ongoing stange noise with my GQ

hi all,

I've had a mystery noise coming from my GQ on and off since a couple of months after I bought it. It really is quite strange, there's a bit of a story to it and I'm not 100% sure if it's been the same noise all along or something different each time!

After a month or so, I got a whining noise from around the engine area and I noticed the power steering fluid was low, there was a small leak from one of the lines, so I fixed it, topped it up and all was ok for about 1 week. Then the same, or a very similar noise came back, so I thought it was the ps pump which was knackered. It was pretty much a continuous whining noise. However the noise did not appear to be coming from near the pump, so I took the pump belt off and the whining noise was still there. It varied with engine revs and appeared to be coming from the auto trans. I noticed the fluid was over full so I dropped the level down and the noise almost went away. I then change the trans fuild with Nissan d-matic and the noise went completely. However about 2 months later the/a noise came back. Initially I thought is was the same noise, but this time it's more of a gear noise, like the noise of an RC car plastic gearbox, but louder, like a buzzy-zingy noise (if you can imagine!). Now, it's there for a few seconds when the engine is started first thing in the morning then goes away. It comes back after about 30mins of driving when everything is hot. It's most noticeable between 1800-3000rpm and occurs in any gear or neutral/park. I still think it's the auto trans because when I increase the oil level it gets worse. If I drop the trans oil level, it gets better, in fact it nearly goes away when the level is dropped below the minimum on the dip stick! Even more strange, it gets worse on left hand bends!! Yep, even the slightest left bend or when the car is tilted to the right (same g-force effect) it's there continuously. But on right bends, or tilted to the left, it goes away.
The fact that a lower fluid level makes less noise, taking a left bend (hence shifting the oil level to the right) makes it worse and cold start up makes it worse (as the oil level in the sump of the gear box will be higher until it's distributed around the box), is making me think that it's something in the gearbox on the right hand side, getting noisy when cover in oil....unusual to say the least.

Any ideas at all what this crazy problem could be?

Thanks

The best advice I can give you is take it to a transmission specialist and let them have a listen to it.

Tony

yeah, I was thinking that might be the only thing to do. Wanted to check here first though as I really don't trust garages, they're just a license to print money. I bet they won't be able to tell me anything without stripping it down, costing $$$$ and probably only actually done if I watch them and then they won't be able to do it there and then, it'll take hours or days, and then something costing many more $$$$ will need replacing without a shread of evidence. Sorry I just hate garages. Like when I got my tyres fitted, I paid extra for wheel alignment, yet I checked the threads on the tie rod after and they were still covered in mud, so hadn't been adjusted. So I specifically asked about it when I collected it and was told it had been adjusted.....couldn't be bothered arguing about it as wife and kids were waiting etc. etc.

Moan over!

Must be some theories out there what this noise could be. Is the oil pump on the right of the transmission?

If you take it to a mechanic they will probably just tell you the gearbox is stuffed and take the transmission out so a transmission specialist can rebuild it. Cut out the middle man and take it to the trans specialist yourself.

Tony

Thanks Tony, I'm looking for a specialist in my area, problem is they only open for a few hours Saturday morning and I need the car for work during the week, does make it difficult.

Thinking about the problem, I'm wondering if the noise is aeration of the oil. I've heard this can happen if the oil is over filled, but according to the dipstick and checking it after a run with it in park, the level is ok. I dropped the oil level to just below minimum and there was no noise during my hour's drive to work this morning and the gearbox operated fine. Also, when I drained the oil from the gearbox yesterday, I did it with the engine running and with the car tilted to the right on some ramps, so the noise was there. The oil coming out was very bubbly. Also, I've noticed that normally after this noise has started, the gear shifts become a bit strange and more sluggish and it doesn't lock up the torque converter well, ie it slips. I initially thought this was an electrical problem, as when I switch off the engine for a while, then restart, it works ok. Now I'm thinking if it's aeration of the oil, the valves and solenoids won't work effectively thus causing these symptoms. After stopping the engine for a while, all the bubbles go and it then works ok. Seems to stack up. Could this noise be aeration of the oil? Could my dipstick actually be wrong?

unusual has got me i have no idea its not timing chain ??? or oil pump maybe ??? dunno sorry cant help

Quote:

---

Originally Posted by boggy2006

Thanks Tony, I'm looking for a specialist in my area, problem is they only open for a few hours Saturday morning and I need the car for work during the week, does make it difficult.

Thinking about the problem, I'm wondering if the noise is aeration of the oil. I've heard this can happen if the oil is over filled, but according to the dipstick and checking it after a run with it in park, the level is ok. I dropped the oil level to just below minimum and there was no noise during my hour's drive to work this morning and the gearbox operated fine. Also, when I drained the oil from the gearbox yesterday, I did it with the engine running and with the car tilted to the right on some ramps, so the noise was there. The oil coming out was very bubbly. Also, I've noticed that normally after this noise has started, the gear shifts become a bit strange and more sluggish and it doesn't lock up the torque converter well, ie it slips. I initially thought this was an electrical problem, as when I switch off the engine for a while, then restart, it works ok. Now I'm thinking if it's aeration of the oil, the valves and solenoids won't work effectively thus causing these symptoms. After stopping the engine for a while, all the bubbles go and it then works ok. Seems to stack up. Could this noise be aeration of the oil? Could my dipstick actually be wrong?

---

Your main concern will be finding out what is causing the oil to become aerated.

Tony