I just bought a 2000 Durango vin 1B4HR28Y3YF234427 , The vehicle has 157k on it. Starts and runs great. I have no reverse though. I was searching the internet and found info saying this has a 45RFE tranny, but I'm not sure after reading hundreds of other posts and everyone is talking about a 44RE instead. This was an accident vehicle, the passenger airbag had deployed it looks like, it shows two codes on my OBD2 scanner, an ambient temp sensor near battery is low voltage input, I think the sensor is missing, and an auto shutdown circuit fault, but it still runs and goes into drive. it does just die sometimes out of the blue after warming up, I think that's just a throttle body sensor issue I may have fixed it already simply by unplugging and plugging them back in. Drive seems to work fine, it was a quart low on tranny fluid but I can see where the cooler lines are not positioned right near the radiator. Probably a new radiator. The RPMs do not react at all when shifting into reverse, just like neutral. Anyone have any ideas? or good correct info? I will try a vin search and see what comes up on tranny and engine, all I see in the engine bay is magnum, no size, lol

 

I don't know about the issues you're having, but you should have a sticker somewhere under the hood that tells you. 4.7/545RFE 5.2/44RE 5.9/46RE

I think all 4.7s in the 1st gen durangos had 545RFE in them. The 5.2 and 5.9 look the same when you open the hood, 4.7 is completely different.

 

Its a 5.2, I ran the vin number. I have found out since posting this that the info I had seen online was wrong in saying it was a 45RFE. It is the 44RE. Now to fix this reverse problem or see if its worth fixing.

 

2000 is a unique year as all 3 v8s were available, the 5.2 was only available on 2wd models and the 4.7 only on 4wd models, the 4.7 came attached to the 45rfe from 2000-2002 and 545rfe from 2002-2003, the only difference between the 45 and 545 is the programming that controls them (just FYI)

that said the symptoms you are describing are pretty common on poorly maintained 42/44/46re transmissions, and the solution is usually to rebuild the trans as the parts that make reverse engage are wore out or broken.