Hi guys! So I have Infiniti G35 AWD 2007 with biturbo kit from GTM with automatic transmission (RE5R05A). After turbo kit installation this transmission is being repaired for the 4th time (the previous owner of the car repaired it 3 times). I know that at this moment Transgo shift kit is installed. Also, I'm going to install a cooler. I ordered the full master rebuild kit (Raybestos) and some planetary for replacement. Now I'm stuck with the choice of ATF for my tranny. I read that someone suggested Amsoil but it is not available in my country (I live in Ukraine) and I don't want to wait several weeks for delivery. What do you suggest to use as ATF in my case? OEM Nissan Matic S because it is like "new and better" than J? My car manual suggests to use Nissan Matic J only but I'm confused...

 

It's all about the friction modifiers being used, you don't want smooth comfortable shifts when torque is killing your transmission. You want something grabby to keep those clutches alive for as long as possible.

How much torque is the engine making. If you're over 400 lbs I'd experiment with fluids to see how it behaves with different blends of fluid. If it's under 400 lbs of torque it's probably just dying due to overheated fluid. Definitely definitely definitely get a better cooler if the fluid is cooked. You'll know more when you drain everything out and inspect the clutches/brakes to see what exactly is failing. Put in a temperature gauge so you can monitor things in the future (might be able to use software to monitor the stock temp gauge, I don't know what it's range is though)

@scumbagsleeper has pretty extensive experience working with those autos and I'm sure he can shed more light into what needs to be done to reinforce weak spots.

 

If I used the correct converter then I have 373.94401 ft-lb (507 N-M in metric system and graphics attached). Now I understand that cooler IS A MUST and it will be installed 100%. "Put in a temperature gauge so you can monitor things in the future" - great advice, thanks! I will ask my service if they can do this.
Thanks for your answer!

 

If I used the correct converter then I have 373.94401 ft-lb (507 N-M in metric system and graphics attached). Now I understand that cooler IS A MUST and it will be installed 100%. "Put in a temperature gauge so you can monitor things in the future" - great advice, thanks! I will ask my service if they can do this.
Thanks for your answer!

 

You'll probably end up plumbing in a temp sensor in the cooler line. You install them in the hot side of the line, just did one on a Chevy truck last month. The tricky part is finding a clean-looking spot in the cabin to mount the gauge.

 

Nice curves on the graph....

 

On all of the SR20 Jatco transmissions that we have modified we have found cheap synthetic ATF works very well. I actually use Walmart Super Tech $16-$17 dollars a gallon in the G20 under 20psi. The tranny has held up for over 2 years at about 290 whp (car is about 125 whp stock) so over double what it's supposed to handle I rather use cheaper fluid and change it more often than spend $100 on exotic stuff. I haven't felt any difference in the regular dextron mercron III vs the synthetic. Unfortunately we found that at around 220-240whp on the RE4 starts to flex the internals and it looses pilot pressure so we have to lock up the torque converter manually at 10psi so we can push it harder haha more power locked up anyway... So with the RE4's pretty much at it's limit without dumping major $$$ to go faster I moved to the RE5's.which are absolutely monstrous compared to the older stuff.

The things that will make your transmission hold up when you are rebuilding it is to get more friction and steel discs fit in there. The service manual has all of the measurements to gap them, but we have found they can be a little tighter gap for faster engagement, but too tight and they will cook / generate lots of heat. We had to burn up a couple transmissions so we could find the weak spots and then beef up the clutch packs and try again. Sometimes you can't just fit more in and have to machine the drum or top plate to make space for more. I do know there is carbon fiber clutches and some other special high temp type material clutches made but I haven't tried them and honestly with the torque of a turbo car just needs more surface area not better material in my opinion. I ran my 05' turbo car all last summer on the cheap Super Tech fluid too. Every Jatco I have been into is designed pretty much the same so I have always used the same fluid in all of them. I'm getting ready to dive into the 6 speed Jatco soon and am guessing they will probably be the same.

If I ever get time between things I would like to write up some of the RE5 findings. There are quite a few variants and swappable parts. Been tearing apart the two 5.6l and 4.5l variants and making a more bulletproof version with the steel baskets and already capable or more clutch / frictions than the cars. Also the 08' G37 coupe already has a HD version of the RE5 (last year of the RE5). It has the big output shaft and larger drums. Thinking the 07-08 cars may be this way too since the increase of HP and rev limit but have to get one apart to measure stuff.

If you get your 07' AWD tranny out and apart let me know. it's the one I haven't got into and would love to see a few things. We are building a 08' GTX3582r AWD car this summer, but will probably cook the tranny so we can find the weak spots.

 

Guys, thanks for replies! But what do you think about ATF with such properties:



As I understand, it will be more pressure inside tranny with the first one under 100°C, am I right?

 

So a little update. My transmission is ready and already installed. It was found during installation that AT cooler was ALREADY installed. So my hopes for additional cooling were broken. Idemitsu Type J (which is Nissan Matic J) was used as ATF. Not Nissan Matic S because I found that it was used in the past when tranny broke. Now I'm waiting for answer about high temp ATF which is described as

Anyway, any suggestions still would be helpful because here is ATF temperature after several non-agressive accelerations 60-250 km/h (outside temp was near 15°C or 59°F)

 

Honestly it's not overheating so... I mean it's at sort of the high end of where you want the fluid temp to be but considering the mods it's not terrible, just decrease your fluid change interval to 15-20k miles. You should add a temp gauge so you can watch it in the future though. Also, how big of an aftermarket cooler does it have?

The stock fluid temp probe is up inside the transmission, I suspect it's going to read a little hotter just because of where it's installed. See if some other users can post their transmission fluid temp to compare.

There's also nothing wrong with adding a second tranny cooler in series with the first, done it before on track cars using powerglides that needed the extra cooling but didn't have much room to install a bigger cooler.