- Oct 19, 2002
Hi Steve, thanks for asking.Have you had a chance to run your new setup? Following your thread & gotta ask...
Yes, I ran the new setup at the track last month. I only got two passes. The first pass was just a shakedown run, I slowly rolled off the line, gently shifted into second gear, then punched it! I went full throttle in second gear, did a quick shift into third, held full throttle to the top of third gear then shut it down. Despite the soft launch it still went 108 MPH in the 1/8th!
The second pass was better, the weather was cold and the track had no traction.
2.1 60' with much wheelspin
1/8th no data
1/4 10.77 @ 145.799
Def making some power, def not hooking up.
At the turnaround point the car did something weird, I felt the rear tires skip and hop a little. It felt like a welded center diff! But it was short and quick I checked the driveline in the pits but everything seemed normal, all 4 tires could be rotated independently as best as I could tell, so I packed up and drove it home. The trans also started making a gear whine noise in first gear. The next day I checked the trans fluid and found fine metal dust mixed in. Something's not right. So I pulled the trans and inspected it, found slight damage in several areas and one piece that stood out like a sore thumb.
The center diff spider gears had locked up and seized on the shaft. Two of the gears had seized so bad they could only rotate 1/4 turn and they would not slide off the cross shaft. They're supposed to spin freely. I compared the blown center diff to a good stock diff that I had sitting on the shelf, and I also compared it to an old Shep 4 spider diff from my last trans. Side by side it was clear where my new supposedly 'Unbreakable' 4 spider diff had failed. It didn't break, so yeah it's 'unbreakable', but the lack of attention to proper oiling is what killed it with only 2 months of use. I'm not naming any names yet since the warranty on this part is still in dispute.
For the sake of comparison, my previous 4 spider center diff was a Shep center diff. It lasted almost ten years. I looked up the receipt from Shep, I had his diff in the car since November 2003. It held up to dozens of drag races per year with numerous 1.4 to 1.6 60' times, withstood frequent wheelhop, burnouts and over 25 thousand miles of daily driving. It held up to dozens of ten second passes. It was the diff that carried me to the 14b record and nearly got the 16G record on it.
OTOH The new supposedly 'unbreakable' cross shaft blew out in less than
2 months with only two dyno sessions and 3 launches, and one of those
launches was on street tires in the rain! In my opinion the new diff major weakness is that it can't handle big power and front/rear wheel speed differences at the same time.
Like I said, I'm still exchanging emails with the guys who made the diff, I have no idea how this is going to end up. I really hope I don't end up with a $1100 paperweight!