Howard Sterndrive
Rear Admiral
- Joined
- Nov 5, 2008
- Messages
- 4,603
My wife's Kia requires 75W90 GL4 in the 5 speed transaxle. I was pretty sure GL5 was not a good substitute, but did some googling to make sure I was thinking of the right thing. I was.
GL5 has additives that wear out the synchronizers and that's why the car's manual is calling for GL4 specifically. There are dozens of threads and articles warning of premature synchro wear from GL5 - as additives react with the bronze.
So, after trying to teach this concept to the mouth-breathing clerks at each the 4 parts stores in town (who only have GL5 or multi-spec oils which are not going in my trans) and reliving a scene from idiocracy at each, I headed to the dealer. I figured I can shell out the big bucks and maybe I'll just get them to change it.
So, I explain what I want to the service advisor. And (in a condescending tone) she barks "it's just gear oil, you can use any gear oil"
She then proceeded to tell me that GL5 is fine and I can buy it anywhere and that's all they have been using for 9 years.
Holy heck. That's a scary attitude on a lot of levels. I called Kia customer service to see if maybe I was over reacting. and they confirmed "GL4 only".
After work, I head to Hyundai (as our car has a Hyundai driveline). Although the staff there are super friendly... they bring me a jug of ATF first, then after I explain the GL4 thing, they make a call to the tech line where they are told "it takes 75W90, not GL4"... wow...they don't know the difference between a viscosity and a spec... and this is their profession?
Then they bring me GL5. :facepalm:
ok... Ford dealer next - they carry no manual transmission fluids, only ATF... wha? well, at least they aren't harming vehicles.
I went home and ordered some GL4 75W90 from Amsoil. It arrived the next day!! awesome. I changed it myself in about an hour
Funny thing too, while looking for GL4 spec oils, it appears some lower unit lubes are GL4. The old Pennzoil 75W90 synthetic (looks identical and smells identical to the Amsoil stuff btw) and Sierra's lower unit stuff is also spec'd GL4.
I suspect others are too, especially if going in cone clutch drives, but they don't tend to put on-the-road specs on most, so I wasn't about to put the Mercruiser stuff in as tempting as that was as much as I have here.
GL5 has additives that wear out the synchronizers and that's why the car's manual is calling for GL4 specifically. There are dozens of threads and articles warning of premature synchro wear from GL5 - as additives react with the bronze.
So, after trying to teach this concept to the mouth-breathing clerks at each the 4 parts stores in town (who only have GL5 or multi-spec oils which are not going in my trans) and reliving a scene from idiocracy at each, I headed to the dealer. I figured I can shell out the big bucks and maybe I'll just get them to change it.
So, I explain what I want to the service advisor. And (in a condescending tone) she barks "it's just gear oil, you can use any gear oil"
She then proceeded to tell me that GL5 is fine and I can buy it anywhere and that's all they have been using for 9 years.
Holy heck. That's a scary attitude on a lot of levels. I called Kia customer service to see if maybe I was over reacting. and they confirmed "GL4 only".
After work, I head to Hyundai (as our car has a Hyundai driveline). Although the staff there are super friendly... they bring me a jug of ATF first, then after I explain the GL4 thing, they make a call to the tech line where they are told "it takes 75W90, not GL4"... wow...they don't know the difference between a viscosity and a spec... and this is their profession?
Then they bring me GL5. :facepalm:
ok... Ford dealer next - they carry no manual transmission fluids, only ATF... wha? well, at least they aren't harming vehicles.
I went home and ordered some GL4 75W90 from Amsoil. It arrived the next day!! awesome. I changed it myself in about an hour
Funny thing too, while looking for GL4 spec oils, it appears some lower unit lubes are GL4. The old Pennzoil 75W90 synthetic (looks identical and smells identical to the Amsoil stuff btw) and Sierra's lower unit stuff is also spec'd GL4.
I suspect others are too, especially if going in cone clutch drives, but they don't tend to put on-the-road specs on most, so I wasn't about to put the Mercruiser stuff in as tempting as that was as much as I have here.
