06 hemi surging
I have an 06 overland with 97k miles that is acting up. It has a 2 inch lift, 32" tires, bilstein shocks/struts, adco rear sway bar, diablo sport tuned to stock 87 octane, and that's pretty much it.
Recently it has developed an issue. If I am cruising between 35mph and 50mph, the jeep will up shift from 3rd to 4th. At 35mph in 4th it runs around 1000rpm, at 40 it's about 1200rpm, and at 45 it's about 1400 rpm. The problem is, between 1000rpm and 1400rpm, in 4th gear; if I give it some throttle to accelerate it surges badly. The whole truck will shake. Once I get to 1500rpm the shake pretty much goes away.
At first I thought it was a mechanical problem like something off balance or bent, but if I shift to 3rd with no change in speed, the shake goes away. Since there is no speed change when I do this, everything downstream of the trans is rotating at the same rate, so i ruled out shafts, joints, etc.
Just some other notes: mds is off when the shaking occurs, I do not feel the shake until I try to accelerate, if I accelerate aggressively it will downshift to 3rd and there is no problem, and this does not happen on any gear other than 4th.
Does anyone have any ideas or suggestions.
Thanks in advance!
2006 Grand Cherokee Overland, Rough Country 2" Lift, Bilstein HD's, Addco Rear Swaybar.