Transmission filter change, how much fluid will I need?

RF_Burns

RF_Burns

Super Moderator
Staff member
Sep 7, 2008
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Ontario Canada
I've search around and I know it should be on here somewhere, but I haven't been able to find it.

Can anyone tell me how much transmission fluid I'll need when changing a transmission filter? I'll be fixing the leak in shifter shaft at the same
time so I'll have the pan open for several hours if that makes any difference.

Thanks.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
 
> I've search around and I know it should be on here somewhere, but I haven't been able to find it.
>
> Can anyone tell me how much transmission fluid I'll need when changing a transmission filter? I'll be fixing the leak in shifter shaft at the
> same time so I'll have the pan open for several hours if that makes any difference.
>
> Thanks.

Bruce,
If the trans has been shut down for a couple of hours, it won't drain down much more, but it will store 5~6 quarts mostly in the torque converter.
So, if you take the pan down, expect a minimum of four and maybe as much as six. When I last changed a filter, I had four on hand, but it ended up
needed a couple more.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
It depends on each case.
Dump in 4 and run engine for couple min and see.
Fill only to Add line as trans is cold.

On Sat, May 25, 2019 at 8:48 AM Bruce Hislop via Gmclist <

> Matt,
> Forgot I also have a Ragusa transmission pan, so that holds a bit more. So
> I best get 8 litres to be safe.
>
> Thanks
>
> --
> Bruce Hislop
> ON Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> My Staff says I never listen to them, or something like that
>
> _______________________________________________
> 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
 
Sam, my transmission go to guy, says "If your transmission shows full on
the stick, then, capture the drained fluid, measure what you drain, and
return that much to the transmission when you refill it..
Jim Hupy

On Sat, May 25, 2019 at 8:48 AM Bruce Hislop via Gmclist <

> Matt,
> Forgot I also have a Ragusa transmission pan, so that holds a bit more. So
> I best get 8 litres to be safe.
>
> Thanks
>
> --
> Bruce Hislop
> ON Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> My Staff says I never listen to them, or something like that
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
> I've search around and I know it should be on here somewhere, but I haven't been able to find it.
>
> Can anyone tell me how much transmission fluid I'll need when changing a transmission filter? I'll be fixing the leak in shifter shaft at the same
> time so I'll have the pan open for several hours if that makes any difference.
>
> Thanks.
>
Bruce

How bad of a leak did you have with the shifter shaft seal?  Mine is
leaking, a lot. I was wondering if it could be this seal, or is
something else leaking also. I lost 4 quarts in 200 miles.

Matt

I the trans fluid under pressure at the shift shaft seal?  Could I be
loosing that much oil there?

--
Gary W. Mills
Livonia, MI
. ___________
./_][__][] []| 1974 GMC M/H
.*O-------OO-* Painted Desert
 
> Bruce
>
> How bad of a leak did you have with the shifter shaft seal?  Mine is
> leaking, a lot. I was wondering if it could be this seal, or is
> something else leaking also. I lost 4 quarts in 200 miles.
>
> Matt
>
> I the trans fluid under pressure at the shift shaft seal?  Could I be
> loosing that much oil there?
>
> --
> Gary W. Mills
> Livonia, MI

Gary,

I haven't looked up in there in years, but as I recall, that shift control is in the outer space. That means that the only pressure on it should be
the same case pressure as the dipstick aka not much.
I would suggest that if it is leaking that much, you locate the leak before you do much else.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
If you have a remote dipstick, it is very possible that your transmission
is overfilled. If it is, you will blow fluid out of places that would
normally not leak if the level were correct.
Jim Hupy

On Sat, May 25, 2019, 12:06 PM Matt Colie via Gmclist <

> > Bruce
> >
> > How bad of a leak did you have with the shifter shaft seal? Mine is
> > leaking, a lot. I was wondering if it could be this seal, or is
> > something else leaking also. I lost 4 quarts in 200 miles.
> >
> > Matt
> >
> > I the trans fluid under pressure at the shift shaft seal? Could I be
> > loosing that much oil there?
> >
> > --
> > Gary W. Mills
> > Livonia, MI
>
> Gary,
>
> I haven't looked up in there in years, but as I recall, that shift control
> is in the outer space. That means that the only pressure on it should be
> the same case pressure as the dipstick aka not much.
> I would suggest that if it is leaking that much, you locate the leak
> before you do much else.
>
> Matt
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Electronically Controlled Quiet Engine Cooling Fan
> OE Rear Drum Brakes with Applied Control Arms
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Gary,
My shifter shaft always leaked a little bit, but when I moved it out of the shop for the day and then put it back, next day there was a couple of
tablespoons worth on the floor. Paula has taken over my entire shop with her furniture refinishing lately so for a few days I was moving it out every
morning and back inside in the evening. Now I just leave it outside.

However since taking it for a spin into town for gas, the leak seems to have slowed. I was able to put it back in today due to severe storms passing
through. I'll check the pan I put under it tomorrow and see how much its still leaking.

As for the shifter shaft seal, while the TH400 and others have a metal encased seal, the TH425 appears to only have an O-ring. Wipe the pan clean and
it soon shows if its the shifter shaft leaking. From what I can see, the shaft is above the ATF level while driving, however when sitting and leaking
down, the ATF level is above the shaft. There is no pressurized ATF on the shaft.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
 
Well, if the converter leaks down, will that raise the level in the pan above the shift lever shaft?

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
 
Johnny,
Yes, it raises the fluid by a couple of inches, well above the shifter shaft.

Not sure if replacing this O-ring seal will fix the leak as I'm sure the housing and the shaft are worn a bit after 40yrs.
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
 
This would explain why there's leaks sitting but not so much on the road.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
 
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