Manual transmission oil: GL4 or GL5?

[Xion]

The owner manual recommend GL4 oil but the auto part told me his GL5 synthetic oil also complies with GL4 oil. I need an expert to tell me if I can use GL5 oil?? some say it's a myth that GL5 oil is no good for GL4 trannies. see linkGL4 vs GL5 gear oil, the plot thickens. - Benzworld.org - Mercedes-Benz Discussion Forum

[MTD]

From the Amsoil website, which is what I use.


Engine Oil
*****Grade 1......SM
Maximum Performance SAE 5W-20 Signature Series 100% Synthetic Motor Oil (ALMQT)
Performance Plus XL 5W-20 Synthetic Motor Oil (XLMQT)
Performance Synthetic 5W20 OE Motor Oil (OEMQT) *****Above 0 F......10W-30
*****All TEMPS......5W-20, 5W-30*[1]
Manual Transmission,M6CF3 (6-SPD)......GL-4
*****All TEMPS......75W-85
*********Synthetic Manual Transmission and Transaxle Gear Lube (75W-90) API GL-4 (MTGQT)
Automatic Transmission,A6GF1......SLF*[2]
*********Low Viscosity Synthetic ATF (ATLQT)
Fluids
*****Clutch Fluid......HB
*********AMSOIL Brake Fluid DOT-3 (BF3SN)
*****Brake Fluid......HB
*********AMSOIL Brake Fluid DOT-3 (BF3SN)
*****Clutch Fluid......
[1] SAE 5W-20 is preferred.
[2] Hyundai Genuine ATF SP-IV or equivalent.
specification approved by Hyundai Motors Corp.
*FILTERS:
Oil Filter Absolute Efficiency Oil Filter (EA15K20) [1]
Oil Filter WIX 51334 Oil Filter
[1] Replaces the Ea15k46, which will still work for this vehicle
*NGK PLUGS AND WIRESETS:
No Recommendations
*WIPER BLADES:
No Recommendations
*CHASSIS LUBRICATION:
******0 Fittings, 0 Plugs
*CAPACITIES:
Engine, with filter..........4.2 quarts*[1]
Cooling System, AT Initial Fill..........6.2 quarts
AMSOIL Antifreeze and Engine Coolant
Cooling System, MT Initial Fill..........6.3 quarts
AMSOIL Antifreeze and Engine Coolant
Automatic Transmission, A6GF1 Initial Fill..........Not Specified
Automatic Transmission, Total Fill
***6 speed A6GF1..........7.7 quarts
Manual Transmission, M6CF3 (6-SPD)..........4 pints

[sbr711]

Hyundai manual trans class says NO GL5 in the GL4 specced gearboxes.. GL5 will ruin the brass synchro rings

Couple choice for GL4, Penzoil had a sythetic GL4 oil, REDLINE offer 2 flavor of GL4, and Hyundai stuff sold in qts at the local Hyundai and Kia dealer part counter.

BTW,, did this auto store fella go to Hyundai school to know anything about your car ?

[stephen9666]

The genuine Hyundai fluid isn't cheap, but it's a full synthetic fluid made by SK Lubricants (a well-regarded Korean oil company) and it works well in my Sonata. I think I paid $15/qt at my local dealer. It took two quarts.

I've become a convert to only using genuine dealer transmission fluid in my cars with manual transmissions. Some are very sensitive and won't shift properly with some aftermarket fluids, even fluids that claim to meet the required specs.

I had problems with my Nissan Frontier shifting poorly with Amsoil and Royal Purple, which are both expensive boutique oils. I went back to the Nissan fluid and it's been fine.

I know the dealer fluid isn't cheap, but if you put something in that doesn't work well, you'll have to do the job over again and you'll probably lose all the savings from going with an aftermarket fluid.

[Xion]

Are you saying the dealer's oil is full synthetic? it's the only reason I wanna change it because some reported smother shifts, also one member said there was metal particle in his oil when he changed it so now I feel like I must change mine.

[stephen9666]

The fluid I bought said it was synthetic. I didn't keep the bottles, or I'd post a pic.

Go to the dealer and take a look at it. They should have it in stock.

[Xion]

Originally Posted by stephen9666

The fluid I bought said it was synthetic. I didn't keep the bottles, or I'd post a pic.

Go to the dealer and take a look at it. They should have it in stock.

OK thanks a lot, was it hard to change the oil?

[swduncan]

Originally Posted by Xion

OK thanks a lot, was it hard to change the oil?

I've looked at the service manual, and it seems straight forward, drain plug on the bottom and a side fill until it starts to drool out a bit. Re-install the fill plug.

[apu]

GL5 oils might work in some GL4 spec trannies but they are not always backward compatible, as mentioned previously they may be have adverse effects on soft brass parts if present. Stick with GL4 as Hyundai is very specific about this. If you find some redline stay with the recommended MT85(75W80 GL4) not the more popular MT90(it's too thick especially when cold). They also carry MTL but it might be a little too thin. Otherwise check the OEM oil, if it's truely synthetic at $15/liter it's the same price I paid for my redline here in Winnipeg.

Changing the oil is easy, only tricky part is puting new oil in, you will need either a funnel with a long tube attached and a second pair of hands if it's from the top of engine or a cheap $10 oil transfer pump from the bottom(way easier). If you were closer I would offer to help you with it.

[Xion]

Originally Posted by swduncan

I've looked at the service manual, and it seems straight forward, drain plug on the bottom and a side fill until it starts to drool out a bit. Re-install the fill plug.

My last question: why did you change the oil in a 2012 car?