scturbo28

hello community i have a r154 transmission and was wondering were the drain plug to this type of tranny is , i would like to change the transmission fluid but don't know were the plug is , also were do i refill it again once i drain all the fluid thank you. whats the best transmission fluid i can run in this type of tranny.

Blizzy

iTrader: (-1)

The drain plug is along the body of the main body of the transmission (neither the bell housing that attaches to the body nor the tail housing into which the shift rod inserts). It is a large bolt (24mm or 15/16", if memory serves me).

Being at the bottom of the transmission, the drain plug allows the gear oil to flow out of the transmission by way of gravity, assuming the car is level while elevated.

Note the location of Drain Plug next to 21:


The filler plug is in the near the middle of the tail housing of the transmission (the part into which the shift rod inserts). It is also a large bolt (same size as the drain plug).

Being near the middle of the transmission, the filler plug allows any amount of gear oil that would rise to a level above the filler plug to pour out by way of gravity, allowing just the right amount of gear oil in the transmission, assuming the car is level while elevated.

Note the location of Filler Plug:


This depends on your application.

In 95% of cases, a synthetic 75w90 is your best bet. Royal Purple makes a product called MaxGear in a 75w90. Redline makes an MTL-90. Mobil 1 and Amsoil also make a 75w90. Royal Purple is generally viewed to be the Holy Grail of gear oil. Given the questions that you have asked in this thread without any qualification, it is even more likely that you will fall into this category.

If you do not drive your car hard (granny shift into gear, almost never downshift, rarely let the engine spin to over 3k) and you would prefer to get 2-3% better fuel economy, then you could go with a slightly underweight fluid to reduce hydrodynamic drag in the transmission. Redline's MTL (not MTL-90) would be a fine option. I run this stuff in my Tercel, and it boosted economy about a full mpg, on average, but I am never pushing the car. With an underweight gear oil, pushing the car would heat up the transmission fluid to a temperature at which the coefficient of friction of the fluid would become lower than the transmission would prefer and you risk premature failure.

If you do not drive the car light (shifting hard and quick in a racing application, downshifting often, and rarely keeping the engine under 2k rpm) and you would prefer added heat tolerance, then you could go with a slightly overweight fluid to prevent thermal breakdown. A 75w140 would be the way to go here. I run Royal Purple 75w140 in the R154 on my SC400 since when I am found driving my Lexus, I am very often driving it hard and will be taking it to the track in the future. With the slightly overweight gear oil, the transmission prefers to be pushed and feels the best when it is hot. The smoothness of cold start is sacrificed as a result, but I can be assured that the coefficient of friction of the fluid will never become lower than the transmission would prefer no matter how hot the transmission becomes. However, excessive cold operation would maintain the coefficient of friction too high for too long, risking premature failure.

Like I said: in almost all cases, the 75w90 is the way to go. Toyota engineers designed the transmission to work with 75w90, so if you are driving the car the way it was designed, then don't overthink the Toyota engineers and stick with the 75w90. However, if you are driving the car in a way it was not intended -either too light or too hard- then you may be more well served with a slightly overweight or underweight gear oil to better suit your unique application.

In any case, you will need 4 quarts of oil to fill the transmission to its 3.2 quart capacity.