Poping on 5th

[kkyin]

I think this maybe a common problem
I can't stay in 5th gear, and shifting into reverse is quite hard as well.

Everytime I shift to fifth, it will pop out of it if I step on the gas.
Is that a easy problem to fix? or better leave it to the professionals?

[PATDIESEL]

You're low on trans fluid. Fill it and the popping out of fifth will go away and you should have alot ewasier time with reverse too. Do a search if you need to know how to fill it. It is simple. 2.8 quarts of synthetic 75w90 (drain the old first).

[kkyin]

oh, that's doable.
how does low fluid affect only the fifth?

One mechanic said it could be the syncho, I was worrying.

[slowmx3]

That doesn't nessisarily mean you are low on fluid. If you check the fluid and it is at the right level, its either an input bearing or output bearing, because when one of those bearing is bad, it usually affects the direct drive gear. Correct me if i'm wrong but i don't think the mx-3 tranny is an overdrive trans.

[PATDIESEL]

It isn't an overdrive trans. That is why 5th is so low. However, most of the time it is low on gear oil if it pops out of 5th gear. I know it sounds wierd being only 5th, but it is true. Check that first.

[kiwi_MX3]

5th gear is located outside the case in the area covered by the
steel cover so can be accesed with out removing the box.

All the shift indent balls can be accessed from the outside of the
case as well..

The GM25R is a two shaft gearbox with the reverse idler on its
own lay shaft check out this web page for pic's of a "H" box
which is identical in case setup and gear train layout.

http://www.mx6.com/forums/showthread.php?t=125108

Matt

[kkyin]

Beside the 5th gear problem.
Is the shifter supposed to move a bit toward neutral when gas is applied?

It happens in all gears. Whenever I step on the gas, the shifter jerk a bit toward to neutral position. And when my foot is off the gas, it goes back to its "slot". The movement isn't much, I can feel it when I put my hand on the shifter.

[Grants]

Yes thats ok, the box is under "load" when you put your foot down.

[MazdaMiester]

Low fluid may or may not cause this issue. Usually what causes this problem is people driving with their hand on the shift knob, its not an arm rest... what that does it try to make the transmission shift further into 5th than it needs to, and wears out the shift fork, its just cast aluminum and if you pull it i bet you'll see on the inside of the arc of the fork a shiney wear line, as well as the fingers being worn down. If the problem has been around for a long time its very possible to wear 5th gear unevenly, because it wont run all the way in 5th, which can cause damage to 5th gear. Due to the amount of metal that's been removed for the fork and or the gears, that all pools up at the end of the shift rods and makes it a challenge to get the car into those gears...the rods go through both case halfs and sometimes metal will get trapped between the rods and the end case. Pull your 5th gear pan and see how much metal is in there. if you find alot of metal youll need an impact and a 1in and a 1 and 1/4in socket(im pretty sure these are the sizes for the nuts on the shafts). Pull the gear assemblies out together, not piece by peice, use a zip tie to hold them together. You'll have to source a new fork, or a used one... alot of forks from other G5m transmissions will work. Hope this helps!
-Eric