Hello, I recently purchased a 2005 Dodge Ram 1500 quad cab with the 5.7 and has 74,xxx miles. I've noticed that when I am driving and going anywhere from 60-65mph, there will suddenly be a "clunk" as if the transmission slipped. I say it as a transmission problem, but I'm not sure if it is. Just had the transmission serviced, they shop thought everything looked great! Truck shifts through gears fine and runs and drives great. Just can't figure out whats causing it to do this. It is one sudden "clunk, pop, etc" and then its back to running normal. Has happened with the cruise on and off. Seems to happen when its starting to pull down as you approach a hill, but it doesn't down shift..... ???? Does anyone have any idea what this could be? Missing issue? Rear end? Transmission? It's driving me nuts and not sure what it is. Thanks!!

 

 

Not quite enough to go on here Alan. Single clunk or bunch of clunks, like a shudder? Loud clunk? Can it be repeated under those conditions or is it random? Is everything else otherwise run fine, ride fine, sound fine, etc?
- A single clunk could simply be the torque convertor lockup disengaging (normal under increasing load). The RPM change at 65 mph may be as little as 200 rpm and other than a momentary tiny thump feel in the seat of the pants it may be otherwise imperceptible.
There are other possibilities, but we really need a better description; intensity, duration, ...

 

The truck is in near perfect condition for the age and miles on it. Runs great. When I first got it, I did have a few issues getting it started..like it took awhile to get fuel pumped to it. That has gone away after owning it and driving it for a week or so. Now it starts right up all the time. I first thought it just had sat awhile and hadn't ran much. Then, I started noticing this Jerk or clunk when driving under those conditions I described. Being my first Dodge i've owned, I didn't realize at the time that you had to check tranny fluid at idle and in Neutral. So I had been checking it in park and every time I did it registered low. I started adding fluid thinking I had a leak somewhere that wasn't visible. It continued to do this every once and a while like when I thought fluid was getting low. So I added more each time and when I did it ran fine after that.

So thinking it was the transmission, I took to a tranny shop and they could not find any leak at all, so I had them drop the pan and service the transmission with new filters and new fluid. They said every thing looked great with no wearing visible. So thats why I don't think its transmission related really...but I'm not sure. So I got that fluid issue figured out and can now pull a dipstick correctly..haha.

Before going to the tranny shop there was one time where I felt the "jerk or clunk" and my tachometer went to 0 and then came back at normal RPM, all happening around 45 mph while I was gradually accelerating. But that was the only time it was that "serious". It must not have done it while they had it in the shop since they said they drove it like 30 miles to see how it ran.

I apologize if my description is vague....its just really weird to me. Its not really a noise, you feel it, and its very noticeable and kind of concerning. It is a sudden jolt or jerk. One time. Not repetitive. Nothing seems to change on the RPM side of it. I almost thought it was when approaching an incline and the truck is trying to decide to down shift and rev higher RPM or maintain where its at... I'm not sure. After reading online about other dodge stalling problems or misfire bucking and jerking...that's why i'm calling it a jerk now since that may be a better way to explain it. It happened twice to me yesterday, once driving 20 miles into town with cruise off, and once driving back home with cruise set at 62. But today I drove it the same distance and it hasn't done it at all. It seems to be just every so often.

There is no check engine light on...transmission shop said they hooked it up and no codes were being thrown at the time. So today I gave it a Seafoam treatment and went ahead and replaced the Crankshaft Positioning Sensor since it is a cheap part and easy fix. Only reason why is I read online where people have had issues with misfires and stalling... just figured what the heck might as well. Hopefully this gives you guys a little more information...But I haven't really found much online that sounds like an exact similar problem...so we will keep driving it and see what happens. Thanks!

 

Ok awesome, that gives a much better picture with pertinent background.

It is sounding like it is actually dropping off, stalling. From what you have shared it may be from a fuelling or throttle problem of some kind. You mentioned some difficulties when you first got it. The problem could be related.
- If it was a misfire, or sensor timing problem, the PCM should capture a code.
- If it was an EGR valve problem, the PCM also should capture a code.
- If it simply running out of fuel, there is usually no code. ... perhaps there is an intermittent fuel pump or injector issue?
- If it is a dirty sticky throttle body (TB) or throttle position sensor (TPS) in the TB, there may be a dead zone on the sensor where the signal sharply drops off, so the PCM pulls back hard until TB moves a bit where the PCM sees a feedback signal again. PCM may not trip a code if it isn't severe enough. You could do some road tests for this. Find a long straight stretch. Gradually increase throttle from none to floored. Note if there is a position that it sags or stutters. Try it again, see if it does it at the same foot pedal point. Another way is to get a multimeter, unplug the TB/TPS, and check as the throttle is stroked and as the butterfly is moved manually. The road test is much more fun tho. More wind and hear that hemi roar. A manual cleaning of the TB may be helpful.

On the transmission, yup, check level in neutral. There is a known issue with some batch or types of filters that become cracked or do not seal properly. What happens is a sluggish transmission performance, a bit jerky sometimes, slippy others, normal others. When level is checked it looks fine. I had this problem develop on mine about 15k after the transmission service. Replacing with genuine Mopar filters and fresh fluid fixed it. Your issue does not sound like transmission at all. See above suggestions. Surely there will be more insights from other members soon now that there is more info.

Hope that helps!

 

Awesome input, thank you very much! I was down to thinking it was fuel or engine related. I will be hopefully taking it on a 5 hour road trip in a couple weeks so that will be a good test to see how often it happens while its running for awhile. I will take the throttle body off soon and check it out and see what it looks like. I'll be sure to check back and see if anyone else has any input for this.. Like I said, this is my first Dodge i've own, well, the wife has a Dodge Avenger, but first v8! So yes I am really getting used to liking that Hemi!! Excited to learn more from you guys. Thanks.

 

Looking at the mileage in your original post, something else to check while puttering around cleaning up that throttle body. Take out the front spark plug on the driver's side and have a look at it. Check a couple more. The hemi takes standard plugs and these do burn out in 30-50k. They do need replacement 4 to 5 times over the lifetime of the truck. If the plugs look original or well worn, then absolutely put a spark plug change on your todo list. Plugs can also cause your problem. Do not put platinum or iridium plugs in. Use only standard copper plugs. The stock plug spec will be on the emissions sticker on the underside of the hood, just look up at it while you are checking the TB. The oem plugs on the sticker are usually the Champion 570 (RE14MCC4 Copper Plus). I use the equivalent NGK #5306 (LZTR4A-11 V-Power). I prefer the NGK. They have performed flawlessly and are a much better quality and better overall than the Champions imho. If you find platinum or iridium plugs in there when you check, take them out! The hemi takes 16x spark plugs. It is good that it doesn't like fancy precious metal ones. At 16x it is good that regular plugs are economical and the hemi runs best on them. ... one more idea for your consideration. I am actually just about to do the plugs on mine, third set, as the new NGK plugs have just arrived in the mail on Monday.