Hello all, first post.

the truck:
2001 Dodge Ram 1500 5.9 SLT 200,000ish mils (larger tires installed so milage is off.)
known "Mods":
short cold air intake with filter box. 6" lift with 4-link on front, and spring rear.
Current repairs:
TPS, spark plugs, spark plug wires, drive shaft, new trans with apx <15k miles.

So, I've searched around the forms looking for similar issues but not able to find anything I feel that is close enough. Unfortunately, "sometimes" is kind of the key word in my trucks story as their seems to be little rhyme or reason to when it happens.
While driver at speeds around 45-55 MPH, RPMs hanging around 1,300ish depending on speed, temp is around 180*s, outside temp in the 30s in the morning and 70s in the afternoon/evening. The issue or "bucking" will happen morning and evenings. it feels like at just hit a pothole or as if I've been hit from behind in a slow crash. in otherwards its quite jarring. RPMs sometimes jump up about 500 RPMs other times no RPM change. Sometimes the tranny will shift down out of OD in to drive and hold for approximately 5 to 20 seconds then it will shift back to OD and it's all good like nothing is wrong for the rest of the drive (10-20 minutes).

Other notable oddities possibly related?
Say I set the cruse at 60Mph and I'm climbing a slight hill or steep hill in OD, the truck will not shift out of OD to drive till it hits speeds around 45Mph.
The 4x4 Module in the front axle (at least that what I think it is) will make this noise "Brrrrrr" (kinda like the sound an A10 warthog makes) if I hit a good bump "sometimes" it wont do this for weeks or it will do 3 times in a day. I can usually get it to stop if I give the 4x4 shifting **** a little push past the 2H position. Note I do not use the 4x4 in the truck at all, its almost always in 2H. I've used the 4x4 in the truck one time last year, actually, July 4th 2023 lol.

Thanks everyone in advanced for stopping by and reading my post.

 

Did this problem start before, or after the trans was changed?

 

Are you aware of the plenum issues? The "bucking" could be caused by a leaking plenum gasket. The "grrrr" sounds like the cad on the front axle is trying to engage. Check the vacuum at the cad, There is two vac lines going to it. One is 4WD the other is 2.

 

This issue started after the transmission swap. also add to that it started something like 15k miles after install.

 

Awesome I'll take a look at these 2 points of interest, and I have not heard about the plenum thing, I'll find a thread on the Plenum issue.

 

Just a quick update about this drive to work. I have about a 30-minute drive to work. around the halfway mark the "bucking" started. The truck was, what I would call "franticly shifting" up and down. RPMs started Jumping to around 2k and up to 2.5k then down to 1.5k looked like it was seeking the proper gear. It was shifting from OD, Drive and possibly 3rd? all this was preceded with the bucking then the frantic shifting.

 

Check engine lite on?? If it wasn't doing that before the trans work, I'd be havin' a chat with your trans guy. The crank position sensor is frequently a victim of trans swaps.....

 

So if you pull it into 2nd when occurring do the problems vanish?

Some of your symptoms make me think misfire as the 5.9 V8 will buck violently when misfiring, almost like REALLY severe wasboard. But other symptoms sound like trans really is hunting for gears.

 

Good call ..... I'm kinda thinking the same thing ..... First thought is transmission, but if it is misfiring and losing power .... then the transmission would be confused as to what gear it should be in?

If it is misfiring, seems like there would be a code of some sort to give a clue.

 

I've been looking around at the crank sensors, just in case. I found some MOPAR from dodge and a Delphi with O'rellis, Not sure how picky she is with aftermarket. as for codes, I had a P1391 pop up then I did the TPS then it poofed gone. ATM no codes to pull.
I've dropped it out of OD while driving in to drive but seams to make no change, have not tried 2nd as I'm usually moving around 50ish, not sure how the trans would like that gear change to 2nd. kind of a chicken to try.
As for misfires, I changed out all plugs and wires (NKG iridium and NKG wires) just in case of that, but it could also be the dist-cap too I suppose.
Could the output speed sensor on cause the hunting issue? or possibly these misfires make it shift down and ack all odd?