GTR Forum banner

1 - 7 of 7 Posts

·
Vendor
Joined
·
490 Posts
Discussion Starter #1 (Edited)
R35 GTR Transmission Upgrades

The GR6 transmission, although very strong and capable does have a few issues. We have available upgrade parts from ACspeedtech that can prevent and repair the minor problems that account for around 99% of the issues that trigger various transmission faults:

Front Circlip retainer

Well noted is the issue with the front circlip either coming adrift from the circlip groove or with the repeated shock loading actually wiping the whole groove off the end of the shaft leaving no possibility of holding a circlip on at all. There are quite a few designs of retaining the circlip, the design we use covers the circlip stopping it from opening up, but also clamps into the end of the shaft re-enforcing it and preventing total damage to the circlip groove itself. It is also 'balanced' and will not cause any issues with vibration/resonance that may occur with some 'clamp' designs and also does not rely on the existing circlip groove which we have seen failure of. To date we have not seen failure of any of the other circlips in road or circuit use, so we cannot recommend upgrade of them. Requires transmission removal to fit. RRP £100+vat per car set

Gear stopper kits

Over selection of the gear by the shift forks repeatedly impacts the sleeve on the stops on the gear. Fitting this kit repairs issues with and prevents further damage to the stops by limiting the shift fork travel. Made from a specific nylon designed and tested to be impervious to the aggresive transmission fluid. As a nice by-product, the nylon also feels to dampen and smooth the shift too over the factory metal-to-metal setup. Fitted into the solenoid pack without transmission removal. RRP £150+vat per car set
IMAG1894.jpg

Piston clips

As the shift forks are actuated by the shift pistons, the square edges of the shift piston wear off, this allows the piston to rotate which in turn allows the magnets in them to rotate which then go out of range of the mag sensor and the TCU cannot 'see' where the shift piston is triggering a fault. These piston clips work by increasing the size of the locating area stopping the piston from rotating and solving the issue. They are also made from steel which will not wear the same as the soft alloy shift piston stopping future issues. The design is similar to the factory Nissan upgrade which unfortunately is NOT available to the end user from their parts departments. There is another design available which is formed from simple steel channel which we bypassed due to it's poor retention ability. Fitted into the solenoid pack without transmission removal. RRP £80+vat per car set
IMAG1895.jpg

GR6 Upgrade Kit

We can supply these kits individually, or can supply as a kit with all 3 of these parts to prevent and repair against the vast majority of issues you may find with this transmission in a 'per car kit'. OFFER PRICE £288.75+vat

IMAG1893.jpg

This is available with just the Piston Clip Kit and the Gear Stopper Kit for an OFFER PRICE of £201.25+vat

We can also supply the Pentosin FFL-4 or FFL-R in 10 litre containers for individual per-car servicing/upgrades.

We find that these transmissions create quite a lot of debris during the first few thousand miles of use which can clog up the magnets in the sump pan. The first time the pan is removed will look the worst, after the first clean, you won't see the same levels of deposits on the magnets if examined at a later date.
 

·
Registered
Joined
·
798 Posts
Good prices, well worth doing gives me something to think about when my car comes out of hybernation :)
 

·
Vendor
Joined
·
490 Posts
Discussion Starter #3
Thank you :) We make the upgraded parts ourselves so keeps the cost down for everyone. Gear stoppers and Piston clips are a common upgrade to be done at service time while the transmission fluid is being dropped already.

Coming soon will be upgraded shift forks, available individually (i.e. replace the troublesome 1st/reverse snapped one) or a full upgraded set. Will bring a much firmer and reliable shift feel as well. That should complete the catalogue for fixing/repairing/prevention of issues with these transmissions.
 

·
Registered
Joined
·
2,538 Posts
Would like to know a bit more about gearbox filters, can see that a couple of companies offer filter upgrades and have seen some threads talking about cleaning the gearbox filters.

Is there a good source for the available options?

Thanks

Hugh
 
1 - 7 of 7 Posts
Top