How durable? 05 GT automatic

[thewheelman]

I have a 07 GT500, which I bought new. It has been (mostly) a trouble free car, but have zero experience with the 4.6 GT of the same body style. I'm looking at a 2005 GT convertible, automatic, with 136k on the clock. How durable are they? I have known this car since new, but now considering buying it. I know it's been "taken care of" but the trans, a/c, electrical issues worry me. Is 136k too much? It will be driven daily about 5 months out of the year.

 

[Dino Dino Bambino]

Most 5R55S 5-speed transmissions start to develop problems somewhere between 100-150k miles but some go past that trouble free. It all depends on how the car was driven and if the fluid/filter was changed at appropriate intervals. Stop/start city driving and sitting at stoplights with the selector in D and foot on the brake pedal will shorten auto tranny life, whereas cruising on the highway will prolong it.
The 5R55S has two known weak areas: servo bore wear and a 10-spline input shaft. Fixing both isn't cheap and some choose instead to transplant the stronger 6R80 6-speed auto (with transmission harness) from an 11-14 GT.
If you're only going to drive the car 5 months per year, it might take a long time before the auto tranny starts giving you problems so just enjoy it.

 

[07 Boss]

My car has 150K in her and the majority of that has been pushing 11 psi of boost. As Dino said the tranny is probably the weakest link. I've been through 3 already but I abuse my car like a red headed step child. Besides the tranny the only other maintenance I didn't consider routine was changing out my timing components and I only did it when I had to change my front cover, but I also run a bunch of aftermarket parts. The motor is pretty stock minus the blower and cams but basically untouched as far as engine internals. Normal maintenance and love should take you far.

 

[KLJ777]

I hate the 5R55. I am on my 3rd and this one seems to be built right.
I am
500HP at the rear wheels and race 4x a year. only have 35K on her.
The trans also has bands like a minibike and they do not hold up well.