Manual trans fluid for 2010 kia forte 6sp

[aquariuscsm]

2010 Kia Forte owner manual
Manual transaxle fluid:
- 2.0 Engine 1.9l (2.0 US qt.) API GL-4 (SAE 75W-85, fill for life)
- 2.4 Engine 1.8l (1.9 US qt.) (ZIC GF TOP or HD GEAR OIL XLS)

In my manual cars I run RedLine MT90, and shifting is better than any other fluid I tried, such as Honda MTF, Pennzoil Synchromesh, etc. Just make sure to stay with GL4, as GL5 gear oils will eat up all the brass components inside the transmission. I also heard great things about RedLine MTL (lower viscosity than MT90) and Royal Purple Synchromax (with the magic Synerlec unicorn juice). I do plan to try both eventually.

MT90 also never seems to deteriorate over time (shifting quality stays good as new). Love that stuff!!

 

[ram_man]

So valvoline synchromesh actually lists that it meets the vw audi spec G052171a2 which is a 75w80. The factory fill in the m6gf2 transmission that is in the forte calls for a 75w85. However some on the forums felt like the factory fluid was to thick for the transmission and wasn't the best option for optimum shift quality. Obviously there is a debate to be had there. But wouldn't the valvoline synchromesh be thinner but not drastically so?

 

[Snowflake White]

So valvoline synchromesh actually lists that it meets the vw audi spec G052171a2 which is a 75w80. The factory fill in the m6gf2 transmission that is in the forte calls for a 75w85. However some on the forums felt like the factory fluid was to thick for the transmission and wasn't the best option for optimum shift quality. Obviously there is a debate to be had there. But wouldn't the valvoline synchromesh be thinner but not drastically so?

It may be that the slightly higher viscosity 75w85 is better in warmer or hot climates, I bet the 75w80 products are just fine in temperate climates or cold climates but might accelerate wear slightly in tropical or hot climate conditions. The most critical aspect is to make sure you use the correct
GL spec, and for this model it is GL-4.

 

[jayjr1105]

Used Redline MTL 75w80 GL4 in my Mazda 6 speed. Was a fairly easy job and it only used 1.8qts. Only drained 1.5qts of factory fluid too so I'm glad I did it. Lifetime my ass.