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sprinkles08, ASE Certified Technician
Category: Car
Satisfied Customers: 22675
Experience:  ASE Master and Advanced level certified. Factory trained with 15 years dealership experience
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Nissan x-trail: I have a Nissan X-Trail automatic transmission

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I have a Nissan X-Trail automatic transmission yr 2001, the problem with it is after a short while of driving it will suddenly shift from a fast gear to gear 1 and get stuck there, the revs will go up and naturally the car will slow down. After a few minutes of parking with the engine switched off and starting off again the car will shift gears ok for a short while before the situation starts all over again.
Initially I was told the transmission oil could be overheating so I changed the cooling system and transmision oil - it didnt work. Then I was told the transmission system could be faulty - I changed that too but the problem persists. The car was put on a diagnostics machine multiple times and it did not return any faults. what could be the problem?
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I see your question has been up for an extended time without a response. Do you still need help?

Customer: replied 4 years ago.

Yes I do.

What exact parts have been replaced?

Customer: replied 4 years ago.

the radiator,

the heat/temperature sensor

entire gearbox/transmission including the torque converter and ATF

Customer: replied 4 years ago.

the radiator,

the heat/temperature sensor

entire gearbox/transmission including the torque converter and ATF


NB. When I changed the transmission I used the same old speed sensor. this is the only component I re-used

Was the replacement transmission remanufactured, used or new?

Customer: replied 4 years ago.



Since the transmission was used it's possible that it also has internal problems, whether hydraulic or electrical. If the symptoms are exactly the same as before the trans was replaced though this isn't as likely.

If the problem seems to happen after driving for a while it's definitely possible that the trans could be overeating. Was the cooler flow checked? I would either monitor trans fluid temperature with a scan tool while it's acting up or flush and flow check the cooler to make sure it's not restricted.

If the cooler is ok and the symptoms are exactly the same with the replacement trans then it sounds likely the problem is electrical, either a wiring issue between the trans and transmission control module (TCM) or the TCM itself. The trans is fully electrically controlled by the TCM, the TCM controls all up and downshifting. It's possible that the TCM is failing and causing this, especially if no fault codes are setting in the TCM when this happens. Make sure too that when you are checking for fault codes you are going into the TCM with your scan tool, if you're not entering the TCM when looking for codes then there may be some there that will aid in diagnosis.
Customer: replied 4 years ago.

Thank you for your response.

I will have it re-checked based on the advise you have offered.

Please clarify when you say transmission could be overheating. What should cool the transmission? In my understanding hot ATF is cooled once it goes through the radiator and back into the trans, right? This is the reason I had it replaced with a bigger capacity higher performance New radiator when we suspected overheating.

Whereas I give benefit of doubt with the replacement trans being faulty as the first - I agree with you it is a highly unlikely coincidence - I bought if from a trusted dealer in Dubai. A problem with the TCM appears the most likely culprit - I will have it checked

Yes, the trans fluid is cooled in the transmission cooler in the radiator. It may also have an external auxiliary cooler. If the radiator has been replaced then you should be able to rule out a cooling issue.

With the radiator replaced and if it's doing the exact same thing as the last trans then I suspect you probably have a TCM issue.
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Customer: replied 4 years ago.



My mechanic has done further checks and he tells me the problem is with the speed sensor and not the TCM or Transmission. Where is the speed sensor located - is it part of the transmission?

I'm away from my service information at the moment, I'll get back to you with the location just as quick as I can!

Do you have a normal automatic transmission or is it a CVT?

Customer: replied 4 years ago.

normal automatic transmission

My service information does not cover this model and with extensive searching I have been unable to locate a diagram showing the speed sensor locations. Does the mechanic working on it not have service information for the vehicle?

There should be two speed sensors, an input and output speed sensor. They are three wire sensors, black, and they bolt to the outside of the transmission with a single bolt.