For over 10 years now Garage-D has been maintaining and upgrading the S15 6 speed gearboxes. With the knowledge we’ve accumulated over the years we have discovered the various issues these gearboxes face and what can be done to fix and keep them reliable.
The first general sign of S15 gearbox troubles is 3rd and 4th gears becoming difficult to select, this is a result of the locating circlip on the layshaft coming away and allowing the gears to move when trying to select gear. As these move they cause damage which shortly leads to terminal failure, which renders the gearbox scrap.
Using a leading gearbox manufacturer, we modify the layshaft and upgrade the circlip to a locking collar type of location as generally would be used in other high performance gearboxes.
We have noticed that even on low mileage virgin cars that the 6 speed box may commonly suffer from a noisy input shaft, people have thought their gearbox was on its way out when they start to hear a slight whine when their foot is off the clutch pedal but disappears when the clutch pedal is pressed down. This doesn’t affect reliability as it generally is down to the fact that these boxes are designed for a lighter grade of oil and a dual mass flywheel which many people replace for a solid version.
It is worth noting that our S15 gearbox modification is more of a preventive modification rather than a strength upgrade. S15 gearboxes generally fail from a combination of mileage and gear shifts rather than overall power, however heading towards 400bhp (flywheel) it is the combination of torque and clutch choice that will lead to gear failure which again renders the gearbox scrap. From here we recommend the Garage-D bolt in Nissan Skyline RB25 gearbox conversion which we can also supply all parts for including adapter kit - https://garage-d.com/sr-rb-gearbox-adaptor-plate.html
General lead time to carry out this modification to your S15 gearbox is 2-4 weeks. When being done, we fully inspect the complete gearbox so should you have any other issues (synchro etc), this can be addressed at the same time.
Alternatively, we do stock gearboxes with this modification already carried out, however we only do these on a supply and fit basis taking your old gearbox in exchange. This is to ensure the gearbox we are taking in exchange is in good order and that the replacement gearbox is fitted correctly.
Pricing starts from just £495 +vat. Contact us for more information.
As a fully equipped workshop, we offer a fitting service on all of these options, please enquire for further details.
We also carry in stock:
- A wide range of clutch kits
- Our recommended gearbox oil
- Replacement / upgraded engine and gearbox mounts
- 1000’s of other new and used Nissan Silvia parts
This super clean 180SX had just been assembled and come out of the paint booth a day before it made the trip up to us for a full alignment setup.
As most of the car had only recently been bolted back together we wanted to add finishing mechanical touches to ensure everything was safe and sound before any serious road / track use.
This car has a huge spec list inside and out and features some of our own products such as our SR > RB Gearbox Adaptor plate which allows the car to run an RB25DET gearbox. Ideal for handling the extra power from it's forged SR20DET engine.
In these times of mass social media and a shift towards Youtube videos, simple blogs are sometimes seen as old fashioned, however we have decided to start a blog again as a good way of showing what we do but in a format that is easy to find and look back on. We’ll aim to bring you useful technical articles, project updates, and news about products and events.
After 12 years in our old Watford unit and outgrowing it in many ways, we moved to our current Berkhamsted unit in 2019. Being an empty shell it was a challenge to set up shop again however this was actually a blessing as it meant we could lay out the workshop exactly how we wanted.
Within 3 months we were back up and running with a dedicated engine building room, differential and gearbox assembly areas, organised storage for our huge stock of new and used parts, two ramps in the main workshop and separate fabrication bay with additional ramps. This was finished off with some wall art, initially created by ‘Queen B’ Becky Evans doing donuts on the BBC One show outside the BBC building in London.
This is still and always will be a work in progress, and phase two of the build will finally see us with an in house dyno. Keep an eye out for more updates when this is done.
For now, we just want to say a big thanks to all our customers and suppliers that helped and supported us during our move and we look forward to seeing you at Garage-D 2.0 sometime soon!