the bottom shock eye to the lowest "0" lift spring seat clip. This is to say you can use either the 2nd or 3rd gen 5100 part number interchangeably between 2nd and 3rd gen trucks. And use whatever coil you want to achieve lift.

Now with that stated, there are some dimensional differences with fully extended vs fully collapsed lengths between the 2nd and 3rd gen 5100 part number. The 2nd gen part number has ~ 0.3in more extension and ~0.55in shorter collapsed length for ~0.85in of total shock travel MORE than the 3rd gen part number. The slightly less extended length of the 3rd gen 5100 part number is a sound move as the 2nd gen 5100 allowed for too much droop and the stock UCA had a tendency to hit coil depending on rotation, by limiting droop SLIGHTLY with the 3rd gen 5100 a stock UCA on a 2nd or 3rd gen truck wont hit coil.

As far as the longer collapsed length of the 3rd gen 5100, its a non issue as you were left with ~ .75in of extra unused travel on the 2nd gen part number at full compression with stock bumpstops. The ONLY time this could become an issue would be with the use of spacers to lift the truck... but why not just use the clip settings.

There are also more finer clip settings on the 3rd gen 5100's. You can correct taco lean very easily by simply moving the driver side up one from whatever setting you have on the passenger, 2nd gen shocks there would be too much of a difference to do this.

Lastly the 2nd and 3rd gen shock bodies are definitely different. The 3rd gen body is LONGER (hence longer collapsed length) but there is some extra going on in there for sure as they do not top out nearly as hard as the 2nd gen part number.


Needless to say after a bunch of research I ended up with some 3rd gen TRD OR coils on the 3rd gen 5100 part number on the front of my 2nd gen for reasons mentioned above set at 0. The ride is AMAZING.

 

I do have the 2nd gen 5100s. If i understand correctly, overcolapsing is not an issue with bumpstops. As for this truck it is highly unlikely it will ever see full droop. When i was installing, with with suspension freely hanging, I did not observe the uca contacting coil. Maybe it needs the full weight of wheel and tire? However when istalling 3rd gen spring on to the 5100s. I did notice that even on the second from the bottom clip setting, the spring compressor had to be let out a lot futher to engage the top and bottom plates as compared to factory shock. According to the instructions the second setting on stock coil should net roughly .83 of an inch, and then an inch from 3rd gen coil. I completely overlooked the fact that the coil was a take off from a 3rd gen crew cab. We ended up with just over 2 inches in the front. My report though after a couple of drives is that the truck rides and drives very good. A vast improvement over factory. It soaks up potholes well and has nearly no body roll (in the front anyway). If im being honest I ended ordering the parts from Amazon. Was the best price and free ship with prime. Same goes for the icon progressive aal, it was on sale for $167. I ordered it knowing if i didn't use it i could just take it back to khols lol. I may go ahead and use it the truck does have a camper shell that may see use.

 

When i had the 2nd and 3rd gen coil assemblies side by side they were the exact same length. The 5100s were quite a bit longer than either. The 3rd gen coils did have at least one more wrap than the 2nd gen coils. As stated im previous post when decompressing the springs onto the 5100s, I had let the spring out a lot further than my origional starting point to engage the top and bottom plate to get the compressor off of the spring. I hope that makes sense.