hotrodjohn71

I like to ask advice before any job and appreciate your help.
I have a 2006 Mustang GT. Have been having a problem for a while with a hesitation in shifting between 2nd and 3rd. The hesitation is about half a second where the rpm blips up a bit, and happens usually during the first half hour of driving the car after it has been cold. Through my research I have determined that this problem is being caused by the solenoid pack. Upon further investigation, I found that the new solenoid packs are an improvement over the stock ones. Can you give me any technical advice before I purchase and change out the solenoid pack? Thank you.

Derf00

Before anything else, I would check your fluid level. These transmissions are fickle when the fluid is low. Tranny fluid expands as it heats up so if you are on the low side of what is considered full, that could explain the issue that only seems to come up when cold. A Fluid level check does not require a transmission pan drop.

Other possibilities:

You need to flush and replace all of your trans fluid. Over time it does wear out and the whole "Lifetime" fluid fill is just BS. Typically you should be doing at least a drain and refill every 30-40K of what's in the pan. Ideally,a complete fluid replacement is advised but difficult to do for most DIYers so you have to take it to a shop.

There is a thermal valve in the valve body (basically a thermostat for tranny fluid) that remains closed when the fluid is cold. It is advised to defeat this feature by sticking the valve open or installing an aftermarket thermal valve from a shift kit so as not to restrict fluid while the trans is warming up. Restricted fluid flow can/will burn up the transmission.

hotrodjohn71

Thanks for your reply. I change the fluid every 30000 and changed it about 20000 ago. I don't think there's a problem with the level because I fill the fluid with the motor running until it comes out of the fill hole tube on the pan (the only fill hole).
Is that thermal valve readily accessible access term removing the pan?

Derf00

Good on both.

In order to access the thermal valve, the pan, solenoid pack (including reverse servo) and valve body have to be dropped. This picture shows the one minor change that has to be made to the OEM valve to stick it open.


It's a lot of work and about 8 quarts of fluid for something that may or may not work. At least at that point you'll know if it's something major (tranny repair) or if it was minor thing that you were/are able to fix.

hotrodjohn71

Thank you Dref00, I really appreciate your advice.