Monday, June 9, 2014

New Gearbox Upgrade Project

This was never part of this year's mod plans but when an opportunity arises one doesn't think twice. Out of the blue I was notified by Bro Wallance that he possibly had a RS5F70A gearbox in possession. The pictures from Wallance confirmed this was indeed the 70A gearbox which is as you know pretty rare in this part of the world. Paid for the gearbox prompto and Wallance even helped deliver it. Thanks Bro. Gearbox had to be disassembled from the (QG18DE) engine it was mated to and Ah Tiong did the job.

BTW, if you ever wondered how Nissan designates its gearbox/trannies this is how it goes. The first two letters of "RS5F70A" indicate shifter location and "RS" means " Rear Shift". The "5" is pretty simple and means 5 forward gears. Please don't ask me why reverse gear is not counted. The "F" means "Front wheel drive" while "70" refers to the gear stack code. The last letter refers to the differential type. "A" is for open, "V" for viscous limited slip differential and "H" is for helical LSD type. Learned this from MotoIQ.

Pictures below of the 70A gearbox I bought.

Great condition eh? Certainly much better than the original from half-cut shop condition of my current 70A. There is minimal corrosion on the casing and even the fasteners look close to factory new!

So why another RS5F70A? As you know my current gearbox apart from the Nismo LSD has bone stock internals and is near or at it's durability/strength limit at my current engine torque and power levels. The plan therefore is to strengthen the stock gearbox internals. Nothing mega serious like straight cut gears with dog shifters or anything like that so please don't believe Jack :)

I however plan to disassemble the gearbox and send the gears, synchros, shift rods and forks, input shafts, final drive/ring gear and countershaft to the US for the following:

  1. Cryo treatment
  2. Shot peening 
  3. WPC treatment
The upgraded internals will then be send back to Bolehland for reassembly. 

The above treatments will hopefully increase the strength of the gearbox by 20-30% as well as reduce internal friction. The reduced internal friction will help keep the gearbox oil fresh longer as well as lower internal operating temperatures. Got poisoned by the excellent article @ MotoIQ. This sounds like a lot of work and money for the relatively small upgrade in strength and durability but please remember to check the price of a decent dog gearset and availability for the RS5F70A not to mention the major exponential increase in NVH. 

I'll update further in due time as we move along the project path which will take a couple months. As usual, please be patient. 

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