700r4 - over-run clutch - upgrades ?
11-14-2018, 05:55 AM
#1
Melting Slicks
Thread Starter
700r4 - over-run clutch - upgrades ?
I ran my C4 (carb 383/ 700r4) Hillclimb car last week at a once a year closed off street track.
I have run this track previous years before the trans was built (but still using a 3200 converter) this year was the first time since the trans was built.
It was doing a weird thing getting off the throttle approaching the fastest corner in 3rd - the idle would drop to almost idle and the car would be freewheeling thru the corner. When the speed dropped enough it would re engage and the revs would come back up. I have run this track several times before the trans was built and it didnt do this. The track I normally run at has shorter straights and lower speeds so it hasnt done this before.
I spoke the guy who built the trans - he sd it will be the over-run clutch slipping, he sd the clutch isnt designed to engine brake a 1400 kg car at 160 kmh. He sd they built a 4l60 recently that had upgraded stuff including the over-run clutch plates but wasnt sure exactly what the deal was with them.
So Im thinking, well the gearbox didnt do this previously, what is the difference now ? When the box was standard I was using Castrol Transmax synthetic, the built box is using Dex3 fluid. Could the slipping over-run clutch be caused by the Dex3 fluid ?
Anyone with any input would be appreciated - can the over-run clutch be upgraded ? Can the type of fluid cause this ?
I have run this track previous years before the trans was built (but still using a 3200 converter) this year was the first time since the trans was built.
It was doing a weird thing getting off the throttle approaching the fastest corner in 3rd - the idle would drop to almost idle and the car would be freewheeling thru the corner. When the speed dropped enough it would re engage and the revs would come back up. I have run this track several times before the trans was built and it didnt do this. The track I normally run at has shorter straights and lower speeds so it hasnt done this before.
I spoke the guy who built the trans - he sd it will be the over-run clutch slipping, he sd the clutch isnt designed to engine brake a 1400 kg car at 160 kmh. He sd they built a 4l60 recently that had upgraded stuff including the over-run clutch plates but wasnt sure exactly what the deal was with them.
So Im thinking, well the gearbox didnt do this previously, what is the difference now ? When the box was standard I was using Castrol Transmax synthetic, the built box is using Dex3 fluid. Could the slipping over-run clutch be caused by the Dex3 fluid ?
Anyone with any input would be appreciated - can the over-run clutch be upgraded ? Can the type of fluid cause this ?
