70LS1Nova

So, I have a 4l60 level 5 from FLT that i bought in 2008. Might have 10,000 miles on it. I went to the track last night and when i launched with a 100 shot of NOS, it spun hard, heard a loud bang and the motor just revved like it was in neutral. Finished the run in 2nd gear. When i tried 3rd gear, i had nothing, just spinning. Parked the car for a llittle bit and headed home in 2nd gear. On the way home, i tried 3rd and it was working again. This morning, i took it out and it starts out fine and runs fine in all 3 gears (didn't try OD). When i was close to the house, I jumped on it and again, when the rpm's went up, a bang, and just spun like in neutral again. It drives and shifts just fine when i drive it normal. Any ideas what could be wrong before i pull it out and ship it back to FLT? Anyone else experience this?

mrvedit

Its hard to be sure, but this sounds like the forward sprag is failing. There have been other threads where it is intermittent before it fails completely.

Mike 02T/A

iTrader: (28)

Rolled the sprag, if you're lucky!
My car did the same thing recently. Now I'm running the FTI TH400 LVl 4.5. You'll get tired of fixing the 4L60E.

70LS1Nova

Tired of it already. Thinking 4L80E.