So I finally added my 5.13 gears to my jk and I did all the break in stuff change out oil and drove a little towards home which have to go through mountains. Is it normal when I'm driving up a steep hill I'm at around 70mph and all of a sudden it's like I loose all power with foot on pedal still and end up around 55mph before I get to flat ground or down hill then back to normal unless I step in has and shoot up too about 3000 rpm. Is that normal and ok to do? Do I leave OD on? Turned it off once and didn't see much improvement. Any tips please

 

do you have a 6spd or auto?

 

I'm guessing auto since he mentioned he turned OD off.

 

I have a auto

 

I wouldn't be doing 70 mph with new gears. Keep it down till you get 500 or so miles on it.

 

Is it safe to assume you reprogramed for the new ratio and tire diameter?

 

I posted this earlier and never was able to get a answer. It was always questions or others talking back and forth and that don't help me. Anyways. I have a 08 jk auto 4 dr. I added 5.13 gears and yes I have broke them in by 500 miles and changed out oil. I do have a superchip and programmed my gears and tire size but for some reason when I was driving home the other day thru the mountains and happens here on hills. When I go up hills my speed decreases and will settle around 50-55 even if I have the pedal wear I normally go 70 at. Unless I push down the pedal and get my rpm to 3000 with OD on. I try turning OD off but still no difference really. Is this normal? Or what should I do or recommendations?

 

I'm not trying to be cute. Seriously, what were you expecting. This sounds normal to me. When you increase the load on the engine ( hill or trailer ) you have to mash on the skinny pedal a little harder. Your RPM's will go up. And your speed will go down.

 

That is normal. The position you have the pedal on level ground and doing a rate of speed at 70 mph, and when you start going up a hill you are asking more of your engine and you are increasing the work required of the engine to go up the hill. So if you keep the pedal at the same spot and increase it's workload you will lose speed from the gap from power to work ratio flat vs hill. So to keep this from being a problem either build up more speed prior to hitting the hill, or once you hit the hill you have to press the pedal farther down increasing gas being used and having the power output i.e. gas being used to match the new increased load of the hill.