r1volta Posted October 15, 2015 Share Posted October 15, 2015 1990 4.0 automatic has no power in drive but runs fine in reverse Link to comment Share on other sites More sharing options...
gogmorgo Posted October 15, 2015 Share Posted October 15, 2015 Not much to go on. Does it not move, or does it just struggle to do so? When was the last time you checked the trans fluid? Have you tried unplugging the trans computer to shift manually? Link to comment Share on other sites More sharing options...
cruiser54 Posted October 15, 2015 Share Posted October 15, 2015 Not much to go on. Does it not move, or does it just struggle to do so? When was the last time you checked the trans fluid? Have you tried unplugging the trans computer to shift manually? Agreed. Could be a blown/corroded fuse to the TCU. Link to comment Share on other sites More sharing options...
Eagle Posted October 15, 2015 Share Posted October 15, 2015 Does it run if you shift manually to "Lo"? Link to comment Share on other sites More sharing options...
cruiser54 Posted October 16, 2015 Share Posted October 16, 2015 Well, it appears that we care more about fixing his Jeep than he does............. Link to comment Share on other sites More sharing options...
r1volta Posted October 16, 2015 Author Share Posted October 16, 2015 Sorry for no responses to the help. Jeep is in Oregon, I am in Mass. Work schedules and time difference will delay any work until weekends Link to comment Share on other sites More sharing options...
r1volta Posted October 16, 2015 Author Share Posted October 16, 2015 Trans fluid is clean and full All grounds removed and cleaned Have not tried driving in low because the engine is now running very rough I am waiting on results of fuel pressure test EGR is clean and working Plugs are new Link to comment Share on other sites More sharing options...
cruiser54 Posted October 16, 2015 Share Posted October 16, 2015 Are your engine to trans bolts loose or missing? CPS harness routed properly? Link to comment Share on other sites More sharing options...
Eagle Posted October 16, 2015 Share Posted October 16, 2015 To check the tranny, the FSM instructs us to remove the TCU fuse and shift manually. When driven that way you lose one of the two low gears when in the "Lo" position -- second gear, IIRC -- but otherwise you should be able to drive it by shifting manually. This is to diagnose whether the problem is a transmission problem or a TCU problem. You also want to be sure the shift linkage is properly adjusted. That's why I asked if it runs in the "Lo" position. Link to comment Share on other sites More sharing options...
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