Hello, new to this forum... I have a 99 Durango SLT 5.9L 4x4, 108K
Problem #1: ABS Light on, Brake light on, check engine light on, Oil pressure drops to zero then comes back, and speedo doesn't register until I hit 20mph. All this happened around the same time. I have read on other sites that these issuesmay all be related to a faultyrear diff sensor or something like that, is this true or are they separate probs?

Problem #3: trans gear will not upshift out of first. I had lower tranny rebuild at shop 13 months ago (just out of warranty) for same problem. Why does this keep happening and what can I do to fix it?

Problem #2:when cold, the engine or rad fan seems to "roar" and I have lack of power until I get up momentum, then power seems to "kick in" and engine quiets down. I've had this problem ever since I bought it (used at 50K miles) At first, I thought this might be flywheel prob but now I think maybe fan clutch? Is this normal? I've heard other D's do it too...

Sorry no signature or pics yet... Thks in advance.

 

Rear speed sensor as suggested for abs and speedo issue. Get your CEL pulled at auto zone and let us know about that. The CEL is probably on for your #3 issue, maybe a governor issue? The roaring fan clutch is pretty normal for a hd clutch mine did it too after I changed my fan clutch, it annoyed me so much I made the switch to an e-fan.

 

umm problem #3 could be a bad output sensor on the tranny(it is underneath on the drivers side), my old truck wouldnt shift out of first till 3000+ rpms and that was the problem, but pull the CEL codes and ill let you know for sure, and the roaring fan is normal, all of our trucks do it, and did it from brand new dont worry about it

and #1 is a rear wheel speed sensor on top of the diff, just replace it

 

Thanks for the posts, I have a code reader, last time the CEL came on it was the tranny. Haven't checked the code yet this time, I'll check it tomorrow and post back the info. I appreciate the feedback. Regarding the oil gauge issue, I bought a new sending unit - thinking that might be it because I have a minor oil leak in the area (hopefully not rear main). How hard is it going to be to get to the top rear of the block to pull the sending unit? (I have the socket bit)

P.S. - what do I have to do to earn rank around here? Is that "backseat driver" stuff in my profile preferences somewhere? -lol

 

I would definitely replace both sensors, one on the tranny and one on the rear axle. Should address both #1 and #3 of your problems.

#2 is your fan clutch. This is normal. Don't ask me why the stupid clutch likes to stay in locked position from cold start and then release when the engine warms up. Just that most aftermarket clutches may be a heavier duty grade vs OEM so you hear the fan roar more often. But the fan clutch should slowly break in over time if it is brand new.

 

you gain rank("backseat driver") from making posts, after every so many posts you get a new title

 

Update - just finished a radiator swap in the car (unrelated) and replaced the output speed sensor on the overdrive housing. The front sensor did not solve anyproblems, butI'll put the rear differential speed sensor on tomorrow and read the CEL code and post back.

Note to Shrpshtr- I really like your "Piratey" avatar... lol. Where'd ya get it?

 

someone i wa stalking to in OT found it and gave it to me when i asked for one that was themed along the thread we were it,(no it wasnt pirates)

 

Okay, here's the latest: I installed both sensors (output sensor on overdrive housing and rear diff wheel speed sensor), and all my problems are solved EXCEPT the shifting problem (see Problem #3 above). After rear diff sensor install, the ABS and BRAKE lights went out, and my oil gauge has stayed at 40+ pressure. THANKS SO MUCH for the help. Now if anyone could tell me what else it could be with my shifting issue, I would be grateful. Here are the details: OBD2 Code is P1756. Tranny will not shif out of first gear without help - I have to get up to 30mph (tach goes to 4500rpm), then manually shift to neutral, let the tach drop below 2000rpm, then back to drive while the car is moving, then -hopefully- it will shift into second. Same thing with second, except up to 40 mph, tach goes up to 3500rpm, then shift to neutral and back into drive. If I can get to third gear, everything is okay from there, including overdrive. Any ideas???

 

hmm, idk the sensor on the tranny was the problem when my dak went out like that so i really dont know, but i will tell you that google is your friend