My transmission leak...

R

Rob

Member
Nov 9, 2013
632
0
16
Johnny's posts prompted me to post about the transmission leak that I've been chasing for a while - it's been getting progressively worse over time...

I initially had a small leak from the speedometer drive - I didn't think that it was that bad, but I replaced the seal and O-ring and it seemed OK. It might still be dripping slowly...

I pulled the pan a few weeks ago and replaced an old cork gasket that appeared like it was weeping. I installed a WIX rubber pan gasket and also noticed my Ragusa pan had been painted in the past. The leak continues and may be getting slightly worse... Yesterday I tightened the chain cover bolts slightly - there was evidence of leakage there as well.

I've been having a very hard time getting it to leak in my sloped driveway - but today I covered the driver's side with baby powder and drove it back and forth for a while and eventually got a drop! The drops were on the transmission to final drive bolts - very near the dipstick. The dipstick area has always appeared reasonably dry.

I'll pull the dipstick and use RTV (per Jim K.'s previous posts - especially related to "you can waste a lot of time"). I've not seen any discussion regarding leakage from the governor cover or the bolts connecting to the final drive. So I'm thinking that the dipstick is still my main unknown (since I haven't pulled it yet)...

So - as long as the torque convertor is relatively full, how much trans fluid will come out of the dipstick tube when I pull it? Any other common leakage spots near that area (final drive mounting bolts near the dipstick)?

I've wasted a lot of time...

Rob
Victoria, BC
76 Royale - Rear Twins/Dry Bath
 
> Johnny's posts prompted me to post about the transmission leak that I've been chasing for a while - it's been getting progressively worse over
> time...
>
> I initially had a small leak from the speedometer drive - I didn't think that it was that bad, but I replaced the seal and O-ring and it seemed
> OK. It might still be dripping slowly...
>
> I pulled the pan a few weeks ago and replaced an old cork gasket that appeared like it was weeping. I installed a WIX rubber pan gasket and also
> noticed my Ragusa pan had been painted in the past. The leak continues and may be getting slightly worse... Yesterday I tightened the chain cover
> bolts slightly - there was evidence of leakage there as well.
>
> I've been having a very hard time getting it to leak in my sloped driveway - but today I covered the driver's side with baby powder and drove it
> back and forth for a while and eventually got a drop! The drops were on the transmission to final drive bolts - very near the dipstick. The dipstick
> area has always appeared reasonably dry.
>
> I'll pull the dipstick and use RTV (per Jim K.'s previous posts - especially related to "you can waste a lot of time"). I've not seen any
> discussion regarding leakage from the governor cover or the bolts connecting to the final drive. So I'm thinking that the dipstick is still my main
> unknown (since I haven't pulled it yet)...
>
> So - as long as the torque convertor is relatively full, how much trans fluid will come out of the dipstick tube when I pull it? Any other common
> leakage spots near that area (final drive mounting bolts near the dipstick)?
>
> I've wasted a lot of time...
>
> Rob
> Victoria, BC
> 76 Royale - Rear Twins/Dry Bath
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

l had some of the same wet symptoms. Chased them for a couple of years till I finally found the leak in a very unusual place. Check these pics.
Maybe...maybe not.

http://www.gmcmhphotos.com/photos/transmission-leak/p63991-odd-trans-leak.html

and

http://www.gmcmhphotos.com/photos/transmission-leak/p64051-img-1140.html

and

http://www.gmcmhphotos.com/photos/transmission-leak/p63994-odd-trans-leak.html
--
Larry
78 Royale w/500 Caddy
Menomonie, WI.
 
I don't think ANY fluid will leak out when you remove the dipstick tube. My recollection is that it is well above the fluid level. a well fitting
O-ring should fix the leak if it is coming from there. I guess it won't hurt to back it up with some RTV, but it should not be necessary.
--
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
 
Thanks for that.

I've never seen any fluid coming from the base of the dipstick tube - but the drips I witnessed today were very close to that spot (but appear to be coming from higher up than where the dipstick tube enters the case). I figured - it can't hurt to seal it up better. I just want it to slow down!

After 20 min of driving, the pan is wet. You'd think I'd be able to pinpoint the source, but so far - no luck... I've got more powder in that area now - so I'll try to get it to drip again tomorrow.

Rob
Victoria, BC
76 Royale - Rear Twins/Dry Bath

>
> I don't think ANY fluid will leak out when you remove the dipstick tube. My recollection is that it is well above the fluid level. a well fitting
> O-ring should fix the leak if it is coming from there. I guess it won't hurt to back it up with some RTV, but it should not be necessary.
> --
> 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
 
Thanks - I've looked at your pictures early on, but I can't see any sign of leaking up there!

Rob
Victoria, BC
76 Royale - Rear Twins/Dry Bath

>
> l had some of the same wet symptoms. Chased them for a couple of years till I finally found the leak in a very unusual place. Check these pics.
> Maybe...maybe not.
>
> http://www.gmcmhphotos.com/photos/transmission-leak/p63991-odd-trans-leak.html
>
> and
>
> http://www.gmcmhphotos.com/photos/transmission-leak/p64051-img-1140.html
>
> and
>
> http://www.gmcmhphotos.com/photos/transmission-leak/p63994-odd-trans-leak.html
> --
> Larry
> 78 Royale w/500 Caddy
> Menomonie, WI.
 
Look at the trans from the top a there are times when you'll see some leaks.
Keep in mind that the dip tube will leak more when it sits for few days as
the convertor will bleed down and flood the trans.
I have neer seen the leak at the gov.

> Thanks - I've looked at your pictures early on, but I can't see any sign
> of leaking up there!
>
> Rob
> Victoria, BC
> 76 Royale - Rear Twins/Dry Bath
>

> >
> > l had some of the same wet symptoms. Chased them for a couple of years
> till I finally found the leak in a very unusual place. Check these pics.
> > Maybe...maybe not.
> >
> > http://www.gmcmhphotos.com/photos/transmission-leak/
> p63991-odd-trans-leak.html
> >
> > and
> >
> > http://www.gmcmhphotos.com/photos/transmission-leak/p64051-img-1140.html
> >
> > and
> >
> > http://www.gmcmhphotos.com/photos/transmission-leak/
> p63994-odd-trans-leak.html
> > --
> > Larry
> > 78 Royale w/500 Caddy
> > Menomonie, WI.
> _______________________________________________
> 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
 
Instead of an "o"ring to seal you can try this grommet.

https://www.napaonline.com/en/p/NDP7355004

Coat the grommet with a sealant under the lip and coat the dipstick tube
with sealant around the stop on dipstick tube.

On Wed, Jun 20, 2018 at 10:56 PM, Armand Minnie
wrote:

> There is a weep hole that is right next to the dipstick tube. If the seal
> between the final drive and the transmission is leaking it will come out of
> that hole. Happened to me.
> --
> Armand Minnie
> Marana, AZ
> '76 Eleganza II TZE166V103202
> http://www.minniebiz.com
> http://www.gmcws.org
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class
 
Thanks.

It seems to only be leaking when “moving” - I’ve had a hard time getting it to leak when I can see where it might be coming from. It does seem lower than the governor cover.

I’m still suspicious of the dipstick to case seal - but it always looks fairly dry there.

I’m hoping I can make it drip again today in my “controlled” environment...

Rob
Victoria, BC
76 Royale - Rear Twins/Dry Bath

>
> Look at the trans from the top a there are times when you'll see some leaks.
> Keep in mind that the dip tube will leak more when it sits for few days as
> the convertor will bleed down and flood the trans.
> I have neer seen the leak at the gov.
> --
> Jim Kanomata
> Applied/GMC, Newark,CA
> jimk
> http://www.appliedgmc.com
> 1-800-752-7502
 
Thanks. Yes - I’ve been watching the weep hole for a while and have never seen anything emerge from there (I thought that I should have mentioned watching it, shortly after I sent my original post). I think that’s good news - hopefully means that seal is OK...

The source seems higher than the weep hole...

Rob
Victoria, BC
76 Royale - Rear Twins/Dry Bath

>
> There is a weep hole that is right next to the dipstick tube. If the seal between the final drive and the transmission is leaking it will come out of
> that hole. Happened to me.
> --
> Armand Minnie
> Marana, AZ
> '76 Eleganza II TZE166V103202
> http://www.minniebiz.com
> http://www.gmcws.org
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
Thanks - I’ll see if I can find that part!

Rob
Victoria, BC
76 Royale - Rear Twins/Dry Bath

>
> Instead of an "o"ring to seal you can try this grommet.
>
> https://www.napaonline.com/en/p/NDP7355004
>
> Coat the grommet with a sealant under the lip and coat the dipstick tube
> with sealant around the stop on dipstick tube.
>
> --
> Bruce Hart
> 1976 Palm Beach
> Milliken, Co
> GMC=Got More Class
 
> Instead of an "o"ring to seal you can try this grommet.
>
> https://www.napaonline.com/en/p/NDP7355004
>
> Coat the grommet with a sealant under the lip and coat the dipstick tube
> with sealant around the stop on dipstick tube.

I looked at the seal on the NAPA site. I can not figure out how it would be used to replace the O-ring. I guess I would have to order one and see it
for my self .
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
I was able to get the leak to occur again this morning - it does not appear to be from where the dipstick enters the case OR the nearby weep hole.

It appears to be originating from the area around the upper bolt (transmission to final housing), just below the governor and towards the front (from the base of the speedometer drive port). I can't see any fluid from above the bolts (which would be below the governor housing?). But it's very hard to see in that area - I've tried with a light and mirror, but don't see much.

This link is a pic of the area:

https://photos.app.goo.gl/JpHZN7dmvUxVUaDe7

This pic has the bolt circled where I first see the fluid and a line showing the path the fluid takes to head down and out:

https://photos.app.goo.gl/cDBgDvPtKs7ykm2X9

Does the upper bolt have fluid behind it? Does the governor housing have a seal at the base of it - near the case (or is that just one casting)?

I actually tried to contact Manny last week - but I was told he's on a cruise! Good for him - that might be my next step... But I've got a GMC trip in less than a week and I'd love to slow this down...

Thanks in advance for any input...

Rob
Victoria, BC
76 Royale - Rear Twins/Dry Bath

>
> Johnny's posts prompted me to post about the transmission leak that I've been chasing for a while - it's been getting progressively worse over time...
>
> I initially had a small leak from the speedometer drive - I didn't think that it was that bad, but I replaced the seal and O-ring and it seemed OK. It might still be dripping slowly...
>
> I pulled the pan a few weeks ago and replaced an old cork gasket that appeared like it was weeping. I installed a WIX rubber pan gasket and also noticed my Ragusa pan had been painted in the past. The leak continues and may be getting slightly worse... Yesterday I tightened the chain cover bolts slightly - there was evidence of leakage there as well.
>
> I've been having a very hard time getting it to leak in my sloped driveway - but today I covered the driver's side with baby powder and drove it back and forth for a while and eventually got a drop! The drops were on the transmission to final drive bolts - very near the dipstick. The dipstick area has always appeared reasonably dry.
>
> I'll pull the dipstick and use RTV (per Jim K.'s previous posts - especially related to "you can waste a lot of time"). I've not seen any discussion regarding leakage from the governor cover or the bolts connecting to the final drive. So I'm thinking that the dipstick is still my main unknown (since I haven't pulled it yet)...
>
> So - as long as the torque convertor is relatively full, how much trans fluid will come out of the dipstick tube when I pull it? Any other common leakage spots near that area (final drive mounting bolts near the dipstick)?
>
> I've wasted a lot of time...
>
> Rob
> Victoria, BC
> 76 Royale - Rear Twins/Dry Bath
 
Rob,

Is it an optical illusion, my OLD eyes, or an actual crack in your case,
basically along the red line in your second photo?

Ken H.

> I was able to get the leak to occur again this morning - it does not
> appear to be from where the dipstick enters the case OR the nearby weep
> hole.
>
> It appears to be originating from the area around the upper bolt
> (transmission to final housing), just below the governor and towards the
> front (from the base of the speedometer drive port). I can't see any fluid
> from above the bolts (which would be below the governor housing?). But it's
> very hard to see in that area - I've tried with a light and mirror, but
> don't see much.
>
> This link is a pic of the area:
>
> https://photos.app.goo.gl/JpHZN7dmvUxVUaDe7
>
> This pic has the bolt circled where I first see the fluid and a line
> showing the path the fluid takes to head down and out:
>
> https://photos.app.goo.gl/cDBgDvPtKs7ykm2X9
>
> Does the upper bolt have fluid behind it? Does the governor housing have a
> seal at the base of it - near the case (or is that just one casting)?
>
> I actually tried to contact Manny last week - but I was told he's on a
> cruise! Good for him - that might be my next step... But I've got a GMC
> trip in less than a week and I'd love to slow this down...
>
> Thanks in advance for any input...
>
> Rob
> Victoria, BC
> 76 Royale - Rear Twins/Dry Bath
>

> >
> > Johnny's posts prompted me to post about the transmission leak that I've
> been chasing for a while - it's been getting progressively worse over
> time...
> >
> > I initially had a small leak from the speedometer drive - I didn't think
> that it was that bad, but I replaced the seal and O-ring and it seemed OK.
> It might still be dripping slowly...
> >
> > I pulled the pan a few weeks ago and replaced an old cork gasket that
> appeared like it was weeping. I installed a WIX rubber pan gasket and also
> noticed my Ragusa pan had been painted in the past. The leak continues and
> may be getting slightly worse... Yesterday I tightened the chain cover
> bolts slightly - there was evidence of leakage there as well.
> >
> > I've been having a very hard time getting it to leak in my sloped
> driveway - but today I covered the driver's side with baby powder and drove
> it back and forth for a while and eventually got a drop! The drops were on
> the transmission to final drive bolts - very near the dipstick. The
> dipstick area has always appeared reasonably dry.
> >
> > I'll pull the dipstick and use RTV (per Jim K.'s previous posts -
> especially related to "you can waste a lot of time"). I've not seen any
> discussion regarding leakage from the governor cover or the bolts
> connecting to the final drive. So I'm thinking that the dipstick is still
> my main unknown (since I haven't pulled it yet)...
> >
> > So - as long as the torque convertor is relatively full, how much trans
> fluid will come out of the dipstick tube when I pull it? Any other common
> leakage spots near that area (final drive mounting bolts near the dipstick)?
> >
> > I've wasted a lot of time...
> >
> > Rob
> > Victoria, BC
> > 76 Royale - Rear Twins/Dry Bath
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
To my a bit younger eyes, that looks to be a crack as Ken said. Any way to spray that area with brake cleaner and a hit it with a wire brush? That
would at least clean it up more for a better inspection. There may be a lot of crud sticking to that area. If it is indeed cracked, I wonder if
putting some JB weld in there may stop it up better until you can properly address it.
--
77 Royale, Rear Dry Bath. 403, 3.55 Final Drive, Lenzi goodies, Patterson carb and dizzy.
Mid Michigan
 
It may be a crack - but it may also just be the "line" that the ATF is creating in all the baby powder in that area! Now that I know the area of the leak - I'll clean it up and look for a crack.

I've been reading the Maintenance Manual and studying pics in the transmission chapter. I think the bolt that is the first place I see fluid is BOLT "A", it then runs down the case towards BOLT "B" and BOLT "E".

The manual mentions soaking the gasket between the trans and final drive in ATF before assembly - so I'm assuming there is some ATF on both sides of the gasket. Last night I put a short socket drive on "B" and "E" and they weren't loose...

Rob
Victoria, BC
76 Royale - Rear Twins/Dry Bath

>
> Rob,
>
> Is it an optical illusion, my OLD eyes, or an actual crack in your case,
> basically along the red line in your second photo?
>
> Ken H.
 
I don't think there is a crack, here's a pic after being cleaned up:

https://photos.app.goo.gl/mmxXnEbFNh75LkgBA

I put a wrench on BOLT "A" and it was tight, but not very. Manual said 25 ft-lbs - this may have been 10? I couldn't easily get a socket on there - so it's now "tight is tight enough".

I'll try to get it out for a test run and see if it's any better. But I've kind of used up the majority of my optimism on my previous attempts...

Rob
Victoria, BC
76 Royale - Rear Twins/Dry Bath

>
> It may be a crack - but it may also just be the "line" that the ATF is creating in all the baby powder in that area! Now that I know the area of the leak - I'll clean it up and look for a crack.
>
> I've been reading the Maintenance Manual and studying pics in the transmission chapter. I think the bolt that is the first place I see fluid is BOLT "A", it then runs down the case towards BOLT "B" and BOLT "E".
>
> The manual mentions soaking the gasket between the trans and final drive in ATF before assembly - so I'm assuming there is some ATF on both sides of the gasket. Last night I put a short socket drive on "B" and "E" and they weren't loose...
>
> Rob
> Victoria, BC
> 76 Royale - Rear Twins/Dry Bath
 
Thanks for the reply - this is a cleaned up pic:

https://photos.app.goo.gl/mmxXnEbFNh75LkgBA https://photos.app.goo.gl/mmxXnEbFNh75LkgBA

I think the case is OK. Just way too much baby powder! But it helped the process...

Rob
Victoria, BC
76 Royale - Rear Twins/Dry Bath

>
> To my a bit younger eyes, that looks to be a crack as Ken said. Any way to spray that area with brake cleaner and a hit it with a wire brush? That
> would at least clean it up more for a better inspection. There may be a lot of crud sticking to that area. If it is indeed cracked, I wonder if
> putting some JB weld in there may stop it up better until you can properly address it.
> --
> 77 Royale, Rear Dry Bath. 403, 3.55 Final Drive, Lenzi goodies, Patterson carb and dizzy.
> Mid Michigan
 
Agree, cleaned up pic doesn't appear to show any cracks. Thats a good thing. Smarter people will chime in, but I wonder if backing out that top
bolt holding the dip stick tube and putting a little dab of RTV at the top where it will eventually snug back down would help. Perhaps even on the
last few threads before the bolt head. (not loctite).
--
77 Royale, Rear Dry Bath. 403, 3.55 Final Drive, Lenzi goodies, Patterson carb and dizzy.
Mid Michigan
 
Rob,

Comparing an enlarged view of your photo with the FD in my coach, and the
two un-installed ones here, I don't see how that can be anything other than
a crack -- and the source of your leak. You should be able to test that
hypothesis easily with a fine wire -- probably even a small straightened
paper clip -- it will probably slide right into that "crack".

It's hard to believe anyone could be hamfisted enough to break that FD
case, but if the FD was misaligned when attaching it to the TH-425, it
would certainly be possible. I'd be surprised that the transmission wasn't
damaged also, but stranger things have happened.

If it IS a crack, the possibility of filling it with RTV or epoxy as a
stop-gap measure may work, but I certainly would want to get the thing
apart to check for obvious transmission/case damage and to replace that FD
(or at least the case).

Ken "Hoping I'm Wrong" H.

> I don't think there is a crack, here's a pic after being cleaned up:
>
> https://photos.app.goo.gl/mmxXnEbFNh75LkgBA
>
> I put a wrench on BOLT "A" and it was tight, but not very. Manual said 25
> ft-lbs - this may have been 10? I couldn't easily get a socket on there -
> so it's now "tight is tight enough".
>
> I'll try to get it out for a test run and see if it's any better. But I've
> kind of used up the majority of my optimism on my previous attempts...
>
>
 
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