I have been experiencing the problem with the overdrive not engaging once the car is warmed up and have seen mention of using in Redline MTL to help put off an expensive OD rebuild. I have replaced the fluid with Castrol ATF type F fluid (and cleaned the screen filter) and didn't see any improvement. I have pulled the solenoid off ,connected it directly to the battery and let it warm up then tried blowing through it to find any bleed through as was suggested by someone and couldn't get it to fail.

When I talked to the tech rep at Redline he suggested MT90 would be even better than MTL since the problem is when the car is warmed up and this product would have a higher viscosity.

Ambient temperatures typically bottom out about 15 degrees F ( although it sometimes gets down around 0), summer temps are frequently 90-100. I'm not too worried about hard shifting if it is cold since I have another vehicle to drive it it is too bothersome in very cold weather.

My main concern is that I don't want to use something that will harm the transmission or overdrive due to incorrect physical properties of the fluid.

Does anyone have any experience using MT90 rather than MTL for this application?

What are your thoughts on this ?

Also if there are some other tests that I can perform to nail down whether the solenoid is at fault that would be great to know as well.



I appreciate any information you can give me on this.