Transmission problem - Automatic - 2008 JK
JK Enthusiast
Joined: Oct 2010
Posts: 101
Likes: 0
From: Leesville, LA
1. -- Condition: 50 mph, 3rd gear, o/d on, 2100 rpm:
-- Problem: Accelerating, especially going slightly uphill. When I press the accelerator, the rpms, rather than rising, drop to 1200 rpm, bogging the truck down. To accelerate the throttle must be mashed almost to the floor. The transmission then occasionally downshifts to 2nd at 55 mph, showing 5,500 to 6,000 rpm on the tach. Trying to accelerate into traffic on a freeway access ramp is terrifying. At times the only way I get the truck moving is to reach down and turn off the o/d almost like a manual shift.
-- Problem: Accelerating, especially going slightly uphill. When I press the accelerator, the rpms, rather than rising, drop to 1200 rpm, bogging the truck down. To accelerate the throttle must be mashed almost to the floor. The transmission then occasionally downshifts to 2nd at 55 mph, showing 5,500 to 6,000 rpm on the tach. Trying to accelerate into traffic on a freeway access ramp is terrifying. At times the only way I get the truck moving is to reach down and turn off the o/d almost like a manual shift.
Just in case there are others with O-8 crappy trans syndrome.. I've observed that if I just tap the gas instead of shoving it through the floor, it shifts down 1 gear instead of 2 ("2nd at 55mph"). It's still strange that it bogs down going up hill tho. I can live with the weak motor, trans is an aggravation. 
JK Enthusiast
Joined: Jul 2010
Posts: 198
Likes: 0
From: Blue Springs, MO
Holy Thread Revive!! Just in case there are others with O-8 crappy trans syndrome.. I've observed that if I just tap the gas instead of shoving it through the floor, it shifts down 1 gear instead of 2 ("2nd at 55mph"). It's still strange that it bogs down going up hill tho. I can live with the weak motor, trans is an aggravation.
Just in case there are others with O-8 crappy trans syndrome.. I've observed that if I just tap the gas instead of shoving it through the floor, it shifts down 1 gear instead of 2 ("2nd at 55mph"). It's still strange that it bogs down going up hill tho. I can live with the weak motor, trans is an aggravation. 
JK Junkie
Joined: Oct 2007
Posts: 2,565
Likes: 0
From: HAWAII
I didn't have any complaints with the 3.8, I just didn't like the auto trans behavior...That prompted me to get the 2012 once I knew the auto trans has been changed. The 3.6l is just the gravy on the side...
JK Enthusiast
Joined: Dec 2009
Posts: 138
Likes: 0
From: Marquette, MI
Had the same problem... Here is my fix with 33's I went to 538 gears and bought the superchips tuner and installed a custom trans tune, this has made the jeep a driver again, stays in gears 1 2 3 until 2500 3000 rpm's holds gears longer until I hit the top of hills and downshifts with just a slight touch of pedal... Made the jeep enjoyable
But I agree, this my 4th wrangler first and LAST automatic, if Bantam though a jeep needed an auto it would of made it that way.... Silly me
But I agree, this my 4th wrangler first and LAST automatic, if Bantam though a jeep needed an auto it would of made it that way.... Silly me
JK Enthusiast
Joined: Oct 2010
Posts: 101
Likes: 0
From: Leesville, LA
Had the same problem... Here is my fix with 33's I went to 538 gears and bought the superchips tuner and installed a custom trans tune, this has made the jeep a driver again, stays in gears 1 2 3 until 2500 3000 rpm's holds gears longer until I hit the top of hills and downshifts with just a slight touch of pedal... Made the jeep enjoyable
But I agree, this my 4th wrangler first and LAST automatic, if Bantam though a jeep needed an auto it would of made it that way.... Silly me
But I agree, this my 4th wrangler first and LAST automatic, if Bantam though a jeep needed an auto it would of made it that way.... Silly me
JK Enthusiast
Joined: Dec 2009
Posts: 138
Likes: 0
From: Marquette, MI
Yea the SC is well worth it... Takes a lot of patience and research I had a TON of help from a fellow forum member Jpopp, without him I would not of grasped what was going on with the custom trans tune parameters. I have 285/70r17's I had originally changed gears to 4.88s pulled a a small 1500lbs trailer out west absolutely hated the gearing and trans combo (without the SC trans tune) so I went big! bought a Dynatrac d44 and swapped the 538s. It made pulling the trailer as easy as pie flat stretches I could use OD again but still struggled holding gears / downshifts on any inclines. The SC trans tune fixed it... The 42r trans still has poor gear arrangements, but the SC makes it much better to manage... Gas mileage is consistently around 13-15 city and 15-18 hwy.... I would recommend the bigger gears 513s if ya have the d30 front you will like them much better and it make help keep your engine from lugging and potentially overheating the transmission.
I'm on a mission right now to do EVERYTHING humanly possible to prevent my investment and pride from going up in smoke... Mech fan project, factory trans cooler, extra capacity cooling finned trans pan, temp gauges.... So... Keeping my fingers crossed!!
I'm on a mission right now to do EVERYTHING humanly possible to prevent my investment and pride from going up in smoke... Mech fan project, factory trans cooler, extra capacity cooling finned trans pan, temp gauges.... So... Keeping my fingers crossed!!
