# Automatic Trans problems... help please!?!?



## indyantihero (Mar 13, 2007)

i have an 87 300ZX turbo, it has 125,000 miles on it and the tranny is shifting pretty late and hard, it also seems to slip into gear occasionally... the tranny fluid is over full, could this cause these symptoms? also would a new filter and a flush help? or should i just swap the tranny with the spare i have and hope for the best?


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## mwolvin (May 21, 2004)

My first rule (and only) of tranny diagnosis is when in doubt, flush the thing. I've seen 4 or 5 different cars with tranny issues and all of them were resolved with a tranny fluid change and filter change. 

Helpful note-- most transmission fluid changes only replace about half the fluid in the transmission, so you may have several hundred miles of driving to do before the full benefit is realized.


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## Zen31ZR (Mar 24, 2004)

Over-full, the trans fluid would be frothing up and possibly overheating which would cause some of these problems. Does it shift differently when cold? If the shifting is the same no matter what, I'd be looking at the transmission computer. It could also be the actuators inside the transmission itself. Make sure the correct fluid is being used as well. As far as fluid changes, many shops can change the entire amount of fluid using a machine which circulates the new fluid through the transmission through pressure. This technology has been around since the early 90s.


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## mwolvin (May 21, 2004)

Sorry-- I should have clarified. I meant at home transmission fluid changes.


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## 0341TODD (Nov 15, 2003)

mwolvin said:


> My first rule (and only) of tranny diagnosis is when in doubt, flush the thing. I've seen 4 or 5 different cars with tranny issues and all of them were resolved with a tranny fluid change and filter change.
> 
> Helpful note-- most transmission fluid changes only replace about half the fluid in the transmission, so you may have several hundred miles of driving to do before the full benefit is realized.



X2 You should definetly change the fluid before you assume anything. I recently go rid of an avenger that didnt move.......the fluid was black, I changed it---fixed the problem and sold it.

If you take it anywhere to be checked out in case you have dificulties doing it yourself or cant, make sure to get a couple of opinions from different shop. With transmission problems it is easy to get sold into big talk about rebuilds etc etc.

Im assuming that you know to check the fluid level when the car is warmed up and can tell if it is burnt or not.
An easy way to flush the transmission and get the most fluid out is to disconnect the transmission cooler line to the radiator and run it until it starts to slow. Turn the car off and drop the pan. If you have funny chunks in the fluid then your clutches are starting to go.

I put my automatic through a lot of stress and actually dropped my valve body, ported it and started running hydraulic fluid. My transmission has 187K on it, I sometimes wish it would go so I can put my 5 speed in, but I really am curious how much of a beating it will take. I have a buddy on another forum that is running 11's with his 280zx with a stock rebuild and hydraulic fluid.


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