I'm looking for some help in troubleshooting a recent acquisition from a family friend.

The truck is a 2001 Dodge Dakota 4.7L with the 45RFE and 4x4.

Truck was driving along fine in 2H down the road then apparently acted like it went into neutral.

Truck was towed to their home where it has sat for a few months before it was given to me and battery died so could not retrieve any codes.

I did some preliminary reading and had the truck towed to my place and replaced both filters and refilled with fresh ATF +4 fluid idling in neutral to the appropriate level.

Unfortunately this did not magically correct the issues, I had seen some posts where the spin on filter was causing issues for individuals. The fluid was reasonably clean but did have some material in the oil but suspect it had not been serviced in several years. No codes from the attempts to move it in/out of the garage yet either which is odd, my other Dakota is all to happy to throw codes at me to start with.

I'm wondering what to do next. Truck does not roll in Park so the T-case must be fine though it does not show a light in 2H or 4H or 4L when attempting to move the **** inside truck. My reading tells me this is a separate issue that requires troubleshooting the TCM under the dash. I have not had the truck up in the air to test if it's locking 4x4 via the driveshafts yet.

At this point, the truck does nothing in reverse or forward gears but Park does work to prevent the vehicle from rolling.

I have had numerous Dodge/Chrysler vehicles over the years and am mechanically inclined, hoping for some insight on this truck as my other Dakota is an 5.9 R/T so the driveline in this 4x4 is all new to me!

 

Sounds like the front transmission pump failed. There are some solenoids in it that earlier transmissions didn't have. I'm not really a transmission person. I can put them in but I don't want to pull one apart. I think the best bet would be to put another unit in it and flush the cooling lines really well to get any junk out of it.

 

Thanks for the reply!

I'm leery of replacing the transmission til I can validate exactly what has failed.

It seems there is a fair amount of electronics in the 45RFE compared to my other truck.

I understand the TCM can be a frequent culprit for 4x4 issues(likely experiencing on this truck) and am wondering if it is also possibly the culprit with this truck.

Are there any good troubleshooting guides written for this transmission I can reference? I have downloaded the 2001 FSM but the information within is more aimed at dissasembly/assembly than troubleshooting unfortunately.

 

There should be two modules. The Transmission Control Module (TCM) and TransferCase Control Module (TCCM).

And yes, the FSM is more related to teardown/rebuild because that is what the dealerships do. They typically don't guess. They have tools that can read errors hidden inside the sub-modules (called U-Code DTCs). Your best bet will be finding somebody with a DRB3, MT2500, Mongoose, or other similar device that can read U-codes.

 

Thanks magnethead!

I guess I am too old fashioned thinking I could use my Autel code reader to get some deeper codes but the truck isn't even throwing a generic P0700 so it wasn't of much use other than looking at some live data.

I will see if I can find someone with a DRB3 in Calgary AB so I can pinpoint the issue instead of throwing parts at it.

 

Well I’ve been steadily working on the truck and finally got it buttoned up last night with a Jeep WJ transmission and matched TCM.

On the very first drive though the truck makes a horrible bearing noise from the 9.25” rear end. Went home and ran it up on jack stands and it appears to be coming from pinion bearings.

Truck didn’t have the issue when trans died 18 months ago and it was parked.

I’ve been through the FSM and these differentials are rather unique with their design compared to Ford 8.8s I’m familiar with.

Is the pinion bearings a common issue on these trucks? I’m debating the $s to do the bearings versus purchasing a JY unit.

If replacing the entire 9.25 axle, is there a better one out there or a model year that is an improvement?

 

I think the newer ones had rear disk brakes? Maybe a limited slip instead of the open rear? The 9.25 is generally pretty reliable..... Just sitting shouldn't have done anything to it, unless the fluid was contaminated??

 

I don't know how many miles you have on your truck, or whether it was cared for. It sounds to me like it didn't receive the best of care prior to your acquisition of it and that will naturally affect reliability. If it's any reassurance, the 4.7 with 545RFE transmission and 9.25 rear end, are usually extremely reliable with the most basic of care. I'm proof of it as I drive mine daily and there are many Dakota and Durangos running around with almost half a million miles or more on the clock.

With the 4.7, basic care means don't overheat it, don't run it low on oil and make sure you run full synthetic oil. With the transmission, I suggest installing an oil drain plug in it next time you drop the pan so having to drop the pan each time doesn't kill your incentive. Change the filters, then drain it every 25-30K after that. With the rear end, I drain and fill every 50K, pulling the rubber plug to check it once a year. A 4x4 will probably need it fluid changes more often though. I wish you best of luck in getting it to where you want it.

 

Thanks for all of the comments!

The truck was run on a fairly modest budget by a friend of the family and has 217k Kms on it now.

I drove the truck a few weeks before it died around the block, not far enough to get much of a feel for it but enough that when it became available I decided it was worth the effort as it ran/drove fine, had new brakes and new tires.

Aside from the diff noise, it runs down the road excellent and have grown quite fond of the extra room with the quad cab compared to my R/T.

I appreciate the education and expertise, if the 9.25 was a problematic axle I was not going to search out one from the junkyard but if they are reliable this one simply fell victim to deferred maintenance a replacement JY axle will be a vastly cheaper alternative to getting the truck back on the road.

I did add a drain plug when doing the trans swap as I plan to drop the fluid again in the trans at the next oil change. While the doors are a little rusty on this truck(hence the username) it is a great runner and where I live and work the 4x4 is a necessity.

Looks like I will be on the prowl in the JY for a 9.25" 3.55 LSD from a newer truck to upgrade to discs while i'm at it. I'm imagining the associated brackets for the newer axle should be bolt up as well to maintain my parking brake as well as the potentially different body to softline for the axle? I will take some pics of mine before I head to the yard tomorrow to start scouting.

Many thanks!

 

I pulled a 9.25" 3.55 LSD axle this morning at the junkyard with a friend from a 2 wheel drive truck.

Unfortunately when we got home we discovered the difference between a 2wd(spring under) and 4wd(spring over).

We are debating rewelding the perches but what a frustrating experience as we were not aware of the differences.

Hopefully reading this saves someone from this hassle in the future! This truck is really making me work to get it back on the road!!