Transmission Issue

[MRGEORGE077]

I’m still sorting out the Shelby American 289 slab side that I took delivery on several months ago. The current issue is as follows:

Up until two weeks ago, I had only driven the car short distances but on this occasion, I decided to drive the car for an extended period of time, that day it was about 101° during the drive the engine never exceeded 195° and the oil temperature never got above 185.

The Cobra has installed a Borg Warner T10 transmission. After about 1 1/2 hours driving at highway speed I went to down shift into third to stop at a red light. When I pulled it out of fourth the transmission totally locked up, and I could not get it into any gear. I pulled over to the side of the road and after a sitting for a short-period time I got it back into first gear from that point I ran through the gears to be fourth, but the very next time I went to down shift the same problem happened. Once again, after pulling off the road then sitting for a few minutes I could get into first ran to fourth and keep it there until I reached home.

The next morning the transmission was working fine. I drove it to a repair shop where I was having some heat retardant insulation installed. I told the mechanic about the problem and we all kind of felt it was an external heating problem, hydraulic fluid boiling, and that’s what caused the transmission, or clutch, to seize up. We hope that the installation, we were installing, would fix it.

A week later when driving the car to the trim shop, which was only about 15 miles, we experienced no problems. The same is true when I went to pick the car up, yesterday, from the trim shop to drive it back to the mechanic, there was no issue. After visiting with the mechanic for about an hour and a half, I started to drive the car home but only get half a mile when the transmission totally froze this time when I pulled it off to the side of the road and set for a while it would only go into reverse, first and second but third and fourth were totally locked out. We trailer it back to the shop where it now sits, maybe after sitting over the weekend it will work again.

Does anybody have any ideas what possible might be wrong with this transmission?