I have a 1998 Durango 5.2 4x4, with auto tranny. I have been working on it for a couple of weeks now trying to fix somethings up because I don't want to buy another vehicle (BTW is has 215K miles). The original reason I started the project was because I lost reverse and the AC wasn't working (At least good). I want to start with the transmission but I believe that the couple of issues here are related. My transmission lost reverse and was shifting like crap, lost basically all horsepower, lost first gear, and it was flaring (RPMS hitting 4000 to shift) badly between each gear.

So I bought a remanufactured transmission from Mopar transmissions. I took the transfer case to a shop had them do a seal job, dumped the fluid out of the front and rear diffs and refilled, changed all U-Joints. (I haven't got to suspension yet) I did many other things while I was inside, such as replaced oil pump, oil pump gasket, rear main seal, timing cover gaskets, installed high performance water pump new fan clutch, flushed cooling system, new power steering pump, replaced trans cooler lines and added a a tranny cooler. AC: replaced compressor, condensor, dryer, expansion valve, evaporator core, heater core, blower motor resister, blower motor, and so forth. Basically, my new transmission works well, but it still flares between shifts and I am still suffering from horsepower loss. My idle seems like it is too low and like I am having some sort of idle control problem so I replaced the TPS and adjusted the TV cable but I am still not solving the problem. On top of this my engine is still getting hot at idle with AC on. At idle without the AC on my RPMS are about 650 when I turn the AC on though it goes down to about 500. So I am thinking that the transmission flaring and the AC running the engine over 210 at idle is related. I personally think that when the AC is on the engine should idle at about 900, but still I am stumped. Any other suggestions are appreciated before I just go ahead and take it to the shop. There are no codes either.

Thanks for any responses!!

Also let me know if its too confusing and you need more information. I know that I did a lot of stuff. Long story short, I replaced the entire cooling system AC system and transmission and rebuilt most of the drive train with the exception of rebuilding the motor.

John

 

your idle rpms seem backwards to me, im used to seeing idles around 500 (-600)w/o the a/c and around 700 or so with it.

how have you replaced the IAC? is the cooling system full? is the clutch fan working properly? you SHOULD hear it engage when the engine starts to overheat (spin it by hand w/ the engine off, more than 1/2 a turn replace the clutch)

think thats it for now, ill add anything as i think of it

 

I thought the same thing. Shouldn't it idle higher when the AC kicks on? Fan clutch is brand new. I replaced the entire cooling system. I haven't touched the IAC though. The AC system is sitting at 25-40 on low side and 225 on high every part was also replaced on it. Are you thinking IAC sensor? The od thing is that whatever the problem is, is affecting the tranny too and the thing is not giving any codes. I was kind of thinking maybe computer too.

 

im leaning toward the iac being the culprit but thats jmo and the tps is on trial yet too, but id do the iac fist

 

replaced tps the other day cleaned throttle body and replaced IAC today. Still doing all same problems. I am wondering if I am having computer problems.

 

I'll be damned. I didn't know this thing throws codes without turning on the check engine light. I just scanned it and got p0751, its a transmission problem. Now its going to the dodge house Still doesn't explain all of my idle issues. Thanks for the help!!

 

I wonder if the 99 Durangos throws codes without any dummy lights lighting up?

 

some minor codes do get thrown w/o the light going off, but chances are they wont be related to your noticeable problems (they might be, but usually a code w/o the light wont be for something to affect the way it runs/drives)