I'm pretty sure that I need to change the trans and differential fluid. Is a trans flush a good idea? 84k miles on it. I've been told to avoid an engine flush because they're too aggressive and can stress seals etc. Wondering if this is the case with a trans too? Anyway, I'll need to take a look at it to keep my warranty active.

On a side note, I've also been told to stay away from Royal Purple engine oil, as this can stress gaskets, seals, etc.

 

I've already done hours of research on these issues as well. My general conclusions - anything that artificially pumps the fluids through the transmission or engine is usually not good. Regarding the tranny flush, the fluid is usually pumped through in reverse to its normal course, from my understanding, which can torment valves within the tranny and push debris into inopportune areas where the normal pressure and flow of the ATF would not not allow debris to deposit. Don't do a flush, do do a drain and fill.

I haven't done it to see for myself , but some folks will disconnect the ATF lines at the bottom of the radiator to get most of the ATF out. I just do the partial drain and fill of ATF from the ATF pan, which usually removes about 4 of the 11 qts, IIRC, every 30K miles or sometimes more.

As for engine oil, there are lots of G35 drivers who swear by the Royal Purple. I don't buy it - I just grab a 5qt jug of Mobile1 Synthetic Geriatric for the old lady. The price is right, and you know you're in a lot of good company in using it. Plus, I go about 7K miles between changes, no problem. Like most G35s, mine burns oil - 2 qts every 7K miles, usually.

 

Yea, I'll do the drain and fill on the trans and rear end. I just want to make sure I'm covering my maintenance and will keep the warranty company happy.

Have you heard anything about synthetic motor oil not being as good to gaskets as conventional?

 

Yeah, I've heard people come up with all sorts of crazy theories about traditional oil, synthetics, blends, and how to use them and not use them.

Typically, a car will come from the factory with DINO. It's best, from what I've been able to read, to leave the DINO in for a change or two, then switch to syn. Running DINO for a while allows the seals to seat more effectively.

From there on, you can do whatever you want.

 

Ok, thanks for the info Munkle.

I'm going to get the oil done over the weekend and was told to keep an eye on the color right after I change it to gauge if I have built up sludge in there. As you can see, I'm a newb to this and just thinking out loud. I guess if the color isn't too bad after the change and I don't need to constantly change the oil, then synthetic will work fine.

Thanks!

 

All false.


I personally run conventional oil because my engine burns a little. But quality oil is quality oil. As long as you aren't sticking Joe Blows recycled oil into the engine, you should be fine with any modern oil (of proper spec) sold these days.


As for transmission drain/fills, i try to do mine every 30K miles. I just replace 4 quarts of Matic-S. I'm at 130K, so i'm due for my 4th drain/fill.

It hasn't made a difference on the 2-3 shift at all really. I only get it in manual mode, and to be honest I never really use manual mode. I just need a clutch pedal or it doesn't feel right

 

There are certain RPM ranges in which you won't feel that thud when shifting between 2nd and 3rd. I've found that shifting is smooth between 3K and 4K while accelerating, then again just before the redline. Give it a shot and report back!

 

Hey thanks for the replies guys!

I'll have my oil changed and see what it's like the day after then. If it's already dark and I'll need to keep changing it, then I'll hold off on the synthetic, other wise I'll use it.

I've noticed that it's hit or miss for the 2nd to 3rd shift, but you're right, certain rpm ranges act differently. There's a merge up the street from me at a 4 way stop that is slightly uphill (It's Florida, so no crazy hills). If I go to manual mode to merge there, it always thuds from 2nd to 3rd. I don't know if this has more to do with the hill or that the car hasn't been running for that long before I get to that area.