1994 MITSUBISHI ECLIPSE AUTO TRANSMISSION INTERNAL PRESSURE

  • Tiny
  • kenintn
  • 1994 Mitsubishi Eclipse

Transmission problem
1994 Mitsubishi Eclipse 4 cyl Front Wheel Drive Automatic 162000 miles

My '94 eclipse keeps blowing the auto transmission dipstick out.

History: Transmission (TM) was rebuilt 12,000 miles ago, new radiator. Bad rebuild, transmission failed @ 4,300 miles, they had to redo. The shop then cut the TM cooling lines loose from new radiator and jurry rigged a 6" x12" heat exchanger to the radiator. Ever since rebuild I find dip stick blown out, fluid spraying everywhere. This tells be internal pressure is building up.

On top of the TM is a tube that I believe is the vent pipe (rubber cap over flaired tube) but it apparently is completely clogged up. Put drops of alchol in tube, just sat there, level did not fall.

Is there an orfice or something? What are my options for resolving this problem.

Thanks,
Ken

Saturday, April 17th, 2010 AT 2:24 PM

5 Answers

  • Tiny
  • KHLow2008
  • Expert
  • 41,976 posts

Hi Ken,

There is a breather plug at top of transmission and if ti is clogged, it would cause pressurte to build up. You need to clear the clogging. With dipstick removed, try some compressed air.

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Wednesday, April 21st, 2010 AT 10:32 AM
  • Tiny
  • kenintn
  • Member

Thanks for your reply.
I've tried blowing air through the vent tube, no luck. Tried carb cleaner in it thinking it would break up any type clog, no luck.

I'd like to know if this tube is supposed to be just a straight through tube vent or has a check valve or an orfice. I can't understand why it would be clogged unless the rebuild shop damaged the tube (bent it over) internally when they had it apart.

Anyone know where I can get a PDF file that would show the internals of the 1994 Mitsi. Eclipse GS 2.0 non turbo automatic transmission?

Thanks again,
Ken

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Thursday, April 22nd, 2010 AT 5:37 AM
  • Tiny
  • KHLow2008
  • Expert
  • 41,976 posts

Sorry I am not able to get any diagrams for you as our database does not have it.

The vent is straight through but not down in a straight line. It more or less has some chambers, sort of maze like.

When compressed air is blown through the vent, does any come out of the dipstick?
What type of plug is used? It is a special type that can breathe when plugged over the vent.

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Thursday, April 22nd, 2010 AT 9:32 AM
  • Tiny
  • kenintn
  • Member

The " plug" I noted is actually a rubber cap that fits loose over a 1/4" X 3" tube flaired on the end, protruding from the top of the transmission.

I tried blowing air through the tube but nothing comes out the dip stick or either of the TM cooling line tubes. Carb Cleaner just stood in the tube. This is why I was wondering if there was a reverse check or something to prevent dust from being sucked into the TM.

Again, thanks for the reply.

Ken

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Friday, April 23rd, 2010 AT 5:35 AM
  • Tiny
  • KHLow2008
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  • 41,976 posts

Guess the breather was accidentally sealed during the rebuilding process. You should get back to the persn who did it to get it checked/rectified.

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Friday, April 23rd, 2010 AT 8:15 AM

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