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Beefing up you Auto Transmission

I found this article made very interesting reading, and so I have published it here with permission from Rodney...

Automatic Transmission Tech Talk & Development
Rodney Hudson-Davies

Hi my name is Rodney Hudson-Davies and I am in charge of the Technical, Development and Motorsports department within Wholesale Automatic Transmissions. I have put together an article about some items that our company has been developing and testing over the past 3-4 years in the hope that at the very least would make for some very interesting reading for all Patrol and Landcruiser owners that have an automatic transmissions fitted. We have been developing and testing a few items that have been fitted to dozens of 4 wheel drives including Nissan Patrols and Toyota Landcruisers. Please take the time to read on and feel free contact me about any questions that the members might have. Regards: Rodney

Our Extreme Recalibrated changeover valve bodies have not only been designed for all V8 conversions but also for all Turbo Charged, Super Charged and also for anybody including ourselves that wanted a sharper and more satisfying shift feel. Our valve bodies have been recalibrated to solve other problems such as Soft Shift Feel, Kick Down Flare, Overheating and transmission failure due to heat produced by Lock Up Slippage, Overall Transmission Pressures and Clutch Clamping Force. Our new release Nissan Patrol and Toyota Landcruiser valve bodies make all the difference. Often we hear owners constantly complaining about the quality of their Nissan Automatic Transmission when shifting through the gears, most come from everyday drivers who simply can't stand the constant slipping and flaring between the gears. We have had dozens of owners contact us about improving the transmission in some way to overcome the problem. We put together a development program and have come up with a cheap and easy way to turn both the Nissan Patrol and Toyota transmissions into nice firm shifting transmissions without having to remove the transmission from the car, Simply remove the valve body and exchange it for one of our Stage II Recalibrated Extreme Valve Bodies.

The valve bodies comes with easy to read instructions for the removal and refitting of the new valve body. The valve body has undergone a tremendous amount of testing including thous that have had Turbo Chargers, Super Chargers and even large V8 Conversions done and in every single case the customer has been quite overwhelmed about the difference the New Valve Body made to the vehicle.

The transmission once fitted with the new valve body can easily handle more than twice the power and torque with nice firm shift points even while towing trailers that are of considerable weight. The New Valve Body has also been tested behind large V8 engines including the 6.5 litre Chevy diesel V8, We simply couldn't fault the new Extreme Recalibrated Stage II Valve Body no matter what we did to it ( At time of print the valve body had been tested to 607Hp = 450Kw without failure to the transmission).

Our New Extreme Stage II Recalibrated Heavy Duty Nissan Patrol Valve Body

The New Set Of Solenoids Used On Our Extreme Nissan Valve Bodies

One Of The Modifications Made Is To This Accumulator

After 2 years of trial and error we have also finally managed to find a way to lower the convertor stall speed of the RE4RO3A Nissan Patrol, A440F, A442F, A343 and A750 Toyota Landcruisers. We have found that this is a must before any V8 conversion is considered as using the standard convertor behind any V8 engine turns the convertor into an instant high stall. This will generate so much heat when the lock up is not engaged that the life expectancy of the transmission in many cases have been recorded on a regular basis to be as low as 100km with most transmissions lost at 5000km. You simply CAN NOT do a V8 conversion without altering the convertor.

We have seen many modifications made from all over the world to solve this problem ranging from fancy large oil coolers, different types of oil, valve body modifications and some have tried to lower the stall speed but could only drop the stall speed on average from 2400-2000Rpm. We also went down these same roads and came across the same problems as most others had before us but we persisted for 2 long years until we finally and almost by accident in one case solved the problems one by one. We now have a Super Low Stall Convertor that we have managed to lower from an average 2400-1200Rpm solving the overheating problem caused by stall speed. We have also received ALOT!! of positive feedback about far greater engine braking reducing down hill braking by as much as 80%, Increased low to mid range torque for those never ending hills and highway cruising even while towing and a noticeable reduction in fuel usage.

Please note that when we designed this convertor we were trying to get rid of the overheating problem and have received reports from almost EVERY customer about better engine braking, notably better Fuel economy and far greater low - mid range engine torque. We never tested for these things and these reports have come from all over the world after many thousands of Kilometres of driving, Most While Towing!

All Our Toyota and Nissan Super Low Stall Convertors Come Kilm Bronzed And Micro Balanced

We have also found that using full Synthetic transmission oils will lower the overall transmission temperature even further by a small amount and is also engineered to remain stable under the most severe conditions. We use Castrol "Transmax-z" but have also found that all Allison Transmission dealers have a product called "TranSynd" while Amsoil also have "ATF" and "ATD". All of these automatic transmission oils have one thing in common and that is that they are all Full Synthetic. They will NOT replace the need for a super low stall convertor or Extreme valve body but if you want that added edge on overall reliability then this is it.

We also don't discount a good oil cooler as we always will recommend a suitable cooler in any vehicle that runs a transmission. The transmission life span is mostly measured in heat, the hotter the transmission runs the shorter the life expectancy while the closer you can get your transmission to run at room temperature then your transmission is expected to last what is considered in repairers terms as a life time 350,000-500,000Km depending on usage and other unforseen factors. A good cooler is the cross flow type as there slow the oil speed down considerably while within the cooler which inturn keeps the oil within the cooler for a much greater length of time while the "S" pipe type oil coolers don't slow the oils speed what so ever! Please remember that oil coolers are a science in themselves, for example the thickness of the cooler is nowhere as important as the overall size Height x Width. The greater the surface area the greater the cooling, if you double the surface area then you have doubled the cooler efficiency but if you double the thickness of the cooler the cooler will only improve by 10-15%. Dont' worry it took me 20 years as a transmission rebuilder to figure out what a radiator repairer will learn in their first year as an apprentice!

I DON'T recommend that any of these changes are made while your Nissan is under NEW car warranty as im sure "without checking" that the wording within your warranty policy would not leave itself open to these changes except for possibly the oil cooler. And don't forget that we are here to help and look forward to hearing from anyone that has a question or maybe some information about an experience or a product, after all we are always looking for new ways to improve our development programs.

Look Forward To Hearing From You.

Rodney Hudson-Davies
Wholesale Automatic Transmissions
Factory 1/58 Barry Street
Victoria 3153
Phone (03) 97628004
Mobile 0415 393755

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This page was last updated on 13 Jan 2004