PROBLEM.....I think

[JayJayZ06]

First and most important I appreciate anyone who reads and helps me on this, as this is gonna be a little long. I have already recieved MUCH help about the CLB from this site, but now am worried that there is something a little more troubling....I bought my 2003 Z with 19,8XX miles on her 12/5/09. I have done extensive searching on this and other sites on the tapping, clanks, marbles, and sewing machine noises this transmission can make. I have the "in nuetral with clutch pedal unpressed sewing machine sound", which I know is normal because when clutch pedal is pressed it goes away comepletely. When driving like veeeeery slow through town (shifting into second before the CAGS kicks in), and into 3rd there is a SIGNIFICANT clunking sound (like a light "clunk clunk from inside the shifter") right when the gear is engaged coming from the shifter almost like echoing from the rear (yes I know the trans is in the rear). Heres the kicker......... this week has been beautiful here in good ol Michigan. Today was the first day I didnt let her warm up to at least halfway to normal operating temp. (I have a thing with letting my 'nice' cars warm up). After about 1 mile of driving to work, shifted through 1st, second, and in 3rd gear I hear this AWFUL whine/whirring sound coming from the shifter only under load.I shift to 5th gear and the same sound. Just a few miles and a couple of stoplights later nothing. Before I left work a few hours ago I obviously let her warm up almost comepletely and it did the SAME noise only in 1st pulling out of work and quieted down after that. The whole way home I was playing around accel/decel in with gear to try and duplicate the sound.....NOTHING. Only difference is that I swear the gear whine on accel/decel in gears in higher RPM like 3000-5000 seems to be much louder and a slight tapping......maybe a mental thing. Either way I am freaking out!!!! Any Ideas? Trans fluid and rear end will be changed in about 10 hours hopefully, but doubt that will help. Thanks in advance for any input....I'm thinking rear end. FYI- a few days ago during a hard 2nd gear pull the "active handling warming up" thing popped up and it felt like it wasnt pulling nearly as hard as it has before........after that "warmup comeplete" and all good. Searched on that as well but nothing came up about my situation..... car was drove probably 10 miles before I got on it. <-- thought that was something to ponder.

 

[WB6HRO]

Try the easy things first. Change the differential and transmission fluids to Redline, the stock oil is not synthetic. While it's on the lift have them look at the drive shaft tube rubber isolators.

 

[c4c5specialist]

HI there,
Actually, the differential is factory filled with synthetic oil.

I would suggest draining the fluids into a magnetic dish and see what kind of metallic particles are there.

A black tint to the transmission fluid is NORMAL, just so you know.

Allthebest, c4c5

 

[Edmond]

From my reading and research, it seems like the C5 Z's are quite prone to sounds. The T-56 internals also seem to be a weak point in the transmissions.

However, one thing that I have noticed is that after I changed the stock shifter over to an MGW shifter, I have not had trouble engaging any gears. The 2-3 shift is very precise where as before with the stock shifter, I had to "find" 3rd gear.

Seems that the noise from the front which goes away could be the throw out bearing. It's a little piece that's $12 to replace but takes a lot of work to do it.

The shift forks are weak in the T-56, aftermarket ones such as the unit from RPM Transmissions come with heavier duty hardware.

Keep that clutch fluid clean! Use a baster to take out the oil fluid, refill it to level and then pump the clutch pedal about 30 times. Check the clutch fluid level again and repeat if necessary.