Transmission Leak

T

tom geiger

New member
Dec 31, 2006
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A little update on the shifting issue I had. Had replaced the modulator and it did not seem to improve the shifting up and down from 3rd to 2nd so I
took it into the truck and RV service center near me and had a transmission service done to it and now everything is back to normal, so it had to
have been an issue with filter or level of fluid as well. It is a bit difficult to get a good reading on fluid level on this thing. Anyhow, glad it
is back to shifting smoothly. I did notice that the transmission pan seems to be leaking a whole bunch more. Leaves a good square spot on the
driveway. Is this something this is typical when a service is done, or did my service place muck something up?

Tom
76 Eleganza 2
Kansas City, Mo
 
Perhaps they used an air impact on the pan bolts and dimpled the pan at each bolt hole. That reduces clamping on areas between bolt holes. You have
to remove and set upside down on flat hard surface to see. Then carefully hammer the dimples back till granite smooth. Torque specs are important.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
Have seen about a 1/2 dozen pans come loose in my life time after some mechanic had the pan off. I can't blame the mechanic as one of those was a
tranny pan inhad off myself. The bolts torque is low and i think the gasket and heat cycles can make the bolts come loose.

So i always check transmission pan bolts a few times after they have been removed and replaced now.

However the other problem our old coaches have is torque converter leak down. When parked the fluid leaks out of the torque converter and over fills
the pan, causing it to leave a mark on ground when parked.

--
Jon Roche
75 palm beach
St. Cloud, MN
http://lqqkatjon.blogspot.com/
 
Ok guys, will check on those items. Is there any special extra thick gasket that would seal things up better like we had for my Thorley headers I got
from Jim K? Or is the stock gasket out of the service kit all we have?
 
Curious to know if anyone has had better sealing luck with the cork or rubberized gaskets?
--
77 Royale, Rear Dry Bath. 403, 3.55 Final Drive, Lenzi goodies, Patterson carb and dizzy.
Mid Michigan
 
Keep in mind some of the transmission bolts protrude into the fluid so they can leak around the bolt. In this case it would help to use a bolt with a
built in washer and a little gasket with sealer. Just look real close at each bolt to see if it is the source of a leak.
--
Roy Keen
Minden,NV
76 X Glenbrook
 
I do not know of a thicker pan gasket.
Just straighten the pan lip by using a ball pene hammer.
Also a cast Aluminum pan can help seal better,

> Keep in mind some of the transmission bolts protrude into the fluid so
> they can leak around the bolt. In this case it would help to use a bolt
> with a
> built in washer and a little gasket with sealer. Just look real close at
> each bolt to see if it is the source of a leak.
> --
> Roy Keen
> Minden,NV
> 76 X Glenbrook
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
Tom,

Suggest you:

- remove the pan and check the flange to see if there are dings around the bolt holes

- remove them with a two ball peen hammers - put one in the bolt hole and hit the flat face with the other

- replace the cork gasket - cork is OK

- replace the bolts with self locking flange bolts http://tinyurl.com/y99jnfgk

- coat the pan flange with Permatex Aviation Form-A-Gasket No. 3 Sealant http://tinyurl.com/y7zmy4rw

- put the cork gasket on the pan flange and coat it with Permatex Aviation Form-A-Gasket No. 3 Sealant

- install the pan on the transmission case and hand tighten the bolts lightly

- torque the bolts to 12 ft lb

- service the transmission

- go for a test drive

- have a beer when you get home to celebrate fixing the problem

Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808


-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of tom geiger
Sent: Tuesday, August 29, 2017 11:03 PM
To: gmclist
Subject: [GMCnet] Transmission Leak

A little update on the shifting issue I had. Had replaced the modulator and it did not seem to improve the shifting up and down
from 3rd to 2nd so I
took it into the truck and RV service center near me and had a transmission service done to it and now everything is back to normal,
so it had to
have been an issue with filter or level of fluid as well. It is a bit difficult to get a good reading on fluid level on this thing.
Anyhow, glad it
is back to shifting smoothly. I did notice that the transmission pan seems to be leaking a whole bunch more. Leaves a good square
spot on the
driveway. Is this something this is typical when a service is done, or did my service place muck something up?

Tom
76 Eleganza 2
Kansas City, Mo

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Ah, well there is my problem Rob. My sequence of events is backwards when I do work on Sugar Pie. I start with the beer and then go on to the next
steps!
 
Nothing wrong with that as long as you don't wind up looking through beer goggles! ;-)

Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of tom geiger
Sent: Wednesday, August 30, 2017 10:04 AM
To: gmclist
Subject: Re: [GMCnet] Transmission Leak

Ah, well there is my problem Rob. My sequence of events is backwards when I do work on Sugar Pie. I start with the beer and then go
on to the next
steps!

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GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
In some cases, if the pan bolts are over tightened, the gasket can squeeze out (or in, which is harder to see) causing a leak. I had this happen with
a Gary Rockwell pan that I never could get to seal right. When I traded it in to Jim K for a Ragussa pan, he sent me a FelPro gasket that had the
perfect size holes in it, and sealed really well.

I recently did this job again, and used the gasket that came in the filter kit (also from Jim K. and it sealed perfectly as well. I prefer to not use
any type of gasket sealer if I can get away with it, due to the clean-up issues the next time. I did follow the manual torque spec of 12 foot pounds
and it is nie and tight with no leaks.
--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles,
Solar battery charging. GMCSJ and GMCMI member
 
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