A
acameltoe
Guest
Hi,
New here so I am sorry for such a long first posting, but this problem is driving me nuts and I have posted on other board with good responses, but nothing that turned out to be the correct problem yet. Hopefully someone here can lend some insight.
I have a 2000 D2 with 128k on it, and over the past few weeks I started noticing a tapping or rapping sound, but only at highway speeds.
It first started at about 70 MPH/2500 RPM and sounded more like a piece of the wheel-well rubbing on a tire and clicking, or possibly something contacting the fan, not a really "metallic" sound it didn't seem.
The sound seems to go away immediately when I let off the gas, but comes back as soon as gas is applied again, so it seemed to be only under load at speed, so I thought perhaps something was rubbing or hitting the fan, but couldn't find anything.
When stationary the noise does not happen and engine sounds fine from idle right up to high RPMs.
Oil is fine. Reads a bit high on dip stick, but has since mile 1 that I have owned it and I always drain well, and fill with amounts spec'd in book. That has never been a problem for 128k now. Just a wierd stick I guess. Diff's and T-Case are all full as well.
Took out plugs and replaced with new champions. Still the same.
Front driveshaft out...same noise. Viscous fan out...same noise
Had a shop look at it and they thought it might be the flex plate, but scoped it and couldn't tell from that. Said most likely $800 + just to get in and check it. Ouch.
Followed up on the cat idea from another board and driver's side cat had a bit of a rattle, so I replaced them in the hope it was one of the bisquits in the cat rattling around and then flipping back into place when speed/pressure changed, but that didnt help. At least I have new high flow cats.
Any ideas? I would hate to pay someone to pull the transmission off to check the flex plate and have that not be it. It doesn't make sense to me that it would only do it after a certain speed or under a really heavy load, say up a steep hill, at decent speed only. Once it starts now it will do it at pretty low speeds as I slow down but keep load on it, but once I stop I cant hear it anymore to check. But with flex plate, isnt it constantly spinning? Would speed really effect it so much it would go from perfectly normal to a pretty loud banging/tapping sound? Also, no oss of drive from transmission, just lack of power when it gets really loud and starts missfires.
Deffinetly changes with RPMs. At say 1500-200 after it has started it is a low pitched sound but deffinetly not 1500-2000 times a second. More like only a few. Kind of like a manifold to Y pipe leak sound, but rev it and frequency increases as does pitch of sound. More a rapping sound then, and louder. but again. I could drive 40-50 miles of side roads and it drives fine. Only have I noticed it on highway or going up a very long, steep grade at over 40 MPH. That is more recent. At first it was only on highway.
I did look inside front inspection hole and found the allen screw I have seem mentioned in other posts. It was indeed showing that it had been rubbing something at sometime, but after removal they problem still exists, same as with it in there, so that wasn't it.
Still getting some missfire codes and the p0171, P0174 fuel trim codes after it really does it bad, and do now notice a lack of power when it is happening and then service engine light blinks till I let it coast a bit and then back to normal. Also getting some p03xx missfires here and there and an intermitant "Gear 3 incorrect ratio" code.
Really driving me nuts now after swapping out cats with that not being the cause, and looking at possibility of pulling transmission off to the same end.
Anyone else have an idea I might try to look into?
Thanks any help. Tough one to diagnose.
John
New here so I am sorry for such a long first posting, but this problem is driving me nuts and I have posted on other board with good responses, but nothing that turned out to be the correct problem yet. Hopefully someone here can lend some insight.
I have a 2000 D2 with 128k on it, and over the past few weeks I started noticing a tapping or rapping sound, but only at highway speeds.
It first started at about 70 MPH/2500 RPM and sounded more like a piece of the wheel-well rubbing on a tire and clicking, or possibly something contacting the fan, not a really "metallic" sound it didn't seem.
The sound seems to go away immediately when I let off the gas, but comes back as soon as gas is applied again, so it seemed to be only under load at speed, so I thought perhaps something was rubbing or hitting the fan, but couldn't find anything.
When stationary the noise does not happen and engine sounds fine from idle right up to high RPMs.
Oil is fine. Reads a bit high on dip stick, but has since mile 1 that I have owned it and I always drain well, and fill with amounts spec'd in book. That has never been a problem for 128k now. Just a wierd stick I guess. Diff's and T-Case are all full as well.
Took out plugs and replaced with new champions. Still the same.
Front driveshaft out...same noise. Viscous fan out...same noise
Had a shop look at it and they thought it might be the flex plate, but scoped it and couldn't tell from that. Said most likely $800 + just to get in and check it. Ouch.
Followed up on the cat idea from another board and driver's side cat had a bit of a rattle, so I replaced them in the hope it was one of the bisquits in the cat rattling around and then flipping back into place when speed/pressure changed, but that didnt help. At least I have new high flow cats.
Any ideas? I would hate to pay someone to pull the transmission off to check the flex plate and have that not be it. It doesn't make sense to me that it would only do it after a certain speed or under a really heavy load, say up a steep hill, at decent speed only. Once it starts now it will do it at pretty low speeds as I slow down but keep load on it, but once I stop I cant hear it anymore to check. But with flex plate, isnt it constantly spinning? Would speed really effect it so much it would go from perfectly normal to a pretty loud banging/tapping sound? Also, no oss of drive from transmission, just lack of power when it gets really loud and starts missfires.
Deffinetly changes with RPMs. At say 1500-200 after it has started it is a low pitched sound but deffinetly not 1500-2000 times a second. More like only a few. Kind of like a manifold to Y pipe leak sound, but rev it and frequency increases as does pitch of sound. More a rapping sound then, and louder. but again. I could drive 40-50 miles of side roads and it drives fine. Only have I noticed it on highway or going up a very long, steep grade at over 40 MPH. That is more recent. At first it was only on highway.
I did look inside front inspection hole and found the allen screw I have seem mentioned in other posts. It was indeed showing that it had been rubbing something at sometime, but after removal they problem still exists, same as with it in there, so that wasn't it.
Still getting some missfire codes and the p0171, P0174 fuel trim codes after it really does it bad, and do now notice a lack of power when it is happening and then service engine light blinks till I let it coast a bit and then back to normal. Also getting some p03xx missfires here and there and an intermitant "Gear 3 incorrect ratio" code.
Really driving me nuts now after swapping out cats with that not being the cause, and looking at possibility of pulling transmission off to the same end.
Anyone else have an idea I might try to look into?
Thanks any help. Tough one to diagnose.
John
