Got a newbie question for you all and thanks in advance.

I have a 2003 G35 sedan automatic that has about 33K on it. I'm 2nd owner and have had since about 20K. I have beat on it a little bit, but not super hard. It appears it's about time for the 30K servicing & I wanted some advice for the trans fluid. Should I have the thing flushed or have the pan dropped and the filter serviced instead? A mechanic I have dealt with a little (older gent, lots of experience, but may not be up to snuff on the latest technical trends) says I should drop the pan & clean the filter to remove any gunk thats there, even though it will not replace all the trans fluid. This will avoid trans fluid shock, which is were the tranny freaks out since all the fluid is new. Or do you recommend a standard trans flush?

I'm not super up on G35 stuff (been too busy) so I reaching out to anyone who can guide me in the right direction. Thanks for all the help.

 

Hello Miamimart. Based on my 24 years managing an auto center and seeing the results on almost a daily basis of exactly what you mention above, I recommend performing both procedures. A transmission doesn't mind fresh, clean fluid and will perform better because of it. Neglecting the transmission fluid will eventually lead to a very costly transmission rebuild, usually to the tune of $1,500 - $2,000 in cost, sometimes even more. Automatic transmissions these days are just way too expensive to neglect. If you want a longer lasting transmission, along with improved shifting, lower transmission temperatures, a boost in fuel economy and performance, use a high performing synthetic automatic transmission fluid.

Good luck with it.

Steve - Hi-Tech Oil Co.

 

Never heard of fluid shock before. Sounds like an urban myth to me. Changing as much of the fluid to fresh just makes sense. Do the flush.

 

Regular tranny changes, say every 25K at most should do the trick.
Maybe at 60K+ you want to do more like dropping the pan. Power flushing carries some risk unless the operator is well versed in the procedure.
The old way of doing it though the coolant lines with the engine idling are safer if slower and not as 'cool'.
And if you do regular changes no reason for chemical cleaning which adds even more risk.
Use the factory fluid as recommended and you will never have an issue should there be a premature failure. My two inflated cents.

 

With only 33k miles on it you should be fine with just to drain the oil through the plug and refill. I rebuild transmissions for a living and 33k is not much. Fluid shock is possible/ when there is too much break down material in the tranny fluid, it will begin to conduct electricity from the solenoids eventually shorting one of the solenoids out.

 

So, fluid shock is from the stuff floating around in the old fluid, correct? That should mean changing as much as you can to fresh fluid would be better rather than mixing with the old fluid.

 

Seems like an non-issue as long as you change out at regular intervals.

If that means totally flushing instead of draining, then do what's comfortable for you and your wallet.
So far have never seen this pop up as technical issue for our cars.

 

I would drop the pan first. The reason being the most wear occurs early in the transmission's life. I would drop it to clean the magnets in the pan and also to wipe down the screen that acts as a filter. The only time that I have heard of "fluid shock" was in vehicles where the original fluid was in too long, say 80k miles or more then it gets a flush and a slipping condition developed in the transmission.

 

That's what I meant by fluid shock, where the trans fluid has been in there for extended mileage and when all the fluid is changed, the tranny freaks out..so to speak. Any more opinions are welcome.....thanks

 

The service interval for the 5AT is at 60K miles. You've got a long time before a fluid change.