Running rough in 6th gear

[Valkyrie14]

My 2014 SS has been driving rough in 6th gear. When I am going 55-65 mph and I shift into 6th the engine has a hitch, a hesitation, something. It tends to really do it under a load, like going up one of the 100 hills in my neck of the woods. Not sure if it is a misfire or something else. The engine is at about 1500 RPM when it does this. When I shift back into 5th all runs smooth again. I live in rural WI and I am restricted to <65mph most days. I have to stay in 5th at 2000RPMs. I have had the car for about a month. I am trying to find out if 60 mph is just too slow for 6th gear or if the engine/manual transmission is telling me something.

I recently checked all of my plugs and all looked good, worn but wearing the way they should.

I changed all of my fluids, the trans had what looked like ATF, even though the dealership told me 80/90W is what to put in the trans. So I did, I am pretty sure that not all of the ATF came out so there is a mix of ATF and 80/90W in the trans. Before doing this I googled it and many posts said mixing ATF and 80/90W wouldn’t hurt anything. I don’t know if this is related to the 6th gear issue, but I thought it may be.

There are LT headers as well, from previous owner. Don’t know brand or skill level of who put them on. I don’t think there is any leak and they sound great. Again, listing to offer variables for the problem.

Last thing, there is a ZEX Blackout nitrous system on there from the previous owner. Same story as headers. It appears to have been installed properly.

Any ideas about the rough engine?

[pnwdan]

Your six speed uses a fluid similar to atf and not gear oil. Regular gear oil is too thick. Stock geared, you shouldn't be in 6th until 70mph + . That coupled with lugging the engine in 6th would cause your issue.

I switched to Royal Purple Syncromax in my six speed and I'll never use anything different.

[Valkyrie14]

So it doesn’t hurt anything to run at 2000rpms in 5th for 20 miles?

Good to know about the Royal Purple, I may do a flush and change it out completely.

[LimaCharlie]

Sounds like the symptoms of 'lugging' the engine. 55 MPH is too slow for 6th gear. The engine has to work harder to maintain speed at such a low RPM. Don't lug the engine for a long time because it can overheat and possibly cause pre-ignition.
The stock 5th gen Camaro SS manual transmission is a Tremec TR-6060. It uses ATF. I don't know why the dealer told you otherwise.

[Valkyrie14]

My local dealer ship are experts in Silverados, but I haven’t seen a camaro there ever. I assumed he looked it up. I am glad to hear that it is not an issue with my engine just how I drive it. I’m easier to fix.

[Greenhornet2]

The worst thing you can do for an engine is to lug it. 55-60mph is ok going down a hill or on a super flat area where you barely have any throttle input but as soon as you hit that hill you need to downshift. It is much better for your engine to be higher in the rpm range while going up a hill, 4th would be even better your engine will last much longer. You WILL blow an engine lugging it like that in time. 2k rpm all day long is perfectly fine 2500-3k rpm even better up a hill.

[Valkyrie14]

Good to know. My last manual was a 2000 beetle, a little difference in HP. Still getting used to this beast.

[GAD]

Mines an automatic, so completely different transmission. But even on the interstate she doesn’t see 6th gear.

[Ashen L99]

Originally Posted by GAD

Mines an automatic, so completely different transmission. But even on the interstate she doesn’t see 6th gear.

What? Do you drive 60 everywhere? When I’m sitting at 75 in sixth it’s at 1900 RPMs which is fine so.....?

OP consider doing 3.91s gears from GM. You’ll get an overall performance increase, and sixth gear will be usable on the highway under speeds of 75-80+.

[GAD]

Originally Posted by Ashen L99

What? Do you drive 60 everywhere? When I’m sitting at 75 in sixth it’s at 1900 RPMs which is fine so.....?

OP consider doing 3.91s gears from GM. You’ll get an overall performance increase, and sixth gear will be usable on the highway under speeds of 75-80+.

Nope, mine has the same “chugging” feeling In 6th that the op is describing anywhere under 80mph. And anything over 80 where I used to live is considered reckless driving. So my interstate cruising speed has always been about 75-78mph and that’s 5th gear stuff.

[gtstorey]

I would also be a little concerned about the tune since it has LT headers. It might not be running as well as it might at slower rpm's.

[Valkyrie14]

I have a tune on it, the car came with a SCT Flash and has a couple of custom tunes saved on it, one with nitrous and the other without. I am currently running the without tune. No idea who did it or when it is from. I am debating working with a custom tuner with the SCT and getting a fresh tune after a tune up versus going to a dyno shop in the twin cities and getting a tune there. Never did a dyno with my last vehicle because I was more or less happy with the tune I got from a Diablo custom tuner.

I have been driving around keeping things at 2000 RPMs and everything is smoother. The reason I was shifting trying to stay at 1500 is the drone from the exhaust. The previous owner put on an aftermarket exhaust but I can’t tell what it is. The rumble is beautiful, but the drone in the interior is making me go deaf. I have been wondering if getting a Borla would lessen the drone while keeping the beautiful sound.

[Greenhornet2]

My borla has no drone, but if you are happy with the exhaust otherwise j pipes will help with drone abs won't cost as much as a new exhaust. A dynotune is never a bad thing. I might be a little concerned that there's a saved time for nitrous, means the prior owner probably ran nitrous hopefully didn't hurt anything.

[Valkyrie14]

I am concerned about the nitrous. The tank is empty and of course the dealer said the previous owner never used it. I am probably going to take it off and sell it. I will look into j pipes, are there any out that are bolt on? I don’t have a welder I trust.