DIY: Transmission Oil Change

LinPark

Ordered everything I need from Z1 recently and am planning to put it all to use this weekend. I had planned on doing this a few months ago and stopped in the Nissan dealership to pick up the gaskets and of course all they had was 1 in stock - I bought it anyway. I also got 4 from Z1 - here's a pic of both of them together:



The Nissan dealer part looks more like what is on the drain plugs in pics that have been posted in this thread and the DIY Differential thread. Should I seek out 3 more of the OEM gaskets or is it safe to simply remove the old one and go with the copper style Z1 washers?

Jsolo

Edit, looks like z1 is supplying copper washers in place of the aluminum ones. I've done my trans fluid twice now. Reused the washers both times.

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ShockWave

Do you really need to replace the transmission fluid/oil every 20,000 miles or 24 months?

JARblue

Those copper style washers look very similar to the ones for the power steering. They're probably fine, but I would go ahead and try to find the OEM gaskets/washers. But that's just me ... YMMV

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TreeSemdyZee

Clean fluid never hurts.
I NEVER go by factory specs on fluids. It's not that expensive in the long run and it could give you a crap load more miles. If that's what you're wanting.

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JARblue

I never understood why people question using shorter interval period for fluids. If the $$$ is an issue, just learn to DIY (or get another car and stop living above your means ). By doing the work yourself, you can change fluids twice as often with higher quality expensive fluids and still save a decent amount of money over using the dealer.

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dkmura

Regarding the mileage/time factor, I had the MT85 in my T3 SCCA racecar tested by Blackstone this spring. I'd left it in for three years and wanted to see how it tested. Plenty of life left (low TAN), but iron wear was a trace higher than their universal averages. After talking with them, they suggested pulling another sample in 2018 and comparing.

Keep in mind, this tranny gets used extremely hard during race season, but rarely sees much mileage outside of that. Probably 1,400 of the hardest miles on any Z tranny out there.

barncobob

don't know what testing cost$ but might be cheaper to just change the fluid..

dkmura

Testing in bulk is about $28, but cost is not the primary reason to do it. It provides a snapshot of the overall health of a component, like an engine or gearbox. It also let's you know whether a particular product is working well for that application.

In my case, my Z gearbox is in pretty good shape, considering the heaps of abuse and heat it gets subjected to in racing. MT85 is doing a good job preserving the primary parts like syncros, main shafts and other seals that would otherwise need a teardown to determine.

And yes, it's still cheaper to do a UOA than "just change the fluid".

JARblue

Interesting

Can you post a print of the analysis results?

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LinPark

I don't have one for the transmission fluid because I haven't changed it out but here is one from an oil change quite some time back. Been doing these with every oil change since I got the car so I have an idea of how things are going and fully intend to do it with the first batch of transmission fluid.

LinPark

Finally got around to doing this today and of course I forgot to take a sample.

Not as easy as an oil change and a bit messier but overall a nice little DIY project so you can spend time in the garage with your other lady.

I will mention that the original washers were identical to the silver ones I posted awhile back and to be honest they looked completely re-usable. I went ahead and used the new copper ones that Z1 sent with the order.

Up next will be the differential.

JARblue

FWIW, I once compared a used trans/diff gasket/washer to a new one using a digital caliper and the difference was barely enough to confirm that it is a "crush" washer of sorts (though it is nothing like the oil pan drain plug copper crush washer). Not enough to worry about reusing if you don't have new ones. I'm certain I have reused one or more at least once when I mixed up the new and the used washers during a fluid change.

But considering the cost of a new washer is so minimal, I just prefer to know that its new every time. I keep a handy stock of them now and have plenty to share with local forum members if they need them as well

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jliu

2014 with 11k miles. Did the oil/filter change today and decided to change out the tranny fluid with Redline MT85, and the rear differential fluid with Redline 75w90 gear oil.

Fairly uneventful. The tranny oil was super clean and it took a bit more than 3 quarts before fluid started to spill out of the fill hole. The differential fluid was black and had some slush debris around the magnetic drain plug.

Initial drive appeared the shifting was a bit smoother, but not much.

SINISTER

I just did the exact changes myself today...super easy but a bit time consuming getting the car level etc. I found also that it took just a bit over 3 quarts for the trans. before fluid started to spill out but the service manual clearly shows 3 quarts. So it must have been at the perfect level before I did a couple of extra pumps of fluid....rather be a just a dab over then under...