Needle in a haystack...
Thread Starter
1972 U code Supreme
Joined: Jul 2018
Posts: 4,100
From: Chesapeake, VA
Needle in a haystack...
Greetings to all ye Oldsmobilers!
While returning from the Endless Summer Cruise today I noticed my Turbo 400 has developed a leak. From what I can tell, the fluid is "collecting" along the floorboard under the passenger side seat and splashing onto the passenger side exhaist.
I don't see any fluid on the underside where the foot panel is so I'm thinking it's coming from the passenger side of the transmission somewhere. My 72 Cutlass Supreme does have a tranny fluid cooler and as of now she upshifts and downshifts fine.
Also, I don't feel any slipping whether I'm under acceleration or on an incline, and I don't see any fluid around the pan seal. I did add a quart before I left to come home so is it possible I overfilled? I did check my dipstick really good before I added the quart and it looked low. After I added the quart it looked good.
Can anyone give me some direction where to look for this "needle in a haystack?"
Thanks,
Dave
While returning from the Endless Summer Cruise today I noticed my Turbo 400 has developed a leak. From what I can tell, the fluid is "collecting" along the floorboard under the passenger side seat and splashing onto the passenger side exhaist.
I don't see any fluid on the underside where the foot panel is so I'm thinking it's coming from the passenger side of the transmission somewhere. My 72 Cutlass Supreme does have a tranny fluid cooler and as of now she upshifts and downshifts fine.
Also, I don't feel any slipping whether I'm under acceleration or on an incline, and I don't see any fluid around the pan seal. I did add a quart before I left to come home so is it possible I overfilled? I did check my dipstick really good before I added the quart and it looked low. After I added the quart it looked good.
Can anyone give me some direction where to look for this "needle in a haystack?"
Thanks,
Dave
Last edited by 72455; Oct 12, 2018 at 04:17 PM.
Registered User
Joined: Feb 2013
Posts: 15,409
From: Phoenix, AZ
Clean the floorboards and trans, drive a bit, then look for the trans fluid. That should tell you where the leak is.
There aren't a whole lot of things on the drivers side of the transmission that can leak. Most things are on the passengers side (cooling lines, vacuum modulator, dipstick, etc).
There aren't a whole lot of things on the drivers side of the transmission that can leak. Most things are on the passengers side (cooling lines, vacuum modulator, dipstick, etc).
Thread Starter
1972 U code Supreme
Joined: Jul 2018
Posts: 4,100
From: Chesapeake, VA
Clean the floorboards and trans, drive a bit, then look for the trans fluid. That should tell you where the leak is.
There aren't a whole lot of things on the drivers side of the transmission that can leak. Most things are on the passengers side (cooling lines, vacuum modulator, dipstick, etc).
There aren't a whole lot of things on the drivers side of the transmission that can leak. Most things are on the passengers side (cooling lines, vacuum modulator, dipstick, etc).
Registered User
Joined: Jun 2009
Posts: 15,194
From: southeastern Michigan
You haven't told is the full story here. HOW did you check the transmission fluid? Not cold, I hope. You're supposed to check it with the engine and transmission fully warmed up and the engine running and in Park when you remove the dipstick. If you checked it cold with the engine off, then, yes, it would likely look to be low, and if you added a quart on the basis of this, you could easily have overfilled it. This could result in fluid being pushed out the top of the dipstick tube and running down the side of the tube onto the transmission once it warms up and you're cruising down the highway.
Thread Starter
1972 U code Supreme
Joined: Jul 2018
Posts: 4,100
From: Chesapeake, VA
You haven't told is the full story here. HOW did you check the transmission fluid? Not cold, I hope. You're supposed to check it with the engine and transmission fully warmed up and the engine running and in Park when you remove the dipstick. If you checked it cold with the engine off, then, yes, it would likely look to be low, and if you added a quart on the basis of this, you could easily have overfilled it. This could result in fluid being pushed out the top of the dipstick tube and running down the side of the tube onto the transmission once it warms up and you're cruising down the highway.
Registered User
Joined: Jan 2010
Posts: 6,105
From: central Indiana
The vent is on the passenger side of the case, around the 11 O’clock position of your looking from the front of the car. That’s about the only place fluid could come from a elevated area. Other possible leak points are the vacuum modulator o-ring, the dipstick tube, pan gasket, or around the pump. If the trans is overfilled my guess would be for the vent. Get it up to operating temp, idling in park and on level ground. If it’s over full drain some out.
Thread Starter
1972 U code Supreme
Joined: Jul 2018
Posts: 4,100
From: Chesapeake, VA
Started it up today and let in run for about 30 min or so. Checked the fluid and it was low. Added half a quart and that topped it off. I checked for leaks and didn't see any fluid. No leaks in the driveway and I checked for leaks once it was warmed up but didn't see where it's coming from...thoughts?
Registered User
Joined: Feb 2010
Posts: 1,585
From: Modesto CA
Did your car sit for awhile before it developed the leak? If so the torque converter will drain back into the pan causing it to be over full (why you need to check fluid level at operating temperature). This will often cause intermittent leaks on things that wouldn’t normally leak. In my case it was the kick down cable(Th350). The housing was cracked and when the torque converter would drain, fluid levels would rise and the leak would present.
Registered User
Joined: Jan 2010
Posts: 6,105
From: central Indiana
Of you can’t determine for sure where it’s leaking from, get some A/C oil with fluorescent dye and pour a little in the trans fluid. Run the trans for a while, then look with a black light. The dye will highlight exactly where the leak is coming from
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