My xterra has been doing this pretty bad lately and seems progressively to be getting worse. When coasting downhill 40-60ish mph and tapping on the throttle (OD enabled), with the clunk I am also getting a drivedrain "bounce/echo" sensation.
I use to only feel this around the 40-45 mark when OD engages but i'm beginning to be able to reproduce it closer to 65 now. My rear diff fluid looks real good, my U-joins seem all right as I cannot find any play in them turning the driveshaft back and forth manually with my hands.
My transmission it self may be due for a fluid change/flush though, it shifts fantastic in all gears under light and heavy throttle with zero issues, going in and out of overdrive is smooth for the most part, its just when I release and apply small throttle while driving in overdrive that I get this clunking sensation, could slightly worn tranny fluid make the TC lockup act skittish?
Here's something I noticed just this morning, about 70F outside, I started up my xterra and immediately got on the highway, only about 3 minutes into driving and at 45-55mph I was not able to reproduce the clunk what so ever. It felt like it should, drivetrain felt tight with no slop. I know for sure at that moment it was engaging into awd because I was pushing the O/D button on and off and the RPM was raising/lowing. As I kept driving, around 5-7 minutes in I could tell it was beginning to loosen up, letting off and reapplying throttle began to produce the clunk again and progressively got worse as it continued to warm up.
What do you guys think this could be? Something is expanding from heat friction or something of the sort to begin to allow this to happen, maybe the U-joints? I don't think I have ever checked the U-joints for slop after a pretty distant drive.
Just really wanting to get to the bottom of it, though I'm trying to accept it as normal, it just doesn't seem right at all.
As best as I can figure so far, its drive train slack in the auto drive line. At least that is what it seams like to me. If I keep the throttle under 2% (as measured by the BD) I don't seem to get a clunk when getting back on the gas. And I only get it when the TC is locked..
Tried Turning OD off, don't think it helped... I'm gonna bring the truck to the dealership this weekend so it's on record that there was a drive train issue from the beginning when the truck was bone stock.
If this is normal for the truck that's fine i can learn to live with it, but if it does get worse, I plan on lifting the truck 2" next week with spacers and shackles, and I don't want the dealership to be able to try tell me the problem is directly caused by my lift because the problem wasn't there before i lifted it.
Took my truck back to the dealer yesterday to get my replacement radio installed, and i also told them to check out this clunk.
I waited there for two hours and they called me up, said the truck was done, they replaced the radio & fixed my bum speaker, and they couldn't replicate the clunk I asked them to check out.
I was keeping an eye out on the parking lot cause you can see the entrance and exit to the dealership from the waiting area and my truck never left the property so they didn't even bother listening for it... So I didn't bother to call them out, i just politely asked to take a tech for a ride. My service rep said no problem, and said he would go for the ride with me, when he went to grab my keys the other service rep who checked me in tried to reitterate that it's a normal sound from play in the drivetrain because the drive train is so complex and has so many U joints and drive shafts. So I told him I refuse to accept that a brand new $30k truck would have that much slop in the drive train when none of my subarus made any noise like that, the 12 year old ford ranger at work doesn't clunk like that, and my buddys 02' F250 with 200k miles doesn't clunk like that, and all their drivetrains are just as complex if not more so then my frontiers, so he quited down after that and my rep and i left for a ride.
During the ride i was having a tough time replicating the clunk, but eventually it started to do it a little bit and the rep acknowlaged it, and I pulled over to turn around. OT here: when i pulled over i checked my bum speaker, and sure enough it still wasn't sounding right and the rep acknowlaged that also but said since they already replaced the speaker and radio he didn't know what it could be, I said it's probably the amp, he said he thought the amp was in the radio, then I laid some knowledge from the service manual on him and he said they would replace the amp...
Anyway back on topic, so i turned around started heading back to the dealership and without even trying the truck clunked really hard and the rep said oh yea i definitely felt that one. When we got back to the shop my rep explained that they were out of Loaners that day and that I could drop the truck off next week and they would give me a loaner while they further diagnose the clunk and replace my amp. Hopefully they'll come up with a solution.
Just to play devils advocate: My dealer never takes a car out the front of the lot. There are two exits in the back, trough the maze of new cars, that they always use. I only know this because I am friends with some people at the dealer. And every car dealer I have ever dealt with had at least one back exit. Sometimes it is chained or gated, but it is still there.
But at least they acknowledged that you have a problem this tome, and agreed to take the truck in for a serious look.
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