GRX 5spd Auto - need help!

[David]

I am experiencing a thud from the gearbox when it selects 1st gear at a stop!

It doesn't do it all the time and it seems to be worse when the aircon is on (slightly higher revs...). I slow down and stop but when I take my foot from the brake the gearbox engages with a solid thud. The oil levels are fine and the oil doesn't look dirty

All other gear selections are fine. The Trol has only done 75k Km and was serviced by the agents on 60k Km for what thats worth!

I have never driven another tiptronic Patrol - nevermind an automatic - Is this common to other Patrols or am I starting to worry about things that don't need worrying about?

[Russ Kellermann]

just take it to Nissan dealership and ask whats going on. Alert them to the problem right away and they must find a solution (forum members: please leave out jokes and laughter here).

Its clearly still under warranty so i wouldnt worry.

[David]

Its clearly still under warranty so i wouldnt worry.

Nope - on age the warranty expired (100 thousand km or 3 years if I am correct) and since I bought it second hand I don't know if it was abused with a heavy trailer etc.
Thanks for the reply Russ! From the lack of any other replies I would gather that the thud is not common to other Patrols with the auto box. I don't think it is very serious but I am worried that it might cause longterm damage Maybe Nissan can change the parameters of the TCU to be more subtle?

It is just a bit of a slep to go to Nissan as there are no dealer in Stellenbosch and these guys don't work on weekends. However - I have to go pick up my Jumbo Tourer extension for my Hannibal rooftop tent in Epping Industria somewhere this week so might as well pop in by Nissan and see if anybody talks sense

[Russ Kellermann]

oh i see, didnt pick up on the '06 manufacture. Ok. Shit. Well, its still very low milage and i would at least try put it past nissan to sort it out Gratis. Afterall, it is a very expensive model and top and spec. I'd try them and see what they say, you never know. if it IS a problem, get hold of nisssan via written word to one of the top dogs and see what reply they may have, the details are on this forum somewhere. (ie:chain of command)

Let us know what happens either way alright, but dont give up. rather know what the noise is and be at peace with it, than worry every time you head 100km away from your house.

[tour de frans]

Good day.
Again, what agents? ,this is no joke,they sent their auto's to a outside workshop,witch are no Nissan dealer.
Go to Allen @ Triangle Transmission in Parow.
Rgds
Frans

[JG Shields]

David,

I am not sure what exactly you mean by a "thud".

1. Have you checked the universals on the propshaft?

2. The 4.8 gearbox has a filter inside the valve body. It is possible that the filter is blocked. It can be replaced.

3. Have you "jump started" the vehicle recently? This is a common cause of TCM problems with the Nissan, BMW, Volvo and Toyota auto boxes.

Never the less, Mayfair Auto is the official repair agents for all the Nissan auto gearboxes. Save your breath with Nissan and go directly to Mayfair to do a diagnosis on your gearbox. My experience with them is very good and I am sure they will sort you our in no time. Just Google their nearest branch contact details. The 4.8 Patrol uses the JATCO RE5R05A gearbox. It is a 9 solenoid valve gearbox and is more complex than most other auto boxes around, yet is is an almost indestructable gearbox.

My gut feeling is that you have a small problem. However, Nissan will make a big issue (and cost) about it.

[David]

Thanks for the info! I agree totally with skipping the agents for identifying the problem

The thud is similar to letting go of the clutch too fast on a manual - only slightly less aggressive as I am not giving it gas - but it doesn't happen all the time which is weird.

If I stop in 'D' and take my foot from the brake the car will move forward which is normal as far as I know.

It seems like the resistance of the brake will stop it from selecting first gear and that it only selects first when I let go of the brake - and then it makes the 'thud'.

I have checked my universals and they have no play.

The filter might be an option as I don't know if the gearbox oil have been changed for some reason. Might be a good time to have it serviced even though the oil still 'looks' good.

I have never had the need to jumpstart the car so I don't think it is that.

I see Mayfair's Cape branch is at 17c Killarney Avenue, Killarney Gardens, Cape Town - Telephone No : 021 556 7685 and also heard a lot of good about Allen @ Triangle Transmissions.

Thanks for your inputs

[JG Shields]

Good luck David. Please let me know of the outcome.

[AdrianPowrie]

Hi David

Any news on the outcome of the problem that you had?

I have a 2003 4.8 auto which is doing EXACTLY the same thing...
All the three Nissan dealers that I have spoken to say that it is a normal Patrol thing or that the rear diff has an issue...

I have also check all universals and prop shafts and found them to be completey dry. Once properly greased the problem is still there, if a little worse..

I have dropped the vehicle off at the gearbox specialist that we use for all our truck and car gearbox services/repairs for him to open it up and check the filter & screen. So I am waiting now for a chance that it isnt a huge problem.

[David]

I did come to the conclusion that it is related to the idling speed.
When the air-con is on the fans are switched on automatically which ups the idling speed which then causes the thud
If I switch off the air-con then I have no thud - (I would appreciate it if you can test if this is the same with yours?)

The 4.8 has more than enough torque at idle to handle the addisional load without having to increase the idling speed so I am thinking the solution might be to stop the signal that prompts the ECU that there is a higher load. I just haven't had the time to try it ...