Hey everyone,

I've had my Cobalt for a month now and notice that whenever I upshift from 3rd to 4th or downshift from 5th to 4th, I hear this horrible crunching noise. It almost sounds like the gears are grinding. Also, it's only with 4th gear and it's usually quite loud whenever I upshift/downshift quickly or when the engine is cold. Once the engine warms up a bit, it's not as bad. The clutch is fully depressed when I shift so I know I'm shifting properly but I dont' understand why it only happens with 4th gear.

Any ideas???

J

 

Take it to the dealer & have them check it out...

 

Sounds like synchros. Same problem I had with 2nd....dealership fucked up my warranty work, the problem went from 2nd to 1st

 

do some of these transmission just have bad syncros?? Im have the same problem with my 04 redline at the moment, but my car has 49,000 miles...the dealership wont help, should i call GM about it?? This is the second time this has happened to the car, the previous owner had it repaired also....

 

Double clutch it and see if it does it. If it goes away when you double clutch it, its the syncros.

 

yea it does go away when i double clutch...should i make a claim on it??

 

Yeah.

 

Cool, thanks...talked to a saturn customer service place today, they told me I have to take it to a saturn dealer and have it checked though, thats a $106 for nothing!! I already know what the problem is...that sux, im still trying to figure a way around that

 

i have it from 2nd to 3rd. and into the shop she goes....

 

I'm taking it in for servicing tomorrow. The dealership didn't mention the word "synchros" but did mention how some "rubber" might have fallen off this "fork". I'm not a mechanic so I'm not quite sure what he means by that so maybe it makes sense to someone out there.

 

It is a synchro problem and I'm getting a brand new transmission as a result. I guess it's just easier to replace the entire transmission instead of rebuilding it.

 

They must not have a transmission expert because RedSSNA's transmission was rebuilt when it needed a new 2nd gear, 1st and 2nd gear syncro's and a new shift fork.

 

I just figured it was cheaper, in terms of labour costs, to replace the whole thing instead of having to rebuild it. Then again, I have absolutely no idea what's involved in rebuilding a transmission so I could very well be wrong!

 

I get the same **** when I go into 3rd and 4th gear. I have never had this problem with any of the other gears except those 2.

 

Ive had a little trouble getting 3rd lately, similar kind of problem. It sometimes feels like theres no where for the shifter to go, then grinds. I take it easy and pay attention going into 3rd now and havent had a problem with it yet. I know if I take it in they are going to blame it on my short throw.

 

Syncros for sure.

 

then put ur stock one back on and then bring it in.

 

Planned on doing that soon if it gets any worse

 

LSJ + F35 = great combination, rock solid but:
Top ten reasons F35 tranny needs work and synchros go away:
1. drivers shift too fast for ratio split
2. drivers cant downshift right mismatch revs and ask synchros to slow car and engine
3. drivers get into power hop
4. drivers fit short shifter, dont know how to adjust (or cannot)
5. drivers get stage 2, shift faster, mismatch revs more often and get into power hop
6. most folks cant rebuild F35 right; although you know its not hard to do it right, you just gotta have knowledge and parts (key item replace collapsible spacer on mainshaft with new nut in rebuild)
7. drivers pull too hard on shift lever (knob comes off) who's the knob
8. See 3
9. See 2
10. See 1
I have spent a lot of years in a lot of different cars. The Ecotec Supercharged engine and F35 trans with a Quaife differential is a simply awesome combination; y'all made a good choice to buy a Cobalt or a Redline...if you have trans., trouble, review how you shift the car and how you treat the car before you point fingers at GM , just maybe that finger should be pointing at you... my 2 cents.

 

Don't skip gears

 

Ill be the first to admit I love driving my car, and getting the most out of it with "spirited" driving...now the slap in the face from GM(IMO) comes when in my driveway I have a 91' Toyota tercel which I turbo'd to double its horsepower from the factory(which mean I make 160whp LOL, its a little car doesnt need much!), had a EF(90') Honda hatch with a turbo D16 making 220+ whp/tq...

Now...Ive been driving manuals since the age of 15, now 23...not claiming to be the next paul walker or anything but I drive pretty good, and I drive alll these cars the exact same!! This tranny didnt even hold up to 50,000 miles!! You can guess how many miles are on the other cars and the way I beat on em...NO TRANNY ISSUES EVER, minus the clutch changes...c'mon now, we dont buy these redlines/cobalt ss' to baby em through the gears...

U mean to tell me a 91 Tercel and a 90 honda Hatchback transmission is holding up hp/tq/abuse better than this F35(AND IN NO WAY DID HONDA OR TOYOTA EVEN PROMOTE THESE AS PERFORMANCE VEHICLES)...in no way is this logical right about now, granted im making 260whp on my redline w/this intense kit...and YES, i do downshift...YES, when racing I do shift hard(who doesnt) and YES, I have used downshifting to slow my car down when approaching lights in stuff(just like the other cars....)

I mean, maybe Im asking to much from a car they promote in the "sport compact" market/scene and support u in builds to 300+whp etc... Im sorry but Im calling this unacceptable by far, this should be able to take more abuse...

A little more clarity on these two would be nice...Although Im sure most of us do this and correlates more so to the fact that GM put a transmission designed for a turbo car with a supercharger....

Im just frustrated...this is the second time this happened to my tranny and of course as it was when it happened first, its out of the 35,000mi. warranty....maybe reason #6 is also the reason this is happening again, maybe the people didnt rebuild my transmission the right way...and ill probably have a helluva time telling them they should rebuild my tranny again, the right way...

 

Good question dom1013. Here are the specifics. #1 get out of first gear early. If you wait, say until the needle hits 6700 (needle lag, too late) or until the red shift light comes up ) also too late. By that, I mean that engine is out of the best torque range, and then there is a tendency to shift too fast. So as you engage second, the shift fork pushes the synchro against second gear and has to try to spin down to engage. If you wait the synchro can manage it better and you lose nothing. Everytime in road racing you rush the shift and then miss the gear, you lose a 1/10 on your lap time or more.

and most times with an SS Cobalt you are now dealing with incredible torque ; it is faster IMHO road racing lap times-wise , most of the time to stay out of second gear and use third, even if it drops you slightly below the torque peak in 3rd you save a shift (gain a 1/10 on our lap time)

UNLESS. you are drag racing. That is more difficult. If you want to win in a 1/4 mile, u have to side step the clutch at launch to get good reaction time, and then shift from 1st to 2nd wide open throttle, and then 2/3 WOT; WOW! that takes real practice. I mastered it on a C4 Corvette with the old 4+3 trans, found it more difficult to do with the C5 and dont dare do it on a C6 Z06. It is real hard on the car; but to do that with an SS or Redline you MUST eliminate power hop, and you have to have the shift cables aligned perfectly. Or you pay the price.

Point 2. Most drivers when they downshift 3-2 , if they do match revs increasing engine speed ( for the same given speed of the car, the engine turns roughly 1000 - 1200 rpm higher in 2nd than 3rd) they do so after they have moved the shift lever into 2nd, even though the clutch is in, the synchro is still over worked trying to spin the gear up to speed. If a driver doesnt match revs at all just dumps the clutch in and jams the lever 3-2 then the synchro has a hell of a time, it has to either spin up the engine or suffer the drive wheels locking. Nothing will stand up to that for long.

so: shifting gears up or down is a simultaneous - clutch in/3 part motion with the shift hand - out of the gear you are in , pause, (waiting for the engine revs to drop shifting up, or for the driver to blip the gas pedal to bring the engine revs up shifting down) then engage the next gear. In a rear drive car at club races you can watch newbies spin cars out as theY downshift, mismatch revs, release the clutch and lock up the drive wheels and spin out. FWD cars dont spin out as the front wheels are directionally stable, but can go straight off doing that.

When i was in high school l learned this the hard way. I had a v8 ford, my buddy had a straight 6 chevy. he could drag race way better than me as he could do perfect WOT power shifts. His engine had less torque, no power hop, and a better shifter linkage. My car had more torque, power hop and a junk shifter that i had no clue to adjust. New trannys cost 25 bucks at the scrap yard and i replaced a few.

so now you know that was along time ago but the lessons remain. The true answer is found in todays sports cars. Paddle shifting electro mechanical gearboxes (Ferrari) a work of art; sequential tranmissions (SCCA World Challenge) and in drag racing the big block amatuer racers use (still) a 2 speed powerglide transmission! If you (obviously) dont have those options, you just gotta treat the tranny nice. And by the way its amazing how few folks can rebuild the F35 properly...so they stick in new ones..hope this helps. Hope your tranny is okay. And by the way the Hurst short shifter is awful and even the B&M doesnt allow you to follow factory shift alingment procedures. If you want a "how to" to set up your shifter i can scan directions into a pdf later this week and send it to you contact me off line

 

wow...yea i read that about three times and ima have to read it about 10 more times to fully comprehend but when you say DRAG racing and making the WOT shifts, dont I need a short shifter to make those shifts?? That would damage the tranny def. hurt the tranny if u didnt succeed im assuming....and If I ever do purchase that short shifter, that pdf would be nice...starting to think it would hurt me more than it would help though...thanks

 

copy that. re-reading let me mention that it takes time for your hand to move the shift lever. so if you wait too long, the closer u are to red line the more liklely you are to go over. anyway back to the shoot out go jr!

 

Ideally when would you shift out of first gear when drag racing, when the needle is right at 5500 rpms(Though this is difficult to calculate b/c of the wheelspin)? I know due to needle lag, the rpms would be a little higher technically...but what I would be trying to do would be shift as fast as possible with out going out of the torque powerband while also trying to stay at WOT right? This would definately take some practice from the way it sounds...have you accomplished this on you F35 or this is something I shouldnt try? Im thinking I should just watch how hard im shifting from 1st to 2nd...