Transmission & Differentials

[alii143]

I am willing to change the Transmission & Differential fluid for my Genny and I am honestly confused about the following and just dont want to mess up the car

1) correct me if I am wrong, do I need to drain and refill the Differential fluid multiple times or one time is enough. And what is the best fluid to use ? Amsoil ? Do I need to add Slip Lock or Amsoil alone would do the job.
- And if I will go with the factory fluid to i need to add Slip Lock too? Or any other additives ?

2) Regarding the Transmission Oil, again.. Amsoil will do the job? And if I will go with factory oil, do I need to add any extra additives?
- Regarding the drain and fill process, do I need to do it multiple times or just once. If its to be done multiple times, what's actually the process ...

For the Transmission Oil Change, Following the same exact steps of this video will keep things safe or there's something he's missing:

 

[blnewto]

We had chat on reddit.
First off, how many miles on your G70? I wouldn't worry about the transmission service until 60 to 70k miles, and when you do it do a 2 or 3x drain & fill w/ driving through the gears and putting a couple hundred miles between each drain & fill.

Some do a single drain & fill then do another 10k miles later, IMO it really doesn't matter too much but I think I'd like to get a majority of fresh ATF in the transmission sooner than later. @Volfy mentioned in another thread that Valvoline Maxlife ATF meets the Hyundai SP-IV-RR specs. I've used Maxlife in a couple vehicles, and it's worked well (A Toyota Tacoma and Infiniti G37). It's less than $30/gallon so makes the drain & fills much more affordable. Here's that Maxlife spec sheet/info

US_Val_MLMultiVehicle_ATF_EN.pdf - Docusign CLM

sharena21.springcm.com

If I were doing the drain & fill the first time I would probably want to remove the pan, this will drain more fluid and you'll be able to clean out the pan and the magnets.

When doing the rear differential (I have a RWD so I can't comment on the front if you have AWD) it's a very simple drain & refill. I just backed my car up on ramps and drained into a marked bucket, it drained out a bit less than 1.5 qts and I filled 1.5 qts back in. I used Royal Purple, has worked well!

Amazon.com

Post in thread 'Changing Rear Diff Fluid'

Nov 17, 2024

Just changed mine today (RWD 3.3 LSD) and was simple. I used a 6pt 15/16" socket on the drain & fill plugs, tried a 24mm 6pt and the 15/16 was a tighter fit, and since the drain plugs have a shallow head on them I prefer a tight fit there as wouldn't be hard to round them off. The fill plug wasn't very tight but the drain plug took a lot more effort to break free. The drain plug appears to have a thread locker on the threads so that could be why it took more effort to break it loose. I re-used the copper washers but will order new ones next time around, have seen a few DIY videos and were...

• blnewto

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[alii143]

The car is 40k now, and it is RWD. I am aware the Transmission fluid to be changed at 60k miles as per the owners manual. And what do you think about Amsoil ATF, would suit the SP-IV-RR Specs?

And thats what I was thinking, to perform full oil change and just drop the pan. But some genesis owners somehow wouldn't recommend that for some reason. Thinking about it logically, I dont think it will cause an issue if you will just drop the pan and perform full transmission oil change at once

 

[blnewto]

The car is 40k now, and it is RWD. I am aware the Transmission fluid to be changed at 60k miles as per the owners manual. And what do you think about Amsoil ATF, would suit the SP-IV-RR Specs?

And thats what I was thinking, to perform full oil change and just drop the pan. But some genesis owners somehow wouldn't recommend that for some reason. Thinking about it logically, I dont think it will cause an issue if you will just drop the pan and perform full transmission oil change at once

If you can drop the pan and clean it along with the magnets that should be in the pan that would be a plus. You should drain a bit more fluid that way. I'm pretty sure you have to buy a new pan that comes with a filter if you want a filter change. I haven't heard that you can just buy the filter, but could be wrong there.

 

[Volfy]

The car is 40k now, and it is RWD. I am aware the Transmission fluid to be changed at 60k miles as per the owners manual. And what do you think about Amsoil ATF, would suit the SP-IV-RR Specs?

Amsoil ATF is fine. So are a lot of other commercially available name-brand ATFs that list being compatible SP-IV-RR. New fluid is infinitely better than 60k old ATF.

And thats what I was thinking, to perform full oil change and just drop the pan. But some genesis owners somehow wouldn't recommend that for some reason. Thinking about it logically, I dont think it will cause an issue if you will just drop the pan and perform full transmission oil change at once

FWIW, there is really no such thing as "full" trans fluid change. See here: Serious Transmission Jerking/Knocking noise when accelerating