Transmission not engaging when it gets hot?

2006 TOYOTA COROLLA

150,000 MILES • 1.8L • 4 CYL • 4WD • AUTOMATIC

MARCMATROY123

MEMBER
1 POST

After a transmission overhaul we changed the oil pump, clutches, and some seals. We also rebuilt the primary variator, just the seal, we wrapped some cotton on the base where the seal sits as the air pressure test failed after rebuilding. The vehicle runs perfectly when cold but once the transmission gets hot no gear is engaging.

May 31, 2023 at 1:26 PM

JACOBANDNICKOLAS

✓ASE Certified Mechanic
110,194 POSTS

If you lose all gears, it sounds like you are losing line pressure. Have you been able to check that? Also, have you checked to make sure there aren't relevant diagnostic trouble codes related to the transmission?

I attached the directions below for testing line pressure. Let me know if this is something you are comfortable performing.

Take care,

joe

See pics below.

Images (Click to enlarge)

Professional Diagram for 2CarPros Members
Click here to log in and view diagram.

Jun 1, 2023 at 10:15 PM

STRAILER

✓ASE Certified Mechanic
54,837 POSTS

Are there any codes?

Here is a guide to help us:

https://www.2carpros.com/articles/why-does-your-automotive-transmission-not-engage-when-it-gets-hot-a

Also, it sounds like you may have a bad fluid pressure switch which I have included the location in case a code comes up for it.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Check out the images (below). Let us know what happens and please upload pictures or videos of the problem so we can see what's going on.

Image (Click to enlarge)

Professional Diagram for 2CarPros Members
Click here to log in and view diagram.

Jun 2, 2023 at 7:12 AM

Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.