Just read in the SAW Instruction manual confirmation of a max alarm setting of 110C (factory set 100C), the alarm consists of a flashing "H" no actual temperature display.
Hmmm ok, so this shouldn't be considered as an accurate measure? - I have set the alarm at 90, and seen mine spike to about 100, but thats with a decent drive.. - I have monitored it during a trip using the PC, and it gradually, but steadily increases until you stop.. What would be considered a 'maximum' temp, if this gauge is relatively inaccurate? - also does anyone know where this sensor is?
I had also always presumed that the torque converter used this temp gauge, as mine would never lockup if you hop straight on the open road on a cold motor, but after a few mins driving, temp rose, and torque converter would lockup? - is this related to the same sensor maybe?
Agree with you there. John, I took Nissan's stated temps of 50 ~ 80*C to mean that 50 was the minimum point to allow overdrive and lockup functions. They don't seem to state this in the FSM but I thought it was kind of logical. I'm about to start some testing with Conzult Tuner edition reading the ATCU to gather some data on the temps that the ATCU needs to see before it allows overdrive and lockup to work. ( If someone has already done this, please share and save me a bit of effort ) As for the upper figure of 80*C ? They don't seem to discuss temps higher than 80*C in the FSM. It's good for us auto Z32 owners that the Patrol and Maverick use the same transmissions. There's some good info to be had on their Forums. But I'm not yet convinced that reading the ATF temp as it leaves the transmission is the way to go. Serious 4 x 4's Jatcos are punished in different ways to ours
That 50-80C = HOT was taken from a more detailed workshop manual, there is not a lot more in there then the FSM but a few bits and pieces, it related specifically to reading fluid levels.
Yes, the TCU (Transmission Control Unit) takes TPS/RPM and ground speed from the ECU and also uses the trans temp sensor to set a threshold or 2, the TCU controls the solenoids in the transmission for gear shifts and limits the lockup until a temp is reached. The reason I doubt the accuracy of the trans temp sensor is that it uses 0.0167V per degree C, at 110 its looking for 0V at 100C its looking for 0.167V, bad earths and wire lengths are able to screw with this easily, let alone the accuracy of the sensor it self, the manual says "approximately" its not designed for this purpose, just to set a threshold or two. So is the 100C alarm useful, definitely, gives you a heads up, is it useful for running the transmission to the edge with out inadvertently skyrocketing the temps, no. To the average street driven car this all means zip, purely related to a high performance situation, I would love a SAW, if I had one I would definitely have a separate temp gauge so that I could make full use of it with out having to pull up early. I would also like one on my current setup with new fully rebuilt performance transmission and TC, mainly to see how high my temps are getting with a level of driving and see if I need an even bigger cooler to keep temps reasonable, to date I have taken it fairly easy with all this in the back of my mind. I have my cooler mounted high between the headlights behind the nose panel and have been working on a fully mesh nose panel, but I am slowly giving up on that and looking at the Stillen nose panel with 2 sets of 3 vertical slots opened up, it should do the job I reckon. For me i would be looking for a maximum temperature of 80-90C for straight driving and 110-115C whilst giving it a serve, but with the ability to bring it down fairly quickly once easing off, the only way to really get an idea whats happening is with a temperature gauge. I have a seat of the pants idea of how hot the trans is by how hot the shift plate with D-R-P-2 on it, on my previous trans I would lick my finger and fully expected it to go pssshhttt like and iron. It used to get bloody hot.
The kit was model specific for the transmission type on the 300ZX, are you running the RE4R01A or RE4R03A ? (Don't know if the filter or pan gasket are different between the two) When I had the tranny rebuilt, the shop recommended I use Transmax (Castrol?) but I told them I had always used Valvoline and they said no problems with that. I use Valvoline 95LE. With the track work I do, am still planning on changing tranny fluid twice a year and filter every 12 months.
wow guys, thanks heaps for all the info - this thread has brought out some seriously good replies.. As to which tranny I am running, I wouldn't have the foggiest, this is the most i've dealt with the a/t tranny since purchasing the car, but plan to get more of an insight into it all.. I can't particularly get under the car to identify the model i am running, although its a s2, which I'm not sure if it was a difference?
Was also just thinking - To manage temperatures using the stock cooler; is there anyway we could engage the stock aux fan to force some air through the rad / oil cooler? - or is this some silly thought I made up while still half asleep in bed?
If you have a stock NA then it will have the RE4R01A. The ID plate in front of the radiator (next to bonnet catch) will detail it.
The tranny fluid running through the radiator can't get enough cooling time. The oil temp stays a lot hotter than the coolant temp in the radiator. Running extra air through the radiator won't lower the tranny fluid temp. It needs the separate cooler's extra volume/cooling area to make the difference. As I said earlier, don't sweat too much about this in the short term as the tranny can handle oil temps of +140C, it just shortens the working life of the tranny fluid, so change the fluid twice a year until you install the extra cooler. My SAW kit oil temp warning only used to come on during track work or extended hard running through the gears on mountain winding roads. The warning light would go out after 5 minutes of idle down after a race.
