Help : 7at transmission leak !!

ZeN · 03-30-2014, 03:05 AM

Gents,

Last Thursday i went to local Nissan dealer to have my Engine oil and Transmission oil change. That same evening i saw white smoke coming out from the back of the car while coming home, my first thought was the flex pipe are done since it scrape so much so i sent the car to an exhaust shop to have a custom test pipe + y pipe + 2 x 12'' resonator straight through. The car finally howl like a GTR but too much on the loud side. While coming home after having a good run i saw the same white smoke again, WTF !!. Next morning on Saturday i sent it back to the exhaust shop, once i put it on the lift to check for leak - none but i saw a big splash of transmission oil residue on the Driver side (RHD). I quickly check both the drain plug and overfill plug and it was not leaking, when i trace the splash only the right driver side (RHD) that being splash all the way up to the wire connector that connect to the housing + the 2 cooler line area. Passenger left side is clean spotless. I wipe everything clean, called up my dealer and told them something on the transmission is leaking and set for an appointment this morning. On the way back it started to smoke when i reach my house after a good run, i also feel hesitation on acceleration on 3rd gear and it does not respond to my throttle. Downshift and Upshift has no lag and seems normal. No codes being throw out, i was expecting SES light to come out after the test pipe installation.

This morning i sent it to the dealer, junior tech works on Sunday. He have a look on the transmission and he says yes it leaks and says that it is from filling too much but he couldnt identify where the leaks come from. He told me to give it some time and it will stop eventually after the fluid drop to where it should be. I said f*** this junior tech, i ask him to call the senior mechanic for tomorrow appointment and drove my car home. On the way home i still see the smoke but after quite some time, believe it is heat related.

Question before i get to the dealer tomorrow :

1. Will the ECU put a safe mode if it sense the transmission get too hot ?
2. Is there any area where the transmission oil could come out if its been overfill after both the drain hole and overfill hole plugged properly. I saw right below the 2 cooler lines there's a screw and it looks like a hole pointing up next to the screw but i don't know what it is.
3. Will it be better if i just open up that overflow plug, let it drain from there, put it back together and drive normally ? Assuming temp is around 40 deg C that should put the fluid at correct level, right ?
4. Does any of you 7AT owner who had a test pipe have this issue ?
5. What will be the best way to identify where the leak come from cause it only leaks when the transmission is hot after a run.

Car is out of warranty...zzzzz, 60k miles, 4 yrs.

Zen

megalapagas · 03-30-2014, 03:24 AM

I'm in for Info since I too will be taling in my Z for a Tranny oil change I'm at 74,xxx miles and No OP the test pipes shouldn't be a problem I have Non resonated TP from F.I and everything is fine.

ZeN · 03-30-2014, 07:32 AM

Thanks mega for confirming that, i just learned there's also a breather tube right on the top of the case/housing, maybe that's the one squirting the oil out but the question will be why at high temp and not low temp. Will know more tomorrow.

Fountainhead · 04-01-2014, 10:14 PM

Hey Zen,
Did you find anything out?

ZeN · 04-02-2014, 05:30 AM

Yeah, the senior tech confirmed that he overfilled it. The fluid came out from the breather on the top. He drained about 1.5 litres of fluid and recheck the level and its all good.

Now we know that the fluid wont leak unless its getting hot when overfill.

03-30-2014, 03:05 AM	#1 (permalink)
ZeN Base Member Join Date: Apr 2011 Location: Malaysia Posts: 116 Drives: 09 PW 7AT 370z Rep Power: 14	Help : 7at transmission leak !! Gents, Last Thursday i went to local Nissan dealer to have my Engine oil and Transmission oil change. That same evening i saw white smoke coming out from the back of the car while coming home, my first thought was the flex pipe are done since it scrape so much so i sent the car to an exhaust shop to have a custom test pipe + y pipe + 2 x 12'' resonator straight through. The car finally howl like a GTR but too much on the loud side. While coming home after having a good run i saw the same white smoke again, WTF !!. Next morning on Saturday i sent it back to the exhaust shop, once i put it on the lift to check for leak - none but i saw a big splash of transmission oil residue on the Driver side (RHD). I quickly check both the drain plug and overfill plug and it was not leaking, when i trace the splash only the right driver side (RHD) that being splash all the way up to the wire connector that connect to the housing + the 2 cooler line area. Passenger left side is clean spotless. I wipe everything clean, called up my dealer and told them something on the transmission is leaking and set for an appointment this morning. On the way back it started to smoke when i reach my house after a good run, i also feel hesitation on acceleration on 3rd gear and it does not respond to my throttle. Downshift and Upshift has no lag and seems normal. No codes being throw out, i was expecting SES light to come out after the test pipe installation. This morning i sent it to the dealer, junior tech works on Sunday. He have a look on the transmission and he says yes it leaks and says that it is from filling too much but he couldnt identify where the leaks come from. He told me to give it some time and it will stop eventually after the fluid drop to where it should be. I said f*** this junior tech, i ask him to call the senior mechanic for tomorrow appointment and drove my car home. On the way home i still see the smoke but after quite some time, believe it is heat related. Question before i get to the dealer tomorrow : 1. Will the ECU put a safe mode if it sense the transmission get too hot ? 2. Is there any area where the transmission oil could come out if its been overfill after both the drain hole and overfill hole plugged properly. I saw right below the 2 cooler lines there's a screw and it looks like a hole pointing up next to the screw but i don't know what it is. 3. Will it be better if i just open up that overflow plug, let it drain from there, put it back together and drive normally ? Assuming temp is around 40 deg C that should put the fluid at correct level, right ? 4. Does any of you 7AT owner who had a test pipe have this issue ? 5. What will be the best way to identify where the leak come from cause it only leaks when the transmission is hot after a run. Car is out of warranty...zzzzz, 60k miles, 4 yrs. Zen Last edited by ZeN; 03-30-2014 at 03:08 AM.

03-30-2014, 03:24 AM	#2 (permalink)
megalapagas Enthusiast Member Join Date: May 2013 Location: McAllen,TX Posts: 457 Drives: '10 370Z Tour A/T Rep Power: 12	I'm in for Info since I too will be taling in my Z for a Tranny oil change I'm at 74,xxx miles and No OP the test pipes shouldn't be a problem I have Non resonated TP from F.I and everything is fine. __________________ GTM 34 Row Oil Cooler \| K&N Drop Ins w/ Z1's Post MAF Tubes \| F.I Non-Res'd 2.5" T.P w/ CF CBE \| Axis Wheels \| Piecing together My Own Custom T4 Top Mount Single Turbo Kit Still in the works \|

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03-30-2014, 07:32 AM	#3 (permalink)
ZeN Base Member Join Date: Apr 2011 Location: Malaysia Posts: 116 Drives: 09 PW 7AT 370z Rep Power: 14	Thanks mega for confirming that, i just learned there's also a breather tube right on the top of the case/housing, maybe that's the one squirting the oil out but the question will be why at high temp and not low temp. Will know more tomorrow.

04-01-2014, 10:14 PM	#4 (permalink)
Fountainhead Track Member Join Date: Feb 2013 Location: FL Posts: 834 Drives: 2019 Civic Type R Rep Power: 14	Hey Zen, Did you find anything out?

04-02-2014, 05:30 AM	#5 (permalink)
ZeN Base Member Join Date: Apr 2011 Location: Malaysia Posts: 116 Drives: 09 PW 7AT 370z Rep Power: 14	Yeah, the senior tech confirmed that he overfilled it. The fluid came out from the breather on the top. He drained about 1.5 litres of fluid and recheck the level and its all good. Now we know that the fluid wont leak unless its getting hot when overfill.