Final Drive ( 3.21 ) Gear Oil Capacity

[larry.whisler]

I just finished installing a 3.21 final drive in the coach.

What is the capacity of the 3.21 final drive?

I checked the 67 Olds Toronado manual on the 3.21 and it states 4 1/2 pints
and I thought that I had read somewhere out here on the forum that the
3.21 final drive should not be filled to the hole in the cover but rather
the fluid should be an inch or two below the hole.

So I add two quarts of gear lube and just as I am finishing up the second quart
it starts running out the hole.

Am I missing something? or is the manual a misprint? The drive was completely empty
when I installed it.

larry

 

[adolph santorine]

Larry:

I filled the 3.70 in my coach to the hole.

I don’t know for certain if that’s right, so I’m going to follow what you learn here.

Dolph

DE N8JPC

Wheeling, West Virginia

1977 26’ ex-PalmBeach
1-Ton, Sullybilt Bags, Reaction Arms, 3.70 LSD, Manny Transmission, EV-6010

“The Aluminum and Fiberglass Mistress"

>
> I just finished installing a 3.21 final drive in the coach.
>
> What is the capacity of the 3.21 final drive?
>
> I checked the 67 Olds Toronado manual on the 3.21 and it states 4 1/2 pints
> and I thought that I had read somewhere out here on the forum that the
> 3.21 final drive should not be filled to the hole in the cover but rather
> the fluid should be an inch or two below the hole.
>
> So I add two quarts of gear lube and just as I am finishing up the second quart
> it starts running out the hole.
>
> Am I missing something? or is the manual a misprint? The drive was completely empty
> when I installed it.
>
> larry
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[jhb1]

Hi Larry when I changed the fluid on mine I used a little less than 2 quarts there is about an inch and a half left in the second bottle when it
started to flow out.. Takes awhile to settle out when filling

HTH
--
John H. Bell
77 Royale; QuadBag,Manny OneTon,Honda EV4010
Montreal Qc.

 

[kab7]

About 1.75 quarts. I just did this yesterday with a Manny-rebuilt 3.21.

Manny got Ragusa 3.21 covers without the fill hole drilled so he could place it lower
than Ragusa was doing because he said filling it too high with oil was causing problems.

Karen
1975 26'

 

[larry.whisler]

I have the stock 3.21 cover. i'll check the oil level tomorrow
and see where it's at. I'll probably bend a piece of wire to check
it with.

I am hoping that after settling it is about 2 inches from the bottom
of the hole.

larry

 

[robert mueller]

Dolph,

The case on a 3.21 t0 1 is a planetary gear FD and the case is smaller.

Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Dolph Santorine
Sent: Tuesday, September 20, 2016 6:52 AM
To: GMC List
Subject: Re: [GMCnet] Final Drive ( 3.21 ) Gear Oil Capacity

Larry:

I filled the 3.70 in my coach to the hole.

I don't know for certain if that's right, so I'm going to follow what you learn here.

Dolph

 

[jim kanomata1]

3.21 is different than the 3.07 unit.
From what I learned when I did run a 3.21 back in 1982 was that the level
was creating a problem and one of the way to avoid the issue of burping out
was to run it lower.
Larry, I believe you have a baffled vent on your cover to help avoid this.
I ran my vent tube to the height of the tire to assure that it had less
chance of expending fluid
I know the synthetic fluid will also help as the temperature runs lot
cooler.

On Mon, Sep 19, 2016 at 5:43 PM, larry.whisler
wrote:

> I have the stock 3.21 cover. i'll check the oil level tomorrow
> and see where it's at. I'll probably bend a piece of wire to check
> it with.
>
> I am hoping that after settling it is about 2 inches from the bottom
> of the hole.
>
> larry
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

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

 

[adolph santorine]

Thanks. I see that now (I knew there was a reason to have that Oldsmobile manual).

Dolph

DE N8JPC

Wheeling, West Virginia

1977 26’ ex-PalmBeach
1-Ton, Sullybilt Bags, Reaction Arms, 3.70 LSD, Manny Transmission, EV-6010

“The Aluminum and Fiberglass Mistress"

>
> Dolph,
>
> The case on a 3.21 t0 1 is a planetary gear FD and the case is smaller.
>
> Regards,
> Rob M.
> USAussie - Downunder
> AUS '75 Avion - The Blue Streak TZE365V100428
> USA '75 Avion - Double Trouble TZE365V100426
>
> -----Original Message-----
> From: Gmclist [mailto:gmclist-bounces] On Behalf Of Dolph Santorine
> Sent: Tuesday, September 20, 2016 6:52 AM
> To: GMC List
> Subject: Re: [GMCnet] Final Drive ( 3.21 ) Gear Oil Capacity
>
> Larry:
>
> I filled the 3.70 in my coach to the hole.
>
> I don't know for certain if that's right, so I'm going to follow what you learn here.
>
> Dolph
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[LarryW]

Larry, The first year I ran my 3.21, if I filled it to the fill hole, it would spit out about 1" of fluid. Then I tried running it 1" low and it
never spit out any more fluid. Been running it that way since 2005 with no issues. Just make sure the vent, which is located in the center of the
left side output shaft plate is not plugged. See this:
http://www.gmcmhphotos.com/photos/fd-visual-differences307-vs-321/p16034.html

and even the rest of the photos in that album for some information on the 3.21.

Bend a 12ga wire at a 90* angle and mark it at 1". The insert in the fill hole and fill to 1" below the fill hole. No need to run another vent up
into the engine compartment like some have done. If to full it will still spit it out that high vent. JWID

HTH
--
Larry
78 Royale w/500 Caddy
Menomonie, WI.