Update on ZF 6-speed synchros worn
Thread Starter
Melting Slicks
Joined: Aug 2000
Posts: 2,618
Likes: 5
From: Overland Park KS
Update on ZF 6-speed synchros worn
I had posted a message in the thread: http://forums.corvetteforum.com/zerothread?id=545626
1995 Convertible, 75K miles, new SPEC stage II clutch installed last year.
The tranny requires high effort to get into reverse about 50% of the time and about 10% of the time getting into first. I eventually had the transmission removed and shipped to Standard Transmission & Gear in TX (standardtransmission.com). Both my shop and Standard Transmission have been great, working through this problem with me...
I should have the final diagnosis on Monday but preliminary inspection has found the transmission may in fact be okay. Whether they find anything worn and needing replaced OR find that it's okay, it appears to Standard Transmission that the high effort may be due to the hydraulic clutch system not working properly.
I know I shouldn't post "preliminary" findings but I figured with the weekend upon us, some of you having trouble getting into certain gears should check your hydraulic clutch system asap. It's probably a difference of about $1,000 between having the synchros replaced and having the master/slave cylinders replaced. Or in my case it could be $400 more to also replace the master/slave cylinders :(
I'll keep everyone updated next week...
1995 Convertible, 75K miles, new SPEC stage II clutch installed last year.
The tranny requires high effort to get into reverse about 50% of the time and about 10% of the time getting into first. I eventually had the transmission removed and shipped to Standard Transmission & Gear in TX (standardtransmission.com). Both my shop and Standard Transmission have been great, working through this problem with me...
I should have the final diagnosis on Monday but preliminary inspection has found the transmission may in fact be okay. Whether they find anything worn and needing replaced OR find that it's okay, it appears to Standard Transmission that the high effort may be due to the hydraulic clutch system not working properly.
I know I shouldn't post "preliminary" findings but I figured with the weekend upon us, some of you having trouble getting into certain gears should check your hydraulic clutch system asap. It's probably a difference of about $1,000 between having the synchros replaced and having the master/slave cylinders replaced. Or in my case it could be $400 more to also replace the master/slave cylinders :(
I'll keep everyone updated next week...
Melting Slicks
Joined: Mar 2003
Posts: 2,472
Likes: 0
From: Toronto ONTARIO
Re: Update on ZF 6-speed synchros worn (bogus)
mine went while cruising in 6th on the way to school 3 yrs back. 6th gear synchro was white hot-melted... destroyed quite a bit. never been the same since then... with the car off it wont even go into any gear... gotta shove it real hard. Drives notchy but still driveable. If i knew what i know now.... i would have had it properly rebuilt. had no idea who rebuilt it and payed large >$2500. Sucked ever since. I would have went to the ZF rebuilders if i knew... :sad: :nonod:
oh and my guess was that there wasnt enough fluid in the tranny, only way the synchro could burn out i guess....
oh and my guess was that there wasnt enough fluid in the tranny, only way the synchro could burn out i guess....
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
Re: Update on ZF 6-speed synchros worn (DieL)
the best, the god of all things ZF, you want http://www.zfdoc.com
Thread Starter
Melting Slicks
Joined: Aug 2000
Posts: 2,618
Likes: 5
From: Overland Park KS
Re: Update on ZF 6-speed synchros worn (KCvetteowner)
Alrighty then!!!
Here's the damage:
1st gear high effort 10% of the time - no tranny wear at all. All due to clutch hydraulics issue.
Rear gear high effort 50% of the time -
$308.17 - reverse gear main shaft
$265.84 - reverse gear synchro sleave
$686.87 - syncro kit (if anyone needs the 1-6th synchro gears I'll sell each gear separately for $100.00 I'm stuck buying the whole kit)
$138.80 - rebuild kit
$400.00 - labor
-------------------
$1800 roughly.
$250 - shippping to/from Kansas City to Texas
$600 - labor to remove/reinstall transmission
Hydralic clutch system will be inspected now...probably $200-$400 additional.
So if you have trouble getting into reverse save up about $2k. Yes they looked at the TSB on the reverse shift complaint and it doesn't apply when your reverse syncro teeth are squared off...
Total: $2800-$3000 depending on hydraulic clutch repair cost.
[Modified by KCvetteowner, 3:20 PM 5/8/2003]
Here's the damage:
1st gear high effort 10% of the time - no tranny wear at all. All due to clutch hydraulics issue.
Rear gear high effort 50% of the time -
$308.17 - reverse gear main shaft
$265.84 - reverse gear synchro sleave
$686.87 - syncro kit (if anyone needs the 1-6th synchro gears I'll sell each gear separately for $100.00 I'm stuck buying the whole kit)
$138.80 - rebuild kit
$400.00 - labor
-------------------
$1800 roughly.
$250 - shippping to/from Kansas City to Texas
$600 - labor to remove/reinstall transmission
Hydralic clutch system will be inspected now...probably $200-$400 additional.
So if you have trouble getting into reverse save up about $2k. Yes they looked at the TSB on the reverse shift complaint and it doesn't apply when your reverse syncro teeth are squared off...
Total: $2800-$3000 depending on hydraulic clutch repair cost.
[Modified by KCvetteowner, 3:20 PM 5/8/2003]
Le Mans Master
Joined: Jul 2001
Posts: 5,297
Likes: 0
From: Stamford VT
Re: Update on ZF 6-speed synchros worn (KCvetteowner)
Ugh. I'm dreading my upcoming situation. This damned car gets harder to shift DAILY, but nothing else indicates hydraulic problems. Shifting into any gear (including reverse) when stopped is completely effortless, but when driving the car, 1st through 4th can be smooth sometimes, and a royal horse other times.
I hope like heck all my trans needs is syncros. :-/
I hope like heck all my trans needs is syncros. :-/
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Thread Starter
Melting Slicks
Joined: Aug 2000
Posts: 2,618
Likes: 5
From: Overland Park KS
Re: Update on ZF 6-speed synchros worn (Jim85IROC)
Ugh. I'm dreading my upcoming situation. This damned car gets harder to shift DAILY, but nothing else indicates hydraulic problems. Shifting into any gear (including reverse) when stopped is completely effortless, but when driving the car, 1st through 4th can be smooth sometimes, and a royal horse other times.
I hope like heck all my trans needs is syncros. :-/
I hope like heck all my trans needs is syncros. :-/
I should end up with brand new 1-6th gear synchros since you have to buy a complete set even though they are only replacing the reverse. I'll sell you the synchros you need for $95 per gear. It's $686.87 for the whole set.
Melting Slicks
Joined: Jun 2002
Posts: 2,168
Likes: 16
From: Phoenix AZ
Re: Update on ZF 6-speed synchros worn (jburnett)
I'm having trouble getting mine into 3rd and 5th and also getting some "slop" or "lash" in my ZF. I was going to pull mine out and have it shipped to Bill at Zr51 performance since I've heard he's the guy and then I found out that he's located in Cave Creek, AZ only about 25 miles away! I talked to him a few days ago and he's going to look at it next week. :cool:
Thread Starter
Melting Slicks
Joined: Aug 2000
Posts: 2,618
Likes: 5
From: Overland Park KS
Re: Update on ZF 6-speed synchros worn (vetracer)
I'm having trouble getting mine into 3rd and 5th and also getting some "slop" or "lash" in my ZF. I was going to pull mine out and have it shipped to Bill at Zr51 performance since I've heard he's the guy and then I found out that he's located in Cave Creek, AZ only about 25 miles away! I talked to him a few days ago and he's going to look at it next week. :cool:
