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SAAC Forum => SAAC Forum Discussion Area => Topic started by: Scottmain54 on June 24, 2026, 07:33:22 PM

Title: GT500 tranny leaking
Post by: Scottmain54 on June 24, 2026, 07:33:22 PM
Hi all. My 68 GT500 will occasionally leak out lots of fluid while sitting in the garage. I think the front seal is bad and am soliciting info to find a good shop in the Daytona beach region. It's been decade's since it was overhauled. Has anyone had a good experience with transmission work done around Daytona Beach?  Anyone to avoid?  Thanks
Scott
Title: Re: GT500 tranny leaking
Post by: pbf777 on June 25, 2026, 11:11:41 AM
    I would advise a sum of diagnostic observation before any disassembly in order to attempt to determine where the leakage might actually be emanating from.  ;)

    Yes, the front input shaft seal could be an issue, but the fluid level (at rest) is normally below this position, so any leakage being presented post a duration of non-usage would have had to accumulate for an interval somewhere else before dropping to the floor.    :-\

    Scott.
Title: Re: GT500 tranny leaking
Post by: WT6066-2600 on June 25, 2026, 12:09:42 PM
C6 automatic or 4spd?
Title: Re: GT500 tranny leaking
Post by: roddster on June 25, 2026, 12:33:48 PM
Quote from: WT6066-2600 on June 25, 2026, 12:09:42 PMC6 automatic or 4spd?
Good question.
  If it is an automatic, don't rule out the dipstick tube "O" ring. Way easier to fix.
Title: Re: GT500 tranny leaking
Post by: KR Convertible on June 25, 2026, 02:54:17 PM
I had a C4 that would occasionally leak a bunch of fluid, most of the time it wouldn't leak much.  Turned out to be a worn shift shaft.

I have also found that if you have to persuade the dipstick mounting tab to line up, it can cause the O-ring to leak.
Title: Re: GT500 tranny leaking
Post by: Drew Pojedinec on June 25, 2026, 07:08:56 PM
C6 when it sits can leak at dipstick o ring or servo lever plug inside the bellhousing.
The early style servo ball was the worst.
Title: Re: GT500 tranny leaking
Post by: KR500 on June 25, 2026, 08:53:33 PM
On C4 and C6 auto transmissions a leaking shift shaft seal is a very common problem
Title: Re: GT500 tranny leaking
Post by: roger on June 27, 2026, 01:55:04 PM
Another possible problem may be torque converter leak back. Especially if over filled. I know my 500 will leak a fair amount when it sits for a longer period of time, seems the transmission pan gets too full and out she comes around the side linkage! I solved my issue by running tranny with fluid down a bit. Falls into that category of " it worked for me "