What is causing this noise??

[MadCharger]

Since swapping the SRT differential and '09 axles in my RT, I've been having a rough feeling on the highway. It's sort of like running over a light rumble strip every 20 feet - although not quite that harsh. If I have the radio off, and just cruising at 70, it's very consistent, even though some may not even notice. I can actually feel it in the pedal slightly also. I know it has to do with either the driveshaft or the differential, but don't know which to change. In honesty, I'd like to just change both, since the diff sings quite a bit, and the couplers on the driveshaft were quite worn. Learned my lesson buying junkyard parts when I could've gotten new parts from AllUSA for the same price. Anyone have any opinions on what I should be checking?

[Hemi31]

couplers and center support bearing first,then look at the pinion bearing,also I will assume you got the driveshaft in phase using the keyway and didn't force it together.

[Charger4Life]

Could it have anything to do with putting a SRT rear driveshaft with the R/T front? Mine sorta does this as well, and sings sometimes.

[Hemi31]

Could it have anything to do with putting a SRT rear driveshaft with the R/T front? Mine sorta does this as well, and sings sometimes.

It won't if it's in phase.If you used the keyway it should be in phase.The top of the 4 flange yoke should be dead center of the V of the 3 flange yoke.

[Charger4Life]

You are talking about the spline keyway where the driveshaft only goes one way? I found that out the hard way.

[PaCharger]

If it happens every 20 ft? Did you check the bolt length on the yoke - that it clears the diff carrier? If you used the 5.7 bolts on the 6.1 diff you'll note that 4 of them are just a CH long. I knew about it, but honestly only 1 of them every so slightly nicked the bottom of the carrier and then again at the top.

[JonzMgnm]

If it happens every 20 ft? Did you check the bolt length on the yoke - that it clears the diff carrier? If you used the 5.7 bolts on the 6.1 diff you'll note that 4 of them are just a CH long. I knew about it, but honestly only 1 of them every so slightly nicked the bottom of the carrier and then again at the top.

What's a CH long?

[Hemi31]

What's a CH long?

It's a technical term

[Charger4Life]

If it happens every 20 ft? Did you check the bolt length on the yoke - that it clears the diff carrier? If you used the 5.7 bolts on the 6.1 diff you'll note that 4 of them are just a CH long. I knew about it, but honestly only 1 of them every so slightly nicked the bottom of the carrier and then again at the top.

Yeah Madcharger and I found that out the hard way as well.

[MadCharger]

couplers and center support bearing first,then look at the pinion bearing,also I will assume you got the driveshaft in phase using the keyway and didn't force it together.

I didn't know about the keyway on the front driveshaft until Jason mentioned it when doing his. Mine slid right in when I was putting it together, so I'm assuming I lucked out and had it lined up already when I assembled it. I do feel it must be the driveshaft, so I'll try popping it off and taking a closer look.

If it happens every 20 ft? Did you check the bolt length on the yoke - that it clears the diff carrier? If you used the 5.7 bolts on the 6.1 diff you'll note that 4 of them are just a CH long. I knew about it, but honestly only 1 of them every so slightly nicked the bottom of the carrier and then again at the top.

Yep - we found that out the hard way too. We hack sawed them off while they were on the car. I think I'm still sore from that!

What's a CH long?

You won't find this term in the manual. It's more of a term that comes up in the garage while on your back trying to hack saw the muther off! Generally only used while the children are not around....