05 Automatic Transmission Issues persisting after fix

[NerdFactoryGarage]

Hello, I recently bought a 2005 mustang GT that had a couple codes related to the solenoid pack in the transmission and some other random unrelated codes. I've been working through fixing each issue on its own and finally got around to replacing the solenoid pack yesterday. for prior context the car shifts into park, reverse, drive and as well as 1 and 2 without much issue, reverse is a bit rough but never actually fails to engage. The car will not get out of first on its own though in drive. After replacing the Solenoid Pack the car seems to have made 0 change and am curious would could still be going on. we tried clearing all the codes as I had fixed other things and every single one came back immediately. Would appreciate any advice and thoughts as I'm fairly new to working on these more complicated issues myself.


I'll also add, the old solenoid pack and fluid looked relatively clean, nothing to indicate major damage. she took about 6 quarts of fluid back in when we refilled it. Car also feels super sluggish to get up to speed but does feel like in certain moments it wants to get up and go if you hammer the gas.

I'll add the codes that are currently showing up just incase something else provides insight.

P0010
P0020
P0135
P0155
P0443 - replaced vapor canister in front of car and Evap solenoid in the back
P0446
P0743
P0755
P0760
P0962
P0966
P0970
P151A

 

[Kev555]

That's a lot of codes in one vehicle, If they are permanent and i see they are not all relating to the transmission. I would check all the engine wiring looms first. Also check the electrical main plug connection at the transmission for corrosion or broken wires.

 

[DieHarder]

Problem not necessarily the solenoids. Could be the servo bores. How many miles on the car?

Most common 5R55s Transmission failures:

 

[NerdFactoryGarage]

Problem not necessarily the solenoids. Could be the servos. How many miles on the car?

Most common 5R55s Transmission failures:

shes definitely way up there in miles just over 200,000 so wouldnt be completely surprised if it was completely cooked it just seems odd due to it being able to shift smoothly when manually done and it actually going into reverse and drive as well as the fluid and solenoid pack showing no signs of material. I will say I've mainly driven manuals my entire life so im naive to autos and how they act when they're done.

 

[NerdFactoryGarage]

That's a lot of codes in one vehicle, If they are permanent Not all relating to the transmission. I would check all the engine wiring looms first. Also check the electrical main plug connection at the transmission for corrosion or broken wires.

I do plan on going through all the wiring, it's got some junky wiring going from the radiator fan straight to the battery and then off somewhere into the interior.

 

[DieHarder]

With that many miles on her you can pretty much guarantee the servo bores need work. If you need expertise probably best to take her into a transmission shop you trust to get a second opinion.. and there are plenty of uTube vids on the issues with these transmissions. Whether you use that kit or not (provided that's the problem) comes down to how well you and maybe a friend are willing to take it on. I have a 5R55s myself but she's still shifting okay so I haven't taken the plunge yet. When I do have to take it on I'll post my experience and any recommendations. Good luck.

More 5R55s transmission issues: