97’ Ram 1500 4x4 ST 5.2L 5 spd. manual trans (nv3500) truck is bone stock 80,000 orig. miles

Truck did not have this noise when I bought it 4 or 5 years ago.

About a year ago the clutch wore out so I replaced it with a sbc stage 1 daily driver. Not being used to the new clutch grabbing right off the floor the truck jerked, lurched and jumped. Now I have this knock every time I let off the clutch pedal in neutral at idle. It’s just a single knock sound almost like if you took a hammer and lightly hit the side of the bell housing.

However, if you put it in 1st at idle and press the clutch pedal halfway and hold it I get a constant knock like if you were to keep tapping the bell housing with a hammer. Pedal completely down no noise. Only when releasing the pedal and just before you take your foot off does it make the knock, unless of course you hold it halfway.

Shifting and driving seem normal, clutch seems to grab fine when cold. Only thing I’ve noticed is that when I drive it for a long period maybe 40min to an hour it seems like the clutch slips for maybe a few seconds as I let off the clutch as it doesn’t seem to gain speed as I accelerate. Also I’ve noticed that I get that same sound if I’m in reverse and push the clutch pedal down.

I had our mechanic at work look at it today and he thinks it’s the throwout bearing. My thoughts were possibly shift fork, pressure plate, crush sleeve, or the snap ring in the transfer case where the yolk and transfer case output shaft meet.

Motor mounts and trans mount were changed last year, u-joints were changed about 3 or 4 years ago.

I’m stumped, if I have to buy another clutch then it is what it is, no big deal. I just don’t know what the hell this noise is. Thanks for any help and advice. Also sorry for the long post. I just wanted to make sure I covered everything.

 

Dual Disk clutch? I am not sure about their behavior when they engage, never driven one, but, the knock is NOT normal. and it does sound like *probably* the throwout bearing.....

 

No sorry I didn’t specify, it’s the stage one daily driver.

 

Ah. The "DD" got me.

Still, sounds like TO bearing to me....

 

Ha sorry bout that. Ok, I didn’t know the TO bearing made that kind of noise. When I changed the clutch before the TO bearing was bad as it made the famous squeal when letting the clutch out in gear.

 

Depending on the failure mode, they can make all sorts of interesting noises. Unfortunately, it is NOT easy to verify.

 

**UPDATE** So I had some time and changed out the throwout bearing, clutch fork and pivot ball. Made sure flywheel and pressure plate were torqued to spec and inspected for damage, everything checked out ok. Re-greased pilot bearing, input shaft, pivot ball, clutch fork and inside bore of throwout bearing.

Put her all back together and it definitely shifts better but the previous symptom/issue still remains. Drove for about 20-30 min today and noticed it seems real prominent when shifting from 4th to 5th at about 40-45 mph accelerating to pass a car.

It also seemed jumpy/bouncy, and when I would let off the gas pedal it would feel almost like a bad motor mount or trans mount as I would hear and feel a thud. I could also every so often feel the previously mentioned clunk or clack sound in the shifter. It definitely sounds like metal hitting metal somewhere. I also noticed it will make that sound with the clutch pedal pressed down and when I put the shifter into first gear.

The noise is definitely coming from the front somewhere between the trans and motor, I just can’t seem to pin point it.

Thought I’d update you guys and see what your thoughts are as there’s obviously some other kind of underlying issue somewhere. Appreciate your help.

Also this clack sound seems to be worse when driving for a while after everything is hot.

 

Didn't the NV trannies have some issues with the fifth gear nut coming loose???

 

Im not sure about that, or at least I haven’t found anything regarding that, but I’ll definitely do some research on it.

This past fall though I did split the case and install all new bearings and seals hoping that would fix it, but it did not. The only things inside that I did not replace were the syncros since they were absolutely fine, moved fine and showed zero signs of wear. So with that said I did not separate any of the gears from the shaft nor did I notice anything loose or out of the ordinary.

I’ve been chasing this issue/sound for about 3 years now. I’ve never had something this difficult to diagnose so it’s a first for me.

I know our mechanic at work wanted to see if the crankshaft was moving abnormally when that sound would happen and he said it wasn’t so I don’t think that’s the issue.

 

According to my research the fifth gear nut seems to be an issue on the NV4500 and not the NV3500. Here is an exploded view of the NV3500 main shaft. I don’t see anything labeled on there as it having a nut for fifth gear. I also don’t have the rattle that’s associated with that.



Upon doing more research this morning, I think I’m leaning towards the pressure plate. Reason being is I have at least 2 of the symptoms of a bad pressure plate which are over heating (accelerating speed doesn’t match engine speed/rpm when hot), and clutch release noise. Thoughts?