M45 Y34 RE5R05A transmission upgrades?

[HarvesterUT]

I've been reading through the forums looking for ways to make the M45 a little bit quicker, or at least not feel so sluggish when the transmission is up/down shifting. The Transgo shift kit seems like a worthwhile mod and will be something I do in the near future. What about TCU upgrades or swaps? Did I read somewhere that Infiniti/Nissan had updated software on the 2004 transmission to provide more responsive shifting? Did the 2005+ M45s get a revised TCU?

[Ilya]

I'm not sure how the Y34 would react, but a little bit of tuning from UpRev helped my 07 out a bit. That and I always drove in manual mode lol. Still do on my M56x.

[ArmedAviator]

TransGo kits increase line pressures to the point that seals and valves stay leaking pressures and this is bad for longevity. Bad idea. Programming is a better way to go. Depending on the programming, it may increase line pressures during shifts but does it in a different way.

The best method to firm up shifts is to increase fluid flow. This is generally done by increasing hole sizes in certain circuits on the valve body separator plate and changing spring tensions in the accumulators. I don't know of any instructions on doing this to Nissan transmission a to date. I've done it many times on Fords with great success (aka the J-mod).

[HarvesterUT]

The best method to firm up shifts is to increase fluid flow. This is generally done by increasing hole sizes in certain circuits on the valve body separator plate and changing spring tensions in the accumulators.

Isn't this what the TransGo kit does?

[ArmedAviator]

It does that plus other things, sometimes requiring drilling of the valve body itself (bad idea) or messing with the EPC solenoid (very had idea). Basically, all the "safe" steps can be accomplished with just a few drill bits and springs. You can get the springs separately for alot less as transmission parts stores.

I'd recommend you get a tune before any physical changes. You can always change the shift pressures back to stock or unflash the ECU. It's hard to go back and replace parts in the transmission.

FWIW, I did the spring change and separator plate drilling (a small number of holes be widened) a few years ago and 3 months later the transmission ate itself. In the aftermath it was discovered that one of the accumulators got slightly sideways on installation, tore the rubber gasket, leaked line pressure, and burnt the clutches in a matter of a few minutes once the gasket gave out as I was on a highway on ramp. I've done it many times before this, too.

[HarvesterUT]

I would totally do an ECU tune, but there are none available for the Y34. I've looked around, and only the 05+ M45's are supported. I believe the Y34 uses an older style ECU and no one has bothered to tune it.

[jspecusa]

technosquare tune Y34 ecu

[BlackCat81]

Contrary to popular belief, a shift kit is actually better for a trans. Firmer shifts equal less clutch slippage, which extends life and reduces heat build up. If you can mitigate the heat caused by the increased line pressure, you're golden.

[HarvesterUT]

Contrary to popular belief, a shift kit is actually better for a trans. Firmer shifts equal less clutch slippage, which extends life and reduces heat build up. If you can mitigate the heat caused by the increased line pressure, you're golden.

I was talking with my trusted mechanic, and he thinks these shift kits are fine to use. They should decrease torque converter slippage which will reduce heat build-up and increase fluid life. He also recommended installing a transmission fluid cooler.