TorontoC6

I have a stage 4 RPM differential with 3.90 gears on my 2006 Z06 C6 race car with a Quaife locker. I had it rebuilt last year and changed from 4.10 gears to 3.90 gears and upgraded the coolers and fan setup after I blew the differential (ring gear detonated and blew the case apart). I don't know how many track days were on the old differential but I've put 21 days on the new diff.

Should I change the ring and pinion gear this winter or try for another season (~15 track days a year)?

Engine is a ~520HP (at the wheels) 406 LS2 with an RPM level 5 tranny. Running Pirelli DH and Continental slicks. This a track only car. I run at Mosport and Watkins.

I will be asking RPM's opinion directly but wondered what differential maintenance schedule others were following.

RX-Ben

I think an annual inspection makes sense, if you can swing it, or at least every other year, with that much power/stress. With that ratio, you are down to the C5-sized R&P gears, not that they are small, but not as beefy as OEM C6Z.

I ate away an alarming percentage of the OEM C5 27 spline trans output shaft with all of ~340-360hp/tq. I also broke a diff plate in an aftermarket diff.

I have been using an upgraded 30 spline setup that I'm sending in (to RPM) for some minor work and also to try to gauge the wear rate.

stevensa

I had ~40 track days on my diff when it was pulled apart to be inspected and have fresh bearing/clutches/seals installed. The ring and pinion looked to be in great shape. My car only makes TT3 power though, but as long as the diff doesn't see any major shock loading I don't see why the ring and pinion would need to be replaced.

TorontoC6

Thanks for the guidance. I think an inspection is the way to go.

0Anthony @ LGMotorsports

Put a 3.42 ZR1 diff in it if you want it to last.

Any of the other ratios are the smaller gear sets and yes you are going to have to replace them. Typically we went through them every 3-5 races for full rebuilds including gears but we still had a clutch pack diff too.

Bill Dearborn

One thing I noticed over the years is GM has changed their Owner's Manual to address diff lubrication. The 2008 and older manuals don't mention diff lubrication in any of the sections on performance driving but the 2009 and newer manuals recommend (right along with lubing the rear tie rod ends after each track day) changing the diff fluid after each 24 hours of track usage. I started following that recommendation on my 08 as I don't know of any diff changes that make different model year diffs unique. It may have been a GM lesson learned due to diff replacement warranty costs.

Bill