1992 Mitsubishi Diamante Hard down shift into first gear

1992 MITSUBISHI DIAMANTE
114,000 MILES • 6 CYL • 2WD • AUTOMATIC
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PRMORGANJ
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  • 5 POSTS
Took car in to AAMCO for a rebuild since hard shifting into OD and very hard down shift to first. They did the rebuild and then found that the TCU was bad and not talking to the main computer. So after 2 weeks in the shop they finally found a rebuild TCU and told me all was fixed.

After driving the car it upshifts fine but has a fairly hard (not as bad as before) downshift to first.

I told them and they want me to bring it back in. Fair enough, but do you have any ideas what could cause this?

Paul
Feb 1, 2009 at 2:31 PM
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KHLOW2008
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  • 41,814 POSTS
Hi Paul,

Thank you for the donation.

Harsh shifting are usually caused by inconsistent solenoid operations and most probably the rebuild people would replace the solenoids for you to rectify the problem.

Apart from the solenoids, it sometimes is caused by the brake band and readjustment is necessary.

Worse case scenario is a leaking line pressue caused by worn bushings or mainshaft bearing/sealing ring seats and that would require stripping the trans all over again.

A loose sensor connection or faulty sensor would also cause the problem and the rebuild people would have to do a diagnostic to verify this.
Feb 2, 2009 at 9:31 AM