pogo

hi:
I have a 99 with 42k miles - had it since brand new. Within the past 2 months it's developed this problem shifting into 5th. That is, when going through the gears, normal driving then try to shift into 5th, it doesnt "catch". IT feels like it goes in but if I let out the clutch it will start grinding and pop out. One thing I did notice (that stopped working) was if I shifted from 3rd to 5th it wouldnt have any problem. Yesterday that didnt help anymore and now 6th gear goes in but occasionally grinds. Basically I'm going from 4th to 6th now.

I know I should probably try changing the fluid, just wanted to see if anyone here had any similar experience? thanks

also - car not really driven that hard. No banging gears, hard launches, etc. 1-4 gears are fine.

The Big Guy

I too, have a 99 6mm ordered new and have 137,000 miles on it. Since the low miles and no serious pounding, I would do an adjustment on the shifter. Check for threads on how to do it, or go to the Service Manual to direct you. I would almost bet you that this will clear the problem.
Good Luck !

cruisemon

This may seem like it has nothing to do with your problem, but I had the same issue at about 60,000 miles. I changed the transmission fluid and the problem went away. Had it begin again at 103,000. Changed the transmission fluid and the problem went away. Might try that first. Any properly rated trans fluid will work. I used O'Reilly's

Charlie

Oldvetter

I used Mobil 1 ATF in my 1998 C5 for about 50,000 miles and the transmission started grinding going into 5th and 6th gear. Changed the transmission fluid to Amsoil Torque and it immediately stopped. Now after 30,000 miles it is still okay.

Prior to 2001, the transmissions used paper blocker rings and using synthetic ATF can make them fail to synchronize the gears. Amsoil is an exception, it works.

Tron Z

If these suggestions don't give you any joy, don't overlook the shifter box mounting bushings.

5.3Avalanche

Did you end up solving your problem? I'm having an issue with my C5 not being able to downshift into 5th from 6th, and I haven't been able to find any information on here to fix it.