Home page

Topic: Suburban A/T leaking around the pan

in Forum: Non-Vette Automotive Discussion

Back to top of thread


Already a Member?
Login
Not yet a Member?
Register for Free!

Re: Suburban A/T leaking around the pan (3/13)
 7/6/15 7:20am
Adams' AppleLifetime Member
Lifetime Member
Moderator
Send Private Message

Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


Joined: 11/8/2003
Posts: 19904

Need to first determine if it IS the pan leaking. Check the selector(shifter linkage) shaft that sticks out of the ds of the trans, the filler tube seal, cooler lines, and the electrical connector....all of these places can leak, and seep around the pan, making it appear to be a pan gasket leak.
What type of gasket did you use? Cork, "farpack", black paper?


______________
Joel Adams
C3VR Lifetime Member #56    

My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Re: Suburban A/T leaking around the pan (4/13)
 7/7/15 2:22am
daveo76
Standard Member
Send Private Message

Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.


Joined: 8/25/2005
Posts: 857

Thanks guys.  Joel, I double checked the stuff you mentioned and I'm 95% sure it's the pan gasket.  Entire driver's side is pretty dry - electrical connector and selector are dry.  On the passenger side there are the oil cooler lines (totally dry) and the dipstick/filler tube.  It could be the filler tube, but it does not look like it.  Worst case seeping is at front and back of tranny.  In fact, most is going on to the t-case skid plate and dripping through a hole in that.  At the front, it is dripping down the bell housing and falling off at it's low point.  The seeping is between the pan and the gasket, not the gasket and the tranny case which kind of tells me it is not coming from above?  

Not sure what material the gasket is.  Definitely not cork, pretty sure it's not paper.  What is farpack?  It's black and somewhat rigid.  Suggestions on what to use next time?  

I'm thinking another pan drop will be required.  I'm hoping to re-use the fluid - it's brand new and there are 6-7 quarts in there.  I'll use very clean containers.  The PO did one thing right and installed a drain plug in the pan - at least that makes things a little easier.  John, I inspected the sealing edge of the pan last time, but did not check it with a straight edge - lesson learned.  


______________

 

1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
Re: Suburban A/T leaking around the pan (5/13)
 7/7/15 12:03pm
Vman73
Former Member

Send Private Message

Gig Harbor, WA - USA

Vette(s):
1973 L82 4 Speed Coupe - Very original, well documented driver/survivor. 2016 Bend Regional NCRS Top Flight.


Joined: 10/2/2014
Posts: 405

Dave, not super familiar with '91 suburban tranny, but if it is a stamped steel pan, did you tap back the mounting holes with a ball peen hammer ??

______________
John Sigmund
valkman57@sbcglobal.net
NCRS Member 61302
NW NCRS Chapter Member



Duct tape is the new Black !!
Re: Suburban A/T leaking around the pan (6/13)
 7/7/15 12:54pm
Adams' AppleLifetime Member
Lifetime Member
Moderator
Send Private Message

Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


Joined: 11/8/2003
Posts: 19904

Sounds like a reusable gasket, Dave. Not many problems with those at all. Could have a buggered up spot on the pan somewhere I suppose....What of gasket did it have on it when you removed it the first time?

 



______________
Joel Adams
C3VR Lifetime Member #56    

My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Re: Suburban A/T leaking around the pan (7/13)
 7/8/15 10:52pm
daveo76
Standard Member
Send Private Message

Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.


Joined: 8/25/2005
Posts: 857

Joel, I don't think it's a reusable one - it didn't have that bead of rubber or silicone or whatever.  But I did just order an ATP reusable from Amazon.  Guess what I'm doing this weekend???

Thanks!




______________

 

1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
Re: Suburban A/T leaking around the pan (8/13)
 7/9/15 12:58pm
Adams' AppleLifetime Member
Lifetime Member
Moderator
Send Private Message

Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


Joined: 11/8/2003
Posts: 19904

Most of the factory, and aftermarket reusable gaskets don't have the red/orange bead of rubber...most are all black. That just happened to be the pic I had. Reusable gaskets for the 4L80 are stiff. Actually rubber coated steel.
Cork gaskets are of course flimsy, and the Farpack gaskets are kinda in between...not stiff, but not floppy.
The pan rail itself doesn't have to be perfect....the gasket will fill in any minor defects. If the pan has any bent spots, or large dings, then you'll need to flatten it out as best you can. Check the surface of the trans well, too, for any gouges, or leftover gasket pieces.
You could get a later model(deeper) pan, and deep filter for it, too. The late/deep pans are made a little better(thicker steel), and have fewer issues with leakage. Thumbs Up


______________
Joel Adams
C3VR Lifetime Member #56    

My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Re: Suburban A/T leaking around the pan (9/13)
 7/12/15 1:58am
daveo76
Standard Member
Send Private Message

Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.


Joined: 8/25/2005
Posts: 857

I got the ATP reusable pan gasket today - no instructions.  Assuming it goes on totally dry?  

So on a different note but same subject: the burb has not moved or run for over a week now and it's still dripping and seeping.  How can that be?  Did I really overfill it?  It was less than a 1/4" past full on the dipstick after I ran it in stop and go traffic on a hot day.  Maybe the dipstick is not seating properly and I'm putting enough in that the cold, static level is higher than the top of the pan?  Last time I drove it tranny was acting normal and shifting just fine.  


______________

 

1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
Re: Suburban A/T leaking around the pan (10/13)
 7/12/15 10:20am
Adams' AppleLifetime Member
Lifetime Member
Moderator
Send Private Message

Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


Joined: 11/8/2003
Posts: 19904

ALL gaskets should be installed dry, with very few exceptions....imho. The re-usable gaskets can be installed with fluid on them, and they will still not leak, so they don't have to be perfectly dry when changing fluid, tho it is better to be clean & dry.

I'm bettin your leak/seep is something other than the pan, Dave, unless your pan is messed up. 1/4" overfull won't hurt anything, but it certainly can cause the fluid to spew out of the vent when it gets hot. Trans fluid expands as it gets hot, which is why there is a "Cold" and "Hot" marking on the dipping stick. Hot fluid should be in the middle, between the cold and hot limits. A little over is fine, as far as operating functions go.

My only suggestion is to use some brake cleaner, and spray the whole thing off...get it nice and clean. Drive it, let it sit overnight, and look for seepage/trails.



______________
Joel Adams
C3VR Lifetime Member #56    

My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Re: Suburban A/T leaking around the pan (11/13)
 7/14/15 2:27am
daveo76
Standard Member
Send Private Message

Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.


Joined: 8/25/2005
Posts: 857

Well I drained and dropped the pan tonight.  Inspected the gasket I put in a few weeks ago - it's a flexible, black material, kind of like hard rubber, very thin.  (not much thicker than the rubber of a bicycle tire tube).  Inspected the pan and found a low spot on the bolting rim that is (what a surprise) right where I was seeing most of the seeping.  I lightly ball peened the rim in that area and got it to look a little better with a straight edge.  lightly peened some of the bolt holes that were slightly mushroomed, too.  Then installed pan with my new, reusable, much thicker, ATP gasket.  Also, the holes have grommets - on the old gasket the bolts fit in the holes very tight, I'm wondering if that could be some of my problem, too.  (gasket twisted a little as I was tightening bolts??)  Anyway, tomorrow I will fill it and test drive and hope for the best!  Thanks for the help.  

______________

 

1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
Re: Suburban A/T leaking around the pan (12/13)
 7/14/15 7:17am
Adams' AppleLifetime Member
Lifetime Member
Moderator
Send Private Message

Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


Joined: 11/8/2003
Posts: 19904

Ah yes....the cheesy inner tube gasket...LOL  Never seen one of those things actually work...too thin, and mooshy to seal anything. Add in a slightly disfigured pan surface, and you have a recipe for leakage.
The new gasket should fix it up nicely. Thumbs Up 

______________
Joel Adams
C3VR Lifetime Member #56    

My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Re: Suburban A/T leaking around the pan (13/13)
 7/16/15 1:47am
daveo76
Standard Member
Send Private Message

Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.


Joined: 8/25/2005
Posts: 857

Go things put back together last night and drove it to work today - Knock on wood ....no seeping yet.  Time will tell.  Thanks again for the help.  

______________

 

1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
Our Sponsors help support C3VR