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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: team39763 on November 08, 2008, 04:33:10 pm

Title: Can't seem to find the source of trans fluid leaks.
Post by: team39763 on November 08, 2008, 04:33:10 pm
I have a TH350 and the bottom is covered in fluid.  I noticed it before, but I thought it was from a vent or something and figured it'd stop when it got rid of excess fluid.  Well now almost a year later(about 60 miles on the trans), it's still leaking somewhere.  The bolts ont he bottom are tight, the gasket was a new cork type gasket.  The drain plug is also snug.  My speedo cable was disconnected and I figured that could account for some of the fluid...right?  But then there's fluid on the bottom of the ujoint behing the yoke, but none on the tailshaft.  I was pretty sure that my driveshaft is a bit short, so I wouldn't think it would have jabbed the trans.  I did put a good bit of extra fluid in the trans since I have a large cooler along with the stock cooler as well as a remote mounted trans filter(basically just a regular oil filter).  Is there somewhere that I should be looking?  I can't seem to find the source.
Title: Re: Can't seem to find the source of trans fluid leaks.
Post by: VileZambonie on November 09, 2008, 10:28:58 am
Clean it all off good and watch it. It won't vent unless it's running. If it drips just sitting there you should be able to trace where it's coming from. If not get some ATF UV dye and put it in there.
Title: Re: Can't seem to find the source of trans fluid leaks.
Post by: ccz145a on November 10, 2008, 05:10:14 pm
A lot of those rear yokes have a weep hole. I packed some white lithium grease in there on mine and slid it back on, seems to have stopped my leak from that location.
Title: Re: Can't seem to find the source of trans fluid leaks.
Post by: VeeTwin60 on November 30, 2008, 11:42:50 am
Have you checked where the trans dip-stick goes into the casting?  Sometimes the O-ring will deteriorate and leak.
Title: Re: Can't seem to find the source of trans fluid leaks.
Post by: grinder1989 on December 17, 2008, 02:03:24 am
I had a similar problem after I had my transmission rebuilt.  There is an O ring with the speedometer cable goes into the transmission and another where the kick down cable goes into the transmission.  I didn't have new ones because I had my transmission done at a shop where I just brought it in to them.  Put in the O rings and my transmission has never leaked a drop since.
Title: Re: Can't seem to find the source of trans fluid leaks.
Post by: team39763 on January 02, 2009, 11:40:02 am
The speedo cable was missing the o-ring(besides not being connected to the trans).  Some of the pan bolts were also loose.  I'll be correcting all that when I fix my converter this week.