Wilkinson has an effort underway to reproduce transaxles for Panteras, GT40’s, and similar cars. The new transaxle is called GTT (Gran Turismo Transmissions). One of the components in the new transmission is the differential and he already has some of them in hand. He opted for a differential with a higher level of performance. They are 70% locking versus 40% that came in our cars. The GTT differential uses special clutches and beveled washers under high pressure to get the extra locking.
He needed to test his new differential and asked if I would be willing to put one into my 74 Euro Pantera. I agreed and we planned out the swap. I pulled the transaxle from my car and took it to his shop and prepared it on a special stand for the new GTT differential . The next day they had the differential installed in my ZF case within a couple of hours. I took my ZF back home, put it back in the car, and have been driving it since then.
Thus far, the new GTT differential has two notable characteristics compared to my 50 year old unit. The first thing I noticed is that a bunch of slop was gone. Previously when driving at slow and steady speeds the car tended to lunge. Wilkinson examined my old differential and noted that the clutches were worn (.050” on one and .060” on the other), and there could be wear on the spider gears as well. The other thing I have noticed is the increased locking that is now 70%. The car feels more sporty with the improved traction.
Here are photos of the new differential. The last photo shows it installed in my ZF.