# P2837 transmission code - shift fork B - possible issue



## gtr mart (Mar 29, 2004)

I have a possible issue with my gearbox and would very much appreciate some guidance. 

*The problem:*
There have been two occasions within the last month where I have asked the car to change from 3rd to 2nd in manual and the gear indicator has blinked, the revs have dropped but then it has found the gear and all has been fine. Then within the last week there have been two further occasions where it's done the same but not found the gear in time and thrown code P2837 and put the car into limp and auto only. I have a Cobb so on both occasions I have been able to read and clear the code immediately. This makes me think it's more than just a glitch, noting I have never had this happen before. 



*I have two questions in particular:*
1) What are the causes of shift code P2837 Shift fork B? 
I have seen a few posts about it just being a glitch, although mine has happened a couple of times now so I think I have an issue. What are the causes of this? 

2) I had some gearbox work done last year and would like to understand what, if any interrelation there is between this possible new issue and that previous work performed (see spec below).



*Spec of my box:*
Car is a 2010 CBA running stage 4.25 but with torque capped to 590Lbft (647bhp)

2012 the following work was done (circa 30k miles):
Solonoid clean (under warranty)
First gear circlip fitted
Willall racing gear stoppers fitted (stop overselection)


Ran sweet as a nut, until in mid 2015 I broke a clutch basket and had the following work done (@ circa 56k miles)
Dodson billet clutch basket B
Of the two main tranny filters, one was replaced and one was cleaned and refitted
I proactivly opted to have the solonoid packs cleaned
I also had the solonoid clips fitted
I also had uprated dodson magnets fitted

For info only, in december I had the 60k service performed and my bellhousing changed.


As far as I was concerned with the above work done and the type of driving I tend to do, I was thinking my box should be reliable. I put the car to hibernate with no problems and it's only having got it out now that it is doing this. 


So if anyone can help with one or both of the above questions I would appreciate it.


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## Chronos (Dec 2, 2013)

I've had similar issue's http://www.gtr.co.uk/forum/344713-g...sues-3-clutches-acspeedtechs-cure-pics-2.html , so i'd say ring acspeedtech and they will be able to advise, as they know the gearbox's inside out!

From memory I remember mine was as it felt 'dropping out' of gear the revs would drop, then it would then select the gear, and i think* it was clutch related.. But before that issue i did have worn selectors forks as well, which are now upgraded and it's fine.

As i learnt from my experience, and advise that if it happens randomly say once every 6 months, generally its ok just a glitch, if its happening 2+ times per week or regularly, get it looked at *ASAP*, otherwise it may be causing more wear as mine was, and you will have a much bigger bill like it did, due to having more damage.


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## gtr mart (Mar 29, 2004)

Yes I read your threads with a sickening feeling to be honest.

I hope the selector fork is ok as I have had gear stops fitted (by AC Speedtech) back in 2012. These limit overselection so should reduce / stop wear and excess stress on the forks. Well that's the theory anyway!


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## Evo9lution (Aug 24, 2013)

Martin, give the guys at AC Speedtech a shout ASAP. It may put your mind at rest or at least you can get it booked in to be looked at.


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## terry lloyd (Feb 12, 2014)

Hi Martin - my worst night mare (gearbox issues) - have you tried a simple gear learn guessing you have a nis006 accessport ?


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## AdnanK (Jun 11, 2013)

AC guys know these boxes inside out and come highly recommended from other members, I wouldn't take it anywhere else.

Hope you get sorted mate.


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## gtr mart (Mar 29, 2004)

adanK said:


> AC guys know these boxes inside out and come highly recommended from other members, I wouldn't take it anywhere else.
> 
> Hope you get sorted mate.






Evo9lution said:


> Martin, give the guys at AC Speedtech a shout ASAP. It may put your mind at rest or at least you can get it booked in to be looked at.



Andy and the guys know the car and I am tempted but need to understand a little more before I start engaging with people.


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## gtr mart (Mar 29, 2004)

terry lloyd said:


> Hi Martin - my worst night mare (gearbox issues) - have you tried a simple gear learn guessing you have a nis006 accessport ?



Yea tell me about it Terry, particularly on the back of the work done last year.

Good idea on the gear learn. I will give that a try when I get the car out again. 

The clutches were all inspected on the B side and signed off as ok, I would assume a gear / clutch learn would have been done after that..?!


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## terry lloyd (Feb 12, 2014)

gtr mart said:


> Yea tell me about it Terry, particularly on the back of the work done last year.
> 
> Good idea on the gear learn. I will give that a try when I get the car out again.
> 
> The clutches were all inspected on the B side and signed off as ok, I would assume a gear / clutch learn would have been done after that..?!


More than likely they did a clutch learn after the work mate but its free to do and worth a shot - fingers crossed - if that did not work i would try a different gearbox map ( maybe a glitch ) and if no joy its a job for the experts


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## Stealth69 (Jan 6, 2005)

A gearbox relearn will have been done when the gearbox went back in your car but that was 3-4 years ago mate, things wear, stretch, get a little out of kilter, defo do a relearn, see how you fair and if it happens again get to ACSpeedtech as its all good trying to understand before you speak to anyone but you are going to go around in circles, all anyone can tell you is what they know of the fault, and it will always be the same thing.


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## gtr mart (Mar 29, 2004)

The box was open and the B clutch/basket was out during the middle of last year so it's a recent thing. I will deffo do the relearn and also try one of the previous Gbox maps.

It's a sensible approach to learn a little more about possible causes of failure otherwise you have no choice but to just leave your cheque book in the car when you drop it off. 

With tranny failures, as you say, you often cant be certain of the cause until you actually see it.

However, if the consensus is that of the 3 or 4 different reasons for the code will result in a range of fixes that could just include a sensor change or something then great I will be going to a specialist right here.

If however all of the 3 or 4 different reasons will require the box out and stuff to be taken apart (meaning the price will be thousands) then I have in mind to just take the box out myself and send it to SHEP or JACKS transmission for one of their 900HP drag builds which in the grand scheme of things is not much more money than doing it in the UK, but of course will take more time and means I will have to get my hands dirty. 

That last paragraph is irrelelevant to this thread though and I'm not looking to debate options yet - I just want to feel the range / gravity of the situation I am in.

I have my fingers crossed it wont be major. Turbos surely have to come before the box LOL

Keen for any answers to the two questions if people know?

Thanks for all the input so far - very much appreciated :thumbsup:


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## AdnanK (Jun 11, 2013)

See if the post in the end might shed some light?

P2837 - Transmission & Drivetrain - GT-R Life


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## rob2005 (Apr 26, 2015)

The thing is, where do you draw the line with these cars.

Mines on its way up to AC Speedtech as I type this and im expecting a bit of a bill as I have an issue where 1 in every 10 times i select 1st gear it wont select and the same for reverse it just flashes etc. 

I know my bill may be steep and after owning my car a year and spending £7-£9k in servicing, tyres, brakes, upgrades etc but where do you stop.

My goal like you Mart is a strong and reliable car and I don't mind spending but Jeez these can eat money and take the fun out of ownership.

As above I'm sure I would start with a clutch learn first but as you've thrown up a code I doubt its as simple. I'm sure Andy and Alan will look after you in any case.


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## gtr mart (Mar 29, 2004)

AdnanK said:


> See if the post in the end might shed some light?
> 
> P2837 - Transmission & Drivetrain - GT-R Life



Yes I had read that, the guy said:



someguy on gtrlife said:


> Hi guys, manage to solve the issue by running consult 3 to determine a hydraulic imbalance at the valve body trans fluid. Upon checking, all the filters and lines are choked with debris. After new filters, actuators, gear stoppers and some other stuff put in followed by continuous purging, problem is solved. No limp mode whatsoever.



This is why I am keen to understand the above two questions I have posed, as I had the filters cleaned/replaced, fluid changed, solonoids swept/cleaned, piston / solonoid clips fitted, stronger magnets installed and already have gear stoppers - so it surprises me that this could be the problem, even though the fix id probably the cheapest.

So blocked filters is one cause 

What else? Any chance of cracked gears / missing teeth on anything?


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## ACspeedtech (Aug 25, 2011)

Hi Mart,

The common issue with the GR6 trans is that about 8 different faults can all show themselves in the same manner which is why peoples 'fixes' can vary so greatly. We are usually able to deduce the more exact cause with a quick chat which circles around servicing/ mileage/ usage/ who or what work has been done before/ what code(s) appear at what frequency/ the circumstances of the trigger. With this info we're pretty successful at pinning it down somewhat but at your car's age/mileage I've a fairly good idea and can advise on a sensible plan moving forwards to minimise unneeded spending, if you give us a call tomorrow we'll happily talk you through it. Fingers crossed it's a minor issue!
Cheers!

Andy


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## dtox (Sep 21, 2009)

I spoke to Alan from AC Speedtech as my box has gone bang but hopefully my warrenty will be covering it and sending it to them. They don't try selling you bits and do give honest opionion. I would actually recommend them. Speak to Andy/Alan tomorrow - Not delt with Andy but Alan I can only speak highly of.

My box may even be next to yours ha ha... At least you had a fault code mine just want no bangs no codes nothing.... deadly silence..


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## Tinyflier (Jun 13, 2012)

ACSpeedtech rebuilt mine recently (R-1-R shift errors) and a more pleasant and helpful bunch of guys you could never meet.

Luckily for me was all covered under warranty. 

Needless to say tranny has been perfectly behaved since and Andy spent extra time explain how I can upload next gen software and perform clutch re-learns.

David.


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## Chronos (Dec 2, 2013)

Tinyflier said:


> ACSpeedtech rebuilt mine recently (R-1-R shift errors) and a more pleasant and helpful bunch of guys you could never meet.
> Luckily for me was all covered under warranty.
> Needless to say tranny has been perfectly behaved since and Andy spent extra time explain how I can upload next gen software and perform clutch re-learns.
> David.



Which warranty do you have?? mines due up soon with warrantywise, and wouldn't mind a better more *trustworthy* and not trying to *wriggle out of everything* one.

thanks


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## AdnanK (Jun 11, 2013)

dtox said:


> I spoke to Alan from AC Speedtech as my box has gone bang but hopefully my warrenty will be covering it and sending it to them. They don't try selling you bits and do give honest opionion. I would actually recommend them. Speak to Andy/Alan tomorrow - Not delt with Andy but Alan I can only speak highly of.
> 
> My box may even be next to yours ha ha... At least you had a fault code mine just want no bangs no codes nothing.... deadly silence..


Sorry to hear that, hope you get it sorted. Is this AC Speedtech's own warranty?


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## AdnanK (Jun 11, 2013)

Chronos said:


> Which warranty do you have?? mines due up soon with warrantywise, and wouldn't mind a better more *trustworthy* and not trying to *wriggle out of everything* one.
> 
> thanks


Defo go for a tuner one mate. I may be tempted with AC Speedtech's warranty once my OEM expires. They seem to be spot on with their customer service which is a massive plus.


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## matthewk (Aug 22, 2013)

This is what its like when it happens on track Martin, for me it was very intermittent until I got on track and then it would do it a lot until the car got warmed up well. 




That's an upshift 3rd to 4th, it also did it coming down the box.


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## Tinyflier (Jun 13, 2012)

Chronos said:


> Which warranty do you have?? mines due up soon with warrantywise, and wouldn't mind a better more *trustworthy* and not trying to *wriggle out of everything* one.
> 
> thanks


Was from Auto Direct, supplied by the dealer I bought car from. Was a very rare "Wear & Tear" coverage which even the engineer who was sent to "inspect*" the stripped out tranny said was highly unusual. I think it was an error by the dealer but I was not complaining!

Gave the company ZERO wiggle room BUT their invitation to renew was a standard non Wear & Tear cover policy - which I did not take up.

Likely to go to AutoTorque for cover - their policy seems pretty decent.

*Regarding the "inspection" carried out by the warranty engineer - Andy at ACSpeedtech said it was the usual situation - engineer arrives, looks bemused at a pile of parts, shakes head and goes off in a mood as he couldn't work out how it all fitted together!

David


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## terry lloyd (Feb 12, 2014)

Would those who have had faults be willing to to say what the problem / cure was and roughly how much it cost to fix so others will have a idea what to expect if they had issues in the future .


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## Chronos (Dec 2, 2013)

AdnanK said:


> Defo go for a tuner one mate. I may be tempted with AC Speedtech's warranty once my OEM expires. They seem to be spot on with their customer service which is a massive plus.


ACspeedtech do a warranty now? I didnt know that.. Or I'd have one signed up. will give them a buzz. thanks.



Tinyflier said:


> Was from Auto Direct, supplied by the dealer I bought car from. Was a very rare "Wear & Tear" coverage which even the engineer who was sent to "inspect*" the stripped out tranny said was highly unusual. I think it was an error by the dealer but I was not complaining!
> Gave the company ZERO wiggle room BUT their invitation to renew was a standard non Wear & Tear cover policy - which I did not take up.
> Likely to go to AutoTorque for cover - their policy seems pretty decent.
> *Regarding the "inspection" carried out by the warranty engineer - Andy at ACSpeedtech said it was the usual situation - engineer arrives, looks bemused at a pile of parts, shakes head and goes off in a mood as he couldn't work out how it all fitted together!
> David


thanks bud, I tried a claim with warrantywise on the dash leds, and they wriggled out of it.. I get the impression that's the normal process, wriggly worms!



terry lloyd said:


> Would those who have had faults be willing to to say what the problem / cure was and roughly how much it cost to fix so others will have a idea what to expect if they had issues in the future .


you can get some idea below , i put the work/faults/costs. http://www.gtr.co.uk/forum/344713-g...issues-3-clutches-acspeedtechs-cure-pics.html


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## rob2005 (Apr 26, 2015)

Chronos I've read your post a few times now and while i have a budget in mind for my box with a very intermittent 1st/R issue if mine costs £7-10K I may be suicidal :chuckle::chuckle:

Hows the box been since the overhaul?


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## Chronos (Dec 2, 2013)

rob2005 said:


> Chronos I've read your post a few times now and while i have a budget in mind for my box with a very intermittent 1st/R issue if mine costs £7-10K I may be suicidal :chuckle::chuckle:
> Hows the box been since the overhaul?


Well that's how mine started, intermittent 1st/R issue .. i left it a bit too long, and it caused wear on other components, which made everything worse! You live and learn and pay!... my advice is, if it's doing it regularly 1-2+ times per week, and you have done a clutch learn etc, get it into your tuner ASAP to be sorted. 

Box has been just dandy, It feels very strong and has done 3 trackdays and its been over 12 months i think now and over 14,000 miles!, Initially it was slightly smoother with the Dodson gear in it and stock clutch, then i had to go 16 plate clutch due to the hill situation, and now the changes are a lot more aggressive and can bang in even at low revs, which TBh can get annoying!! BUT I have to live with it, it's either that OR take a plate out and the clutch will go smoother again, but won't last on the stupid hill OR sell the car, which aint going to happen it's too much fun!! However as it's upgraded it can handle 800lbft torque, plus the gearbox will be stronger with the dodson kit, So is ready for upgrades.. yum yum!! aka turbos and the likes. sound's like an excuse to me! *checks pennies in the bank..*


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## rob2005 (Apr 26, 2015)

It was your post and many other recommendations tat made me choose AC Speedtech and it arrived with them yesterday 

You've got no excuses now then, get some larger turbos to help you get up that hill


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## Litchfield (Feb 26, 2008)

Martin, I would expect your problem to be related to the fact we found Syncro teeth in the gearbox when we repaired the clutch basket. We just cleaned these out at you request. I would imagine next series of teeth are on their way out now and that is hindering the gear change.


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## AdnanK (Jun 11, 2013)

Chronos said:


> ...its been over 12 months i think now and over 14,000 miles!..


Whattttt! 14k miles in a year. How many miles do you have on her?


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## Chronos (Dec 2, 2013)

AdnanK said:


> Whattttt! 14k miles in a year. How many miles do you have on her?


about 53k now, and what fun it's been :clap::thumbsup:


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## AdnanK (Jun 11, 2013)

Chronos said:


> about 53k now, and what fun it's been :clap::thumbsup:


Good going, you can take comfort from the 100k miler GTR we have on here.


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## Chronos (Dec 2, 2013)

AdnanK said:


> Good going, you can take comfort from the 100k miler GTR we have on here.


Yeah it certainly Shows how hard wearing and generally reliable the R35 GT-R is, I think He's on like 120k miles now! epic!


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