91 six speed
Thread Starter
Drifting
Joined: Oct 2006
Posts: 1,328
Likes: 14
From: Stafford Connecticut
91 six speed
I took a test drive in a 91 six speed today.I was going to buy but noticed a problem with second gear. If I drove it slow it would shift into second O.K. but if I took off fast it did not want to go into second. Any ideas of what the problem could be?The car was in real good condition and the price was good.The clutch seemed to grab at the proper take up.
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Safety Car
Joined: May 2006
Posts: 4,290
Likes: 140
From: Salem NH
'91 is my favorite year C4, but common sense tells me to "buy the newest vette you can afford in the best condition".
In 2005 when I was looking to buy a C4 (was a fbody man) I couldn't touch a '91 for under 9k unless it was a rag. Talk about a failing market?!
I lost my shirt on my car and it's still not "right".
-- Joe
Thread Starter
Drifting
Joined: Oct 2006
Posts: 1,328
Likes: 14
From: Stafford Connecticut
I understand what your saying Joe.I just don't like the Optispark.I can work on the first gen small blocks with no problem.I wanted to make a 383 or 427 out of the 91 vette.
6th Gear
Joined: Dec 2008
Posts: 6
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From: Windsor VA
Unfortunately, under the driving conditions you describe, it doesn't sound like the CAGS. CAGS prevents 1st to 2nd under light loads and light rpms. When you get on it or up the revs it should allow 1st to 2nd shifts. I'd be concerned about this if your description is accurate.
Le Mans Master
Joined: Feb 2005
Posts: 5,146
Likes: 3
From: The Motor City
to the OP, if you like the car and the rest looks real good, ask the owner if you can have either a local wrench look it over or a dealer and pay for the hour time. This will answer all your questions, and if the owner is straight he shouldn't have any problem w/this.
Le Mans Master
Joined: Jan 2008
Posts: 7,030
Likes: 10
From: Edmonton, Alberta
Unfortunately, under the driving conditions you describe, it doesn't sound like the CAGS. CAGS prevents 1st to 2nd under light loads and light rpms. When you get on it or up the revs it should allow 1st to 2nd shifts. I'd be concerned about this if your description is accurate.
You should also see the idiot light flash "one to four" on your dash
Jim
Le Mans Master
Joined: Sep 2003
Posts: 5,874
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From: Littleton CO
Unfortunately, under the driving conditions you describe, it doesn't sound like the CAGS. CAGS prevents 1st to 2nd under light loads and light rpms. When you get on it or up the revs it should allow 1st to 2nd shifts. I'd be concerned about this if your description is accurate.
You should also see the idiot light flash "one to four" on your dash
Jim
Edit - CAGS is still an idea worth checking out, especially if you're new to the 6 speed. Drive it again, keeping in mind the conditions which trigger it; IIRC those are <20% throttle and <2000rpm or thereabouts. I'll check at home later if someone doesn't beat me to it.
Last edited by jrp; Dec 17, 2008 at 02:31 PM.
Race Director
Joined: Nov 2003
Posts: 12,221
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From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
When you say driven quickly vs slowly, does that mean briskly vs slowly -- or near WOT vs quickly?
When/if you drive it again, try different shift points and throttle openings. I have the feeling it is CAGS -- since it will shift into 2nd.
Note: The defeat kit sold by MidAmer (or other vette specialists) is a dummy "slug" that fits between the stock plug. The CAGS plug only needs to be unplugged to defeat it's operation. The slug just keeps it clean in case you want to reuse that POS someday. Ducktape will work too.
CAGS is an electronic switching mechanism that blocks the path to 2nd gear. Any other gear can be selected when it activates. For example, you could shift from 1st to 3rd gear. It's supposed to make it slide easily over to 4th when you pull straight back.
I hate it. Mine's defeated. The plug is on the side of the transmission and is very easy to unplug.
Last edited by GREGGPENN; Dec 17, 2008 at 02:52 PM.
Thread Starter
Drifting
Joined: Oct 2006
Posts: 1,328
Likes: 14
From: Stafford Connecticut
Thanks for the replies guys.I thought it could be the hydraulics or maybe the way I was driving it.I had the salesman drive it and he was scared of the grinding also. He said he would have it checked out and get back to me .No word yet, I did find a site on the Internet of a company that rebuilds these for a living,he seemed to think it was the second gear synchros.He suggested that if I really liked the car to offer them a lower price to cover the trans problem.He said I could buy a brand new trans on E-bay for $1400.GM sold off all their unused stock of ZF6 spds.Sure enough I found them for that price.Just got to decide what I want to do.
Race Director
Joined: Nov 2003
Posts: 12,221
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From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Thanks for the replies guys.I thought it could be the hydraulics or maybe the way I was driving it.I had the salesman drive it and he was scared of the grinding also. He said he would have it checked out and get back to me .No word yet, I did find a site on the Internet of a company that rebuilds these for a living,he seemed to think it was the second gear synchros.He suggested that if I really liked the car to offer them a lower price to cover the trans problem.He said I could buy a brand new trans on E-bay for $1400.GM sold off all their unused stock of ZF6 spds.Sure enough I found them for that price.Just got to decide what I want to do.
Where was that description above? Did I miss it?
Definitely not CAGS. Either 2nd sychro or clutch hydraulics. If fluid is present and other gears don't grind, probably not hydraulics though.
Check clutch pedal travel. If you SLOWLY let the clutch out/in, does the engagement point change? IOW, is the system bleeding pressure as you use clutch?
Check fluid level (located on firewall near battery).
(I did notice new ZF's going for $1,500ish on eBay. NOS too. And, with new stick too. Not a bad deal. Major bargaining chip on price too. Ask them to quote their cost for replacement!)