thelakeshow2k

Bought a 7 speed (previous owner installed a short throw shift kit). I noticed that shifts ARE NOT very smooth (especially 2nd and 3rd gear) when car is cold. Shifts get better after some driving.

Is this common? If so, why? Thanks.

RyanC7

Mine is at the dealer now for clutch shudder and a rear axle leak and I asked them about the same thing. I have no idea of the outcome of today if they are going to be good about the powertrain warranty or give me song and dance. I won't post dealer name until I know more, but I will update you on my car at least.

One thing is for sure, all THREE of my manual C6's were perfect in everyway.

Billy346

rrsperry

Without knowing which short shifter you have, nobody can tell you. I’ve got a MGW, and its very smooth.

JerryU

1st to 2nd common but not 3rd. In fact when below 40F some actually shift from 1st to 3rd. Have tried that and it is fine. However I usually just pull a bit harder and firm and shift at a lower rpm than normal when it's "cold." I have had a CAGS eliminator in my 2014 Z51 and now my Grand Sport so can shift into 2nd at any speed I desire. I never hear any grinding but feel the stiffer movement when cold.

Note, it's seldom below 40F in Eastern SC when I need to drive. But even then in 5 miles the trans fluid warms up and 1st to 2nd shift is very smooth. The trans gears are very large in the M7 Tremic so it won't shift as easy as a Honda Accord! I find the cue ball size shift **** I added is an overall help in the 1st to 2nd and my common 4th to 7th shift on the Interstate.

It's possible you have an alignment issue. There is an aligment procedure outlined for the OEM mechanism. However if all is fine when the trans fluid is warm, expect that is not the issue. The shift locator detents and springs are all in the trans but the shifter can prevent proper engagement.

Foosh

One person's "notchy" is another's "smooth." It's usually just a matter of perception and technique.

brooklync5

also shifts are always a bit "notchier" when the car is cold. I always appreciated the mgw shifter in my c6 because of the notchy bolt action feel. Also helped a lot when driving hard and shifting into 3rd gear. I never felt the need for an aftermarket shifter in the c7 however.

RyanC7

Well dealer says my clutch is bad and probably put hot spots on the flywheel. FML. I am the 2nd owner and all the other dude did was drive it in traffic...no racing, track, nothing. I just got the car and should have known better. I figured it was just a clutch fluid change that did help)

I know others have had the shudder issue / flywheel issue and one guy claims to have had GM pay for it all under warranty. Not sure what to do now.

I opened a case with GM....we will see how this goes.

Foosh

A bad manual driver can wear out a clutch relatively quickly on the street by constantly slipping the clutch during starts and shifts. This can be done even when driving like the proverbial "little old lady who only drove it to church on Sunday."

That's why clutch disks are generally considered wear items like tires and wiper blades.

RyanC7

Clutch has zero holding issues. The flywheel is on backorder...coincidence?? I don't think so. If the previous owner had slicks and did 5k clutch dumps at the track...sure, but he didn't. It was a daily driver in NoVa / DC traffic. We will see what they do and what we can work out with GM and worth a shot. I know people that have had it ALL replaced for free on this forum so I will "try" my luck first. I have another shop that already gave me a quote for a McLeod RST installed, and waiting for a local shop in Va as well. Fun times

mschuyler

Something I learned at Spring Mountain is that you need not slip the clutch AT ALL when starting out. Just release the clutch and do not add gas until after you are completely engaged. Idle has plenty of power to allow you to pull this off. A couple of obvious caveats are 1) Not good on a hill when you have gravity working against you. 2) Not good with traffic behind you that expects a quicker start. But all things being equal, if I can do it safely I do.

RyanC7

Yeah, I use ZERO gas when I drive a clutch...all feel and letting it out...so easy, but I am old and learned on a 69 bronco with 3 on the tree

PobreWey

The shifting is very smooth. I do warm my car up for 5 minutes when it is colder than 23 degrees.(-5c) which likely helps with the shifting.

dbirdhouse1

at about 12,000 miles on the recommendation of my mechanic and, as he said, it helps that 1st to 2nd shift measurably; not completely gone but much better and after about 15 minutes, it's completely gone...cost about 120 bucks including labor.

SilverScorp

If you car is under factory warranty, you should ask the dealership to replace the short throw shifter with an OE factory shifter.

BJ67

A short throw, short stick shifter is definitely going to increase effort.

Put a stock shifter back in and change the fluid with a correct spec full synthetic ATF and the 1-2 shift will be a lot nicer along with 2-3, 3-4, 5-6 etc

brooklync5

What does warranty have to do with it? It’s a pre-owned car.

SilverScorp

Because if you buy it with the shifter under factory warranty, the short throw shifter is covered under warranty, which means that it can be replaced with the OEM shifter at no cost to the owner.

madrob2020

Do the words "When Hell freezes over" ring a bell? No (O.K. maybe 1 dealer) dealer would repair or replace an aftermarket part for free. So if my aftermarket pro-charger goes bad or headers crack or cam fails , I'll just drop it off for a free fix on their dime?

Scarlet Corvette

I’ve noticed that if you let the C7 warm up before you drive it then you really don’t have any shifting issues. In Canada it gets cold and I’ve driven in the winter in -20 C (-4 F) temperatures. The funny thing is that when I was driving it in that cold I never had any real issues with Notchy shifting. However when the temperatures warmed up that’s when I noticed the notchey shift. Then it dawned on me perhaps it was because I was letting the car idle and warm up when it was really cold (sometimes up to 1/2 hr) but once the temps warmed up I’d basically start it, put my belt on and adjust the seat, set the radio, and take off (so the car didn’t even run 5 mins, basically when oil pressure was up I’d go). So one day I started the car and then came back out after 15 mins or so (didn’t really time it) and after the car was warmed up to operating temperature I took off and the notchey shift was gone again. If you’re not a fan of letting your car idle for extended periods then you can either double clutch, or simply blip the throttle yourself (not rev match), before shifting it into 2nd when cold and that takes care of the notchy shift too (but I just leave it warm up now so I can put my foot into it sooner). Im thinking it has something to do with the synchros and either lack of lubrication and/or friction modification properties of the ATF when cold (betcha we wouldn’t have this problem with some good old whale oil 75w-90 in there but that wouldn’t flow through a cooler very well, but I’m just a mechanic not an engineer, what do I know).
Hope this helps.