One tonight's drive I accidentally downshifted twice at aprox 40 MPH and the engine revved up close to redline.. with much braking effect.. should I be worried I damaged the clutches ? I noticed no issues as I continued to drive... shifts fine..

 

No it's fine. Believe me I drive mine like a rental if it hits redline the rev limiter will cut it.

 

The car is designed to take that and more as long as you are past break-in. And a couple of excursions within break-in likely wouldn't cause any problems.

 

I am concerned about the trans clutches more than the engine. I have 635 miles logged on my 2023

Maybe the aggressive track drivers can chime in on clutch wear/ damage from downshifts at too high a speed. Can the Tremec take it stride?

 

No. Its all in your Owners Manual. It will not allow downshifts or upshifts unless it is safe to do so. With the exception of break-in where you want to avoid exceeding 4000 RPM. The car will not prevent going above 4000 RPM during break in, you must do that your self. If you did exceed 4000 RPM during break in , don't worry about it, and don't do it any more. The car is not terribly fragile.

The Manual Paddle Shift system will not
upshift or downshift if vehicle speed is too
fast or too slow, and will not start from any
gear other than 1 (First) gear.
If upshifting does not occur when necessary
in Manual Paddle Shift mode, vehicle speed
is limited to protect the engine. When in
Temporary Manual Paddle Shift mode, the
transmission will automatically upshift if the
accelerator pedal is pressed all the way to
the floor.
Manual Paddle Shift can be used with cruise
control. See Cruise Control 0 218.
At maximum engine speed (rpm), auto-shifts
will occur after a specified time period to
protect the engine.
The vehicle speeds required for Manual
Paddle Shift upshifts depend on several
vehicle inputs, which will vary the allowed
upshift speed by a few km/h (mph).
To prevent damage to the powertrain,
Manual Paddle downshifts cannot be
performed above certain speeds.
The vehicle speeds for allowed Manual
Paddle shifts can vary by vehicle model or
optional equipment; such as the Stingray Z51
with Electronic Limited-Slip Differential
(eLSD) differs from non-Z51 with Mechanical
Limited-Slip Differential (mLSD).

 

All good! Enjoy it!

The computers will lock you out from damaging downshifts or over-revs.

 

I did this about 30 times this summer. I surely wouldn't be worried about one missed downshift.

 

Excellent info thanks.. I have read the manual several times, however I thought downshift / lowest gear selection for speed/rpm protection was only if you pull and hold the left paddle? For break in are we referencing 500 mile?

 

500 miles - correct

 

I guess the computer control / protection is why I can't initiate a upshift to 7th or 8th gear when doing 50 or so ? Most of my driving is off expressway so I rarely go over 65 and highest gear is usually 6th... at what speeds does the transmission shift to 7th and 8th?

 

Was it in manual or auto

 

Auto.. I have never used the M manual function

 

My C8 will shift up to 8th gear on the freeway before 70 MPH. That's in Tour mode or Mymode. If you're driving in Sport or Track mode the shift rpm may be different.

 

In automatic drive mode (D), when you pull a paddle, you will transition to Temporary Manual Mode, and all of the protections described will apply. The limits on minimum speed to manually upshift are in a table in the manual. For Z51 they are 47 mph for 7, and 57 mph for 8. For non-Z they are 50 mph for 7, and 60 mph for 8. The maximum downshift inhibit speeds are also in those tables.

Break in is 500 for the limit on not exceeding 4000 rpm, and the operator must control that. The car will still allow RPMs up to redline. Do not worry about it if you did it once or twice accidentally.

There is a break-in caution also about "lugging the engine", which is using a gear that is too high for the speed, resulting in an RPM that is very low, but it never defines what RPM constitutes lugging. But if you upshift to a gear at the minimum speed that will allow that upshift, the engine will be turning at very low RPM. I'm not saying that is "lugging" but some forum members suggest avoiding running at that lowest RPM - due to the lugging concern.

 

Note that even thought the tach shows a lower redline during break in, that's only for the display. The car will still rev to the actual redline, and downshifting will let you choose a gear that exceeds the break in redline. Once past break in, the car won't let you downshift to a gear that would let the engine exceed redline.

 

Off the top of my head I don't remember those speeds, but you're right that you can't upshift to a gear that would cause the engine to lug because rpm is so low. What rpm that is depends on the gear. If the car will let you upshift, it's not lugging.

 

The LS/LT series engines LOVE to run low revs; one of their strengths. "Lugging", in my experience, is not just running at low revs, but low revs combined with high throttle applications. This causes undue loads (and wear) on the rod and crank bearings.

IOW, something that can really only happen with a true manual transmission.

Have a good one,
Mike