nascar57

I have noticed lately that if I rev the engine up past 3000 and shift into 2nd gear, it will often grind a little before going in. All other gears operate normally. Sounds like the synchro's are getting worn. Other than a rebuilt, anything that can be done? I plan on changing the fluid to synthetic to see if that helps any.
I always check here on the forum to see who is recommended for rebuilt tranny's etc. Who do you guys recommend??

2slicks1vette

You'll probably get better results posting this in Tech.

Perhaps try adjusting the shifter too.

robert miller

RPM for sure here. You may want to check with Bret, BLOWNBLUEZ06 are Nick, BLOWNZ06 both did have a t6060 trans for sale at a very good price... Robert

nascar57

Thanks Robert. I'll check. Any other suggestions out there?/

cdkcorvette7

Your second gear synchro is going out. Common problem... No way to fix that other than tearing down the transmission or buying a used one from a part-out or upgrade situation and swapping them.

New trans fluid may help you delay the inevitable; what year is your C5? If you have a 97-00 you have paper blocking rings and there are some on here that say you should not use synthetic with those as they will deteriorate faster with it. This is a much debated topic so you should search and decide for yourself; I wouldn't run synthetic in a pre 01 C5 but that's JMHO.

Also, if you learn to match revs while shifting into second you'll eliminate the need for a synchronizer and it's easier on your transmission.

GL

Normseven

What do you mean by match revs while shifting into 2nd, tks.

cdkcorvette7

Here you go: http://www.drivingfast.net/car-contr...th-driving.htm

Scroll down to the blurb on rev matching. Think of it as manual synchronization of engine and gear speed...I do it all the time out of habit... You burn a little more gas but the shifts are smoother.

SCM_Crash

Yeah, I agree. It sounds like a synchro issue.

Rev-matching is when you make sure the engine RPM directly relates to the speed at which you're driving and the gear you're shifting into. (I could be wording this wrong)

Basically, if you're shifting from 3rd to 2nd at 40 MPH, you need to rev up to the RPM your engine would be at 40MPH in 2nd gear. Then shift into 2nd. This is normally done with a quick 2-step action. Rev-matching saves your transmission a lot of wear and tear, helps your shifts be smoother and you don't send as mcuh energy from the rear-wheels back to the engine which causes unnecessary wear and tear on the motor as well.

Rev-matching should be done in both up and down shifting.

As an example (please keep in mind I have a Z06, so my gearing is a little different):

- I'm driving at 75MPH in 6th gear and my engine is at 1950 RPM.
- I decide to pass a car, so I down shift to 4th gear.
* To do so, I'll need to rev up to approximate 4000 RPM so that my down shift to 4th gear is smooth and the synchros don't have to do so much work so quickly. *
- I rev to approx 4000 RPM by blipping the throttle.
- I shift into 4th gear and let off the clutch.
* In theory, the car should be at the same RPM I revved to. *
- I give the car gas and pass the car that was in front of me.
- I slow back down to 75MPH still in 4th gear.
- I now decide to shift back to 6th gear.
* To do this, once I push the clutch in and put the shifter in the neutral position, I'll want to wait until the RPMs have fallen almost back to 1950 RPM so I can shift back to 6th gear. If my RPMs drop below 1900 RPM, I'll give the throttle a little gas to get it back up before shifting.
- I push in the clutch and put the shifter into the 6th gear gate and ease it in. If the RPMs match the speed for that gear, the shifter should pretty much fall right into that gear with a small amount of effort.


Perhaps I'll make a video tutorial on proper rev-matching. It does require some practice, but with a little work it will become second nature and you'll save a lot of life on your transmission.

Also, please know that you'll see a lot of "heal-toe" tutorials for rev-matching. This is another type of rev-matching, but don't do this for daily driving. It's pointless and not at all worth the trouble for daily driving.

EDIT: One more thing to add... You shouldn't down shift to slow the car down. Transmissions cost more to replace than brake pads. Some people do it because they like the sound, but it's just not good for the transmission. Down-shifting is good for when you need to go faster to a point that you need to be in a lower gear or if you're about to make a turn that you need to brake for. The last reason you should down shift is to slow the car unless your brakes are not working right.

nascar57

I kind of figured it was the synchro. Mine is a 2001 so synthetic fluid should be O.K.?? Car has the original clutch and 65000 miles. Any recommended rebuilders??

cdkcorvette7

Synthetic is fine. I put synthetic in mine around 40K miles ago and have been pleased with it. Any well known high quality brand will work, don't go cheap on this. You don't do it very often. If you want help deciding use advanced search for "which transmission fluid" and enjoy all the redundant "my trans fluid could kick your trans fluid's a$$" posts. There's also nothing wrong with gm recommended. At 65K miles any new trans fluid will make shifting much more enjoyable.

If you want the best rebuilder go with RPM transmissions in Indiana. Do NOT use anyone that has not done a prior rebuild on a T56.

blacksedan87

RPM is the only way to go - you can choose to all the way up to a Level V modded transmission. I run a Level V set up as a M12 (Z06 - that's pronounced ZED aught six....I love that!) in my convertible. Shifts are butter smooth and the ratios are different.

RPM has the whole customer service thing really dialed in!

Rick@RKT Performance

There are 2 ways the 2nd gear could grind. First is the worn shift fork pads. They can deform over time and have too much play. Second is if that synchronizer teeth and engagement teeth have been missed repeatedly and worn. Either way, the transmission needs to be rebuilt. Let me know if you would like a quote.

robert miller

Also go by what this guy is telling you here. Really knows what he is talking about here...As far as rearends and trans would put him up with anyone... Rick love the c6 z06 rear in the car runs like a dream man.....

Rick@RKT Performance

Thanks for the kind words Robert. I really take pride in what I do and I'm little more personal on my builds with individual customers. I take calls 7 days a week for any drivetrain concerns or needs. And as you already know I stay in touch and communicate through out the build.