Weird Noise Comming from transmission?

[wiseguy55]

Hey guys, I have a 2k2 QX4 and recently had a code P0740 come up last month. Read the code and replaced the torque converter solenoid valve in the transmission. Since I had the oil pan down I did service the transmission with new oil filter and new transmission oil. I put everything back together and filled it up and the MIL went off! Cool, I fixed that problem and it has not come back in about one month now.

Now here is my current question. I just noticed that my transmission is doing this funny noise (i think its the transmission, not 100% sure) when shifting from 1st to 2nd. The noise is hard to describe but I'll try my best to describe it. First of all it is very fine and not super loud, it sounds like some sort of wire is touching some grears as they spin. Again it only happens when shifting from 1st to 2nd and does not happen all the time. There is no pattern, it is intermittent and random. It drives smooth as pie and have not noticed anything with the performance. It has been doing this for about one week now and I though it would just go away. The only way I can hear it is if I lower my windows and drive past parked cars and I can get the noise to happen sometimes, it does do it everyday, but like I said not all the time, and it only does it when shifting from 1st to 2nd.

I hope you can help and point me in the right direction.

[ARKQX33V6]

It is very difficult deciphering noise(s) over the Net. But ...
Check your fluid level, be sure you are not over filled, check when cold and when hot.

Does the whine, whirr, tick happen when transmission is ho or cold, in 2 WD or 4 WD, is your transfer case planted in the correct position or maybe the transfer motor is running.

Go under the car and check for hydraulic leaks, mechanical interferences. Check your tires, drive shaft(s) and brakes

Try to isolate the noise.

[wiseguy55]

Fluid level is perfect. I have a 2wd so no transfer case. It does seem to happen when the transmission is hot and not when cold.

I'll take your advice and check for any leaks, mechanical interferences, drive shaft and brakes. Thanks for the suggestions.

[choodles]

Hey WiseGuy 55

Looks like we having the same issue at about the same time........Check Engine light recently came on, diagnosis it with OB II yesterday and got the same code (P0740-Torque Converter) on my wife's 2001 QX4, I was thinking about taking it in the transmission shop, how much can I expect to pay to replace Torque converter?

Do you now what the pros and cons are about driving with code p0740?

many thanks

[wiseguy55]

Make sure it is the torque converter and not just the solenoid. Lets hope it just your solenoid like it was on mine.

From what I read on the internet and reading my workshop manual, the "P0740 Torque Converter Clutch Solenoid Valve Circuit Open" code prevents lockup of the 4th gear when driving on the highway at speeds of over 55mph. I changed it out myself and was very easy to do. The testing of the solenoid is very simple too if you follow the procedures in the workshop manual. Once I tested mine it was bad and then I ordered it and replaced it. You can find it fairly cheap on ebay for around $80 shipped (l paid $160 for mine at the dealer).

[iceman14n]

DUDE!!!! how many KM or miles did you get the transmission oil replaced? and did you ever have it replaced before... tell me exactly!!!

[Towncivilian]

With a pan drop you only replaced about half the fluid. Try another drain & fill (in my experience it's about 4 quarts with a stock 2WD setup). What ATF did you use? How does the fluid level & condition look if you pull the dipstick after the proper checking procedure? The checking procedure is: stop on leveled ground with the parking brake applied after driving around for about 15 minutes, shift the selector lever through all the gears slowly and back up to P, then pull trans dipstick to check fluid level. Examine for metal particles or other contaminants, and verify that it's pink/red when blotted on a paper towel and does not smell burnt.

[wiseguy55]

135K miles. I dont know if the previous owner had ever changed it. There was no metal shavings or foreing material in the pan or magnet. Just the norman very finely particles of normal wear and tear.

DUDE!!!! how many KM or miles did you get the transmission oil replaced? and did you ever have it replaced before... tell me exactly!!!

I was exactly going to do this sometime this weekend. I only got about 4 quarts out with the transmission service I did. The manual did infact say to do it again if the oil seemed to be dirty still. My oil is not dirty but I will do it for peace of mind anyways. I checked it following this exact method. Weird little noise is still there and bugs the crap out of me! Again, not a single hint of the performance of my truck detiriorating. The noise is very fine, imagine a paperclip touching the teeths of some gears as they spin, and it only does it for about 1 second when shifting from 1st to 2nd and it only seems to do it when hot. Weird.

With a pan drop you only replaced about half the fluid. Try another drain & fill (in my experience it's about 4 quarts with a stock 2WD setup). What ATF did you use? How does the fluid level & condition look if you pull the dipstick after the proper checking procedure? The checking procedure is: stop on leveled ground with the parking brake applied after driving around for about 15 minutes, shift the selector lever through all the gears slowly and back up to P, then pull trans dipstick to check fluid level. Examine for metal particles or other contaminants, and verify that it's pink/red when blotted on a paper towel and does not smell burnt.

[ARKQX33V6]

Wiseguy, since you have changed oil and it seems OK, how is the level. These dip sticks are useless if any oil is poured down them when filling back the transmission. If dumping oil measure that quantity then replace that exact amount, wait for the car to sit 24 hrs so any residual oil along the dip channel is gone, then do the correct check at either cold or hot.

Oil must not be low or high, because the transmission is a hydraulic actuated mechanical device.

As an hydraulic device it has electro mechanical operated valves, solenoids. These solenoids have a primary electric actuator ( coil, magnet) that pushes/pulls an hydraulic actuator that controls pressurized oil. This pressurized oil travels to, and through the valve to its intended actuator. BUT...

The control devices that are hydraulically made to operate must be kept clean. These devices can bung up with nicks and rough spots or even the small particles that get floating around in the soup of ATF.

These solenoids can also get hung up or delayed in action by having dirt crud sticking to their magnetic core surfaces and then the action of the solenoid gets lengthened, delayed or a non event.

The simple action of dumping the ATF every 2 years becomes an insurance policy by removing all or some of the crap and can even remove the build up on the valves by the action of fluid escaping out the drain hole. Examining this drained fluid will show what comes out.

The torque converter another enclosure does not get as contaminated and it can be a lengthy job to replace it.

[wiseguy55]

ARK,

Thanks for the tips. I'll triple check my fluid level and condition again. The noise is still there as of today. And now I just noticed that it even makes it in shifting from 3rd to 4th. I'm even starting to think that the noise might be something electrical. I'll check the fluid again for proper level and condition. Heck I might even change it again this weekend for peace of mind since I only got out about 4 quarts when I did the transmission service.

[ARKQX33V6]

If it is electric noise, take a walk around with hood up, pay attention to all sounds, any of them the noise you seek? The canister valve under the hood controlling the evap canister in the rear can get very noisy right at start up but the engine noise disguises it.