New bees and others on the Final Drive lube

[Bob Dunahugh]

I very seldom hear that owns have changed the FD lube. I change mine ever=
y 30,000 miles. That comes out to every other trans fluid/ filter change. O=
ils cheep. After getting the trans in Barb's 73 GMC. I pulled the FD cover =
off at the end of the day so it could drip all night. And that it did. The =
gear lube came out like maple syrup on a 10 degree Winter day in Iowa. 14 =
hours later. Still slowly dripping. And way be on black. It had mineral bas=
e lube in it. Can't get it all out. So I stayed with it. It did the job for=
44 years, and 200,000 miles. No reason to change at this point. Personall=
y. I wouldn't change to synthetic unless you can clean ALL the old lube ou=
t for sure. So. When was your FD lube changed? If you change the lube. Chec=
k with those here about the special gasket with the vent passages. Then how=
to find/clean the tiny hole in the cover. You need no mechanical skills to=
do this task. 1/2" socket or wrench, drain container, spray gasket adhesiv=
e, scraper of some kind/ single edge razor blade, a solvent to clean gasket=
area, and 2 qts of gear lube. Bob Dunahugh

 

[Bruce Hart]

Might want to add a oil drain plug to make the next oil change easy and
quicker.

> I very seldom hear that owns have changed the FD lube. I change mine
> every 30,000 miles. That comes out to every other trans fluid/ filter
> change. Oils cheep. After getting the trans in Barb's 73 GMC. I pulled the
> FD cover off at the end of the day so it could drip all night. And that it
> did. The gear lube came out like maple syrup on a 10 degree Winter day in
> Iowa. 14 hours later. Still slowly dripping. And way be on black. It had
> mineral base lube in it. Can't get it all out. So I stayed with it. It did
> the job for 44 years, and 200,000 miles. No reason to change at this
> point. Personally. I wouldn't change to synthetic unless you can clean
> ALL the old lube out for sure. So. When was your FD lube changed? If you
> change the lube. Check with those here about the special gasket with the
> vent passages. Then how to find/clean the tiny hole in the cover. You need
> no mechanical skills to do this task. 1/2" socket or wrench, drain
> container, spray gasket adhesive, scraper of some kind/ single edge razor
> blade, a solvent to clean gasket area, and 2 qts of gear lube. Bob Dunahugh
> _______________________________________________
> GMCnet mailing list
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--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class

 

[bob heller]

Bob,

I change the FD oil about every 2 years. On my GMC it's really easy because of several mods:

1. I put on a Ragusa cover that has a drain plug. Really easy to drain the oil.

2. I do not use that gasket with the hokey vent. I RTV'ed the cover on, adapted a 1/4 hose barb to where the fill plug is screwed in to (just standard
brass fittings IIRC), and ran a 1/4" hose up to a pint catch can mounted to the edge of the a/c evap housing under the left hood. Using another brass
fitting I made a filtered vent that screws into the top of the catch can. This way the venting is way up off the ground, not down near the road where
the water is. Now I don't get water into the FD through a low-mounted vent hole when crashing huge puddles or driving on I-275 during a major storm
when there is 4 inches of water on the roadway and I'm going too fast and throwing a huge rooster tail of water (the GMC can throw a bigger rooster
tail than any vehicle I've ever owned). The catch can allows me to really fill (overfill) the FD and the expanding excess oil has somewhere to go.

Also, refilling the drained FD is easy. I put a pint of oil into the catch can, wait a few hours for the oil to run down to the FD, put in another
pint, repeat until I've put in about 5 pints. If I needed to fill the FD in a hurry I can unscrew the fitting at the fill plug and put all the oil in
there the normal way. I'm just never in a hurry so I do it the easy way from the top.

I've been running this on the original 3.07 FD for just over 10 years now with the exception of a couple of years when I had a 3.21 FD installed (I
rigged the catch can to the 3.21's fill plug too, just a different size fitting). I put the 3.07 back in because it's better for what I need. It still
works fine and doesn't make any noise with about 130K miles on it.

For the gear oil, some have said to use 80W-90 and others have said to use 85W-140. I compromised and use about half of each. Nothing special,
Walmart's house brand seems to work fine and is priced right.

As usual, YMMV, JWID, IYDWIDYDME (if you do what I did your diff may explode).

--
Bob Heller
1974 X-Canyonlands 26ft
Original 455 exc for timing chain,
Rockwell intake, valve covers. 141k miles.
Winter Springs FL

 

[jim kanomata1]

The 3.07 style has a small vent hole, but a baffle shield over the vent
hole which lot have neglected to install.
Without the shield, water can impact in that hole, but if you lift the
coach and look, you'll see that its hard for water to splash directly into
the hole.
You have a valid reason for doing what your doing, but feel that majority
can do the cover like it should and not bother with the more effective
option.

 

[Matt Colie]

I have some very special concern here.

When I last bought a final drive gasket, it came in a Fel-Pro package, but it was partly made on the aftermarket tool that was mine at McCord. I say
partly because the parts that my group shipped had the vent coined into on of the two layers of the gasket. So, I got out a piece of wire and an
hammer and coined the slot myself.

I have no clue what a normal human might do in this case.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Still Loving OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

 

[Keith V]

Matt,

I don't understand the fix you did.

when you say 'coined' is that just making a dent in the gasket??

________________________________
From: Gmclist on behalf of Matt Colie
Sent: Monday, April 24, 2017 8:44:57 AM
To: gmclist
Subject: Re: [GMCnet] New bees and others on the Final Drive lube

I have some very special concern here.

When I last bought a final drive gasket, it came in a Fel-Pro package, but it was partly made on the aftermarket tool that was mine at McCord. I say
partly because the parts that my group shipped had the vent coined into on of the two layers of the gasket. So, I got out a piece of wire and an
hammer and coined the slot myself.

I have no clue what a normal human might do in this case.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Still Loving OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

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[Matt Colie]

> Matt,
>
> I don't understand the fix you did.
>
> when you say 'coined' is that just making a dent in the gasket??
>
> => Yes, that is what I did. This has to be done carefully or the gasket material will crack. While that may not actually matter to function, we
> had to reject the cracked parts as loose paper chips were not allowed.
>
> Matt
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> Subject: Re: [GMCnet] New bees and others on the Final Drive lube
>
> I have some very special concern here.
>
> When I last bought a final drive gasket, it came in a Fel-Pro package, but it was partly made on the aftermarket tool that was mine at McCord. I
> say
> partly because the parts that my group shipped had the vent coined into on of the two layers of the gasket. So, I got out a piece of wire and an
> hammer and coined the slot myself.
>
> I have no clue what a normal human might do in this case.
>
> Matt
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Still Loving 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
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Still Loving OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit