2004 Ram 2500 5.9 4x4 48RE

Not a huge fan of these 48re's anymore, lol. Here's the issue.. about 75% of the time when I take off from a stop, the engine will rev slightly, probably 100-200rpm, before I feel any drive engagement, which is a thunk, and then the vehicle takes off. I can tell when it's going to act up if I take my foot off the gas it doesn't really want to creep forward. It will, but very slowly. It shifts great, 1st gear holds great on pulls, 1-2 shift is excellent with no flutter or hesitation. Lockup is solid.

I can't really determine anything that triggers it. Sometimes when I stop at a red light and go there's no issues, other times, more often than not, it'll do that weird rev up and clunk thing.

Ideas? Torque converter? Fluid is fresh, not burnt. Accumulator? Front band is new, but this problem is newer than the band, if that makes sense.

U-joints are all in good shape, no abnormal play in the differential

 

I had that problem in spades with my 98..... (the one in my sig.) At stops, shift lever in Drive, the trans would drop out of gear, and then hit HARD when I stepped on the gas. It got to the point that I stopped going thru drive-thrus, as it was simply too uncomfortable. I bought one of the heavy duty governor stuff kits from Ebay, had a local trans shop install it for me, (along with a fluid and filter change) and the problem vanished. Borg Warner (I think) heavy duty governor pressure solenoid, gp sensor, and output speed sensor.

 

Went with the ATS GM solenoid conversion. Shifts like a dream now. Thanks homie.

 

As I recall, the GM system was self cleaning as well.

 

Do you think I should go this same route? I have a 05 4x4 2500 5.7 though so not sure if it has same transmission. My symptoms are slightly different where after sitting off when starting and moving into gear it will take 2-4 seconds before moving. No thump sound or feel though. Also the other day it was feeling a little slow going 40 up a slight hill and when I pressed the throttle in so it would shift and accelerate it jumped up in RPMs like normal but speed stayed the same.

FYI: Prior to 4 years ago I had never even changed my own oil but I’ve done a lot more than that since then still though I’m a novice and only barely pretending like I know what’s going on.

 

I would expect you do NOT have the same trans, so, no, I don't think that would work for you.....
The slight delay going into gear at first start is likely just the torque converter getting refilled..... (I don't think it charges the t/c in park..... but, don't know that for sure.) I think in your case, first thing I would do, is check fluid level.... If it hasn't been changed in a while, might be time for that as well.

 

I really appreciate the reply. So since I’ve had it, about 4-5 years and 40,000 miles, I’ve constantly checked the transmission fluid just by pulling the dipstick and it’s always the same level and always looks practically new with that bright translucent red color. I’ve compared to fresh because I have a leak in my power steering pump area and they both take the same fluid.

I’m not sure if that’s a good enough test and I likely should just replace it with fresh fluid you think? With how many miles I’ve put on it and not knowing when the fluid was replaced before I had it exactly. Especially since I tow almost every day. Not far but I do tree work locally so i definitely put the truck to work.

 

Yup yup. I did tree work as a sideline with a buddy of mine for a while. Some of that equipment is NOT light. It was fun, but, I just don't have the health for that kind of behavior any more.

If you don't know the last time it was changed, then it is highly likely long passed time for it to happen.....