trannsmission flush coolant flush questions

[Tigerfan7777]

Hi all. Please help. I spoke with Infiniti today about my 2007 M35 base 2wd. It has 142,000 miles. I believe the transmission was flushed at 90 k and maybe the coolant was too. The previous owner performed what Infiniti calls the 90k service where the transmission was flushed and again, maybe the coolant system. Car has seen normal driving in Missouri for its life. Should I flush the transmission and coolant again and if so, when? Everyone has different opinions it seems. Thank you!

[Tigerfan7777]

And should I replace power steering and brake fluds too?

[Ilya]

If they were all changed at 90k (should be able to confirm this with the dealer as they should have the records on their computer for your VIN) then you are probably okay with doing the transmission fluid. However, your car is high mileage so it may be better to just leave that.

Coolant, power steering and brake fluid I'd definitely do.

[Tigerfan7777]

the infiniti dealer changed transmission fluid and only charged me for 5 quarts of transmission fluid-its an 07 m35 base 2wd. Service Advisor states the transmission holds 10 quarts and 5 of those are in torque converter which they do not drain. does that sound right? here is service manual http://www.nicoclub.com/service-manual? ... M45-M35/at

[steve_c]

Service advisor is correct, although the actual displacement of fluid he quoted was approximate.
What he did was a transmission pan fluid change R&R as opposed to a complete transmission fluid change out.

Don't forget transmission fluid resides in the lines & transmission cooler assembly as well as residual fluid in the
valve body cavities, pump, etc. in addition to the pan & t/converter.

[Tigerfan7777]

thanks but i meant was that the proper/best procedure at this stage for my transmission? it has 142k and was flushed at 90. When i read the service manual in my last post it doesnt simply say drain half and refill. And my second question is why dont they drain all of it and refill? Much obliged

[steve_c]

Good question,....but,
A bit hard to answer because which is best depends upon the condition of the existing fluid and prior maintenance (fluid service) and condition of the transmission.
In my case, I had the original fluid in the car for 75+k miles. At that juncture, I knew the fluid was old & tired, so I did a complete flush, running 14 qts. of fluid through the system until the flow was a nice bright cherry red.
I now have 120k miles, and recently performed a 2x trans pan fluid change out (approximately 4 qts. per fluid change). I did the first pan exchange, drove the car a day or two, then did the procedure again.
At the 75k mark, I used Nissan-Matic S to replace the original OEM fill of Nissan-Matic J (now obsolete). At 120k, I used OEM Nissan-Matic S also, & all is well.

If I had your car, based on what you describe, I would probably start with a pan change-out first. Ask the tech to take a small sample of the old fluid in a clean seal-able container, and then ask him how it looks & smells. There is an excellent video on U-tube about how to do a quick analysis of your fluid:

https://youtu.be/o690DovjDAc

If you really want to dial in what is going on within your transmission, send the sample fluid off to Blackstone or equivalent to get an analysis.

Bottom line,..watch the video, then post back to discuss further!

[reefscape15]

I think the pan drop method is the way I'll go. No idea when transmission was ever flushed, 156k on car. Has a shift issue going into 3rd....figure I'll try this and see if it makes any difference

[Malbec 56 Beast]

I would only do drain and fill. I will never do a trans flush again. Dealer here in Utah doesn't even use factory fluid.

I only use Amsoil in all the powertrain systems.
Not impressed with the fluids that come from the factory either.

Really smoothed out my 04 Maxima and my 2010 G37xS.

My.02

Andy