Just wondering how often I should replace the Transmission and Differential Fluid ?

 

Well according to the FSM every 60 000 miles. I just replaced both mine after 50 000 km's and actually put in good quality oil and the shifting feels a hundred times better than before.

I'm running Red Line MT90 for tranny (2.5 litres) and Redline 75-90W (1.3 litres) for my diff.

 

is there any kind of time limit (such as the 3 month rule for motor oil).
i ask just because our cars may have 15 year old fluid in them but have yet to reach such a milage.

 

Looks kinda tricky to get under there and pour oil into it... Did you have to lift the car?

 

They make syringes to injecto the tranny fluid.

Also, unless you're a REALLY small person, you'll need to lift the car to reach...

 

Gear oil life depends on how hard the car is driven, how hot the tranny gets, and whether any moisture has condensed inside.

Changing any less than 30k is kinda silly unless you're rebuilding the tranny. Change it by 60k though since old / dirty oil is not good.

You'll need to lift the car to change the oil. I run a long tube from the fill port into the engine bay and fill through there.

Dave

 

My trans feels overly notchy and I've heard that the Redline MTF will help.

 

The concensus seems to be that Neo is the best:

https://www.rx7club.com/showthread.p...ight=neo+75W90

 

I'm no expert myself when it comes to fixing cars but I actually manage to change both the tranny and diff oil myself which was rather simple. Once you get the transmission cover off it looks a lot less threatening as you can actually see the sump plugs.

After you manage to jack up the car and drain everything, I simply used some garden hose and cut about 1 metre of it. Surprisingly it fit perfectly in the filler plug and I just ran it from the engine bay down the back of the engine and then down tranny tunnel.

Other end I used a funnel and filled the whole thing up in about 5 minutes. Just make sure to wash the hose as the last thing you want when shifting is bits of pebble or what not in there.

Fill about 2.6 litres then take the hose out and let the oil overflow. Once it stops then your done. The diff was alot easier as the plugs are above each other.

Trust me its not that hard.

 

I'm sold, Neo it is.....
thanks

 

make sure you use the correct fill plug on the trans, the wrong one will cause you to overfill. Also a tip: take out the fill plugs (trans, diff) first - this way if for some reason you cannot get them out you would not have drained out the existing fluids yet.

 

i personally don't think it makes a lot of difference between the premium synthetics. But I do believe it helps to use a GL-4 in the tranny and a GL-5 in the diff. For the tranny the best options are Amsoil MTG (GL-4) and Redline MT-90.

Neo covers both applications but I don't think it's exactly the best for both. To make a long story short, what's good for the hypoid gear of the diff is not good for the synchros in the tranny. So in the future I'll be using different fluids in each.

Dave

 

Don't forget that on the transmission there are two drain plugs, one fill.

 

And remember to always remove the fill plug first. That way you are certain that you can refill it once you drain it.

The FAQ thread has good links to How To procedures for this so check that out.