Rick in Colorado

My 2012 is in town, on the railcar, and I have an AEV 3.5" lift, Pintlers, and 35" km2s waiting for it. Unfortunately, I got caught in the early order, "I thought that autos always came with 3.73s" snafu. When I drive it, I'm afraid that the 3.21s are not going to cut it, but the lighter 2-door Sport body may help. [This is a daily driver; snow vehicle only.] My install guy spoke with Dave at AEV and while he (install guy) usually recommends 5.13s for 3.8 liter 4-speed autos, he is between 4.56 and 4.88 given the new 3.6 with 5-speed auto. I don't think that the 3.73 would have cut it with 35"ers.

Any thoughts? Obviously, I'm going to drive it for a while before deciding.

Sprocket

Great question.. Hope to get some good answers.

dp7197

From the AEV Forum:

Here we go. It doesn't matter how much more power the 3.6 has, it has to do with the trans ratios. Even the 5.7 and 6.1s needed 4.88s with 35s because of the tall ratios of the 545.

The A580 auto is geared lower throughout its range. Whats this mean? It means that 4.11s with the A580 is equivalent to 488 with the 42RLE. So 4.11 is ideal for 35s.

I'm pretty sure I'm the only person on this board who has driven a 3.6 A580 with 35s and 4.10.

The 3.6 does not require the same ratios as the 07-10 JKs, which is good because the pinion gears are that much stronger. 4.88 would be fine for 37s.

dh


Sounds like Dave Harrington is fine with the lower auto ratios, 35s, and 4.10s. Hope this helps.