Hey all, I've been having a concerning problem with my JK recently. For info, it's a 2015 Sahara Unlimited, on 32 inch wheels with the 3.21 gear ratio. Currently at 95000 miles, I had my 100k service at 94k (which felt weirdly simple because they only changed the oil & filter, spark plugs, and intake manifold gasket). So here's the problem. When I take my foot off the brake, the car refuses to roll forward under its own power. Sometimes I can feel it stutter like it's trying to, but there's some sort of mechanical resistance which forces me to press the gas in order to move. I also have been getting dismal MPG. I've been getting 13 mpg highway on mostly flat highways cruising at 75. This time last summer I had a longer commute and would get 18-19mpg cruising at 80-85 for over an hour on steeper graded highways. The brakes are good. I know I need a new front driveshaft, the boot at the rear end of it spews out grease so the aluminum heat shielding in the area is covered in black spray. Could this be the issue? Another thing to note, this particular noise has been around for many months now, but when I roll to nearly a stop, like 1-3 mph, and then hit the gas again to get moving there is a really loud clunking sound from beneath the car that occurs in about 50% of these situations. Has anyone has similar issues? Any ideas what the culprit is?

 

When my 2012 manual trans had a rolling resistance issue, it was a hanging up caliper. I learned which one it was by driving a bit, then feeling the temperature of each rim. The one with the sticking caliper was noticeably hotter. Replaced the caliper and no more rolling resistance.

 

Have you checked your trans fluid level?

 

Te clunk is probably a worn out cv joint or universal on the drive shaft.