Banjo rear lube level

phartman

phartman

Senior Member
A simple question, but....

What is the best way to check the lube level in the differential, other than sticking my finger down in the access hole? And what is the best way to add lube without overfilling?

I understand the proper lube level is an inch or so below the hole, but how will I know how much to add?

Am I missing a simple answer here?

Thanks.
 
You can run any number of modern gear lubricants in the rear axle. SAE 90 summer & SAE 80 winter were the old single grade types. You can run SAE 140 if you have a leaking problem or your in a high temp region. Multi-viscosity lubes like SAE 85W/140 can be used since there is no worry of yellow metal deterioration like the old transmissions had problems with.

I use a lube gun with a set volume to fill all the stuff under a car or truck. You can draw a set amount into the gun and then keep track of how much you need to put into the gun in order to properly fill the component. If the gun holds a quart and your componant needs 3-quarts, it's pretty easy to manage that way. The only other problem is converting from pounds to liquid measure since so many of the old manuals call out lubricant in pounds.
 
Out of curiosity, why not just stick your index finger in...to first joint? If you can touch lube your good to go. If not fill till you can. Or you could make a 'tool' that imitates your finger bend...and place that into fill hole to perform same same,eh!
One caveat tho....don't be tempted to just fill/overfill till lube runs out the hole. Cause if you have substandard seals and / or WRONG lube...you will eventually find that lube in places that will cause you heartache!
 
Wait a minute - if ford drilled a level plug in the casing, then that is the level, surely, where did this setting it to an inch below come from?
The ford factory are not going to drill the hole an inch above where it should be???

Is it just that in practice the rear will run perfectly happily with the level a little lower than full and will tend to leak less??

Is that what we are talking here??

I must admit I've always filled till it came out, let it drip for a few minutes then plugged em up.

Don't worry, with a bit of driving, it'll end up lower anyway. ;)

Mart.
 
OK, I think I have an answer. I am told that the fill level is 1/2" below the opening when COLD: and level with the fill hole when HOT. That would make sense.

Am I correct here???
 
I use 600 # in my 34 both ****** & differential, it was the recommended lube at the time, however with todays modern lubricants ???. And I do keep the differential level down one finger joint. So far so good.
Gary.
 
My 32 to 41 shop manual says"Add extreme pressure gear oil to level of filler plug hole" on page 31 at the top of lubrication chart. It also says "temperatures over 90 use S.A.E 140 and temperatures between 15 and 90 use S.A.E. 90"
 
From '32 up Ford recommended SAE gear oils meant for the sliding contact of the curved teeth, NOT 600! The first modernish lube spec in '32 (I don't have the owner's manual here) was some odd SAE number no longer made, like 220, by the mid '30's the modern viscosities of 90 and 140 were in the books and replaced the earlier numbers entirely in service books. 600 is a relic of pre-EP days and was NEVER the lube specified for V8 Fords.
 
I'm not sure about the pre-war vehicles but post war car & commercial rear axles capacity is 2 1/2-pints. That's only a cup more than a quart. Some of these old books have misleading information programed in. It will tell you a capacity of 2 1/4 pints in one section then in another it will tell you to fill with 2 3/4 pints. It will then tell you to top it up to the filler hole. It has always led to a lot on confusion about what is correct. If a person drains the housing & adds 2 1/4 pints back in, you might be surprised where the level ends up. Overfilling can cause other problems.
 
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Bruce Lancaster said:
From '32 up Ford recommended SAE gear oils meant for the sliding contact of the curved teeth, NOT 600! The first modernish lube spec in '32 (I don't have the owner's manual here) was some odd SAE number no longer made, like 220, by the mid '30's the modern viscosities of 90 and 140 were in the books and replaced the earlier numbers entirely in service books. 600 is a relic of pre-EP days and was NEVER the lube specified for V8 Fords.
Click to expand...

Bruce, would you recommend the straight weight or the multi -viscosity?

And what about the SAE specifications?

The 85/90 weight Pennzoil marine is what I use in my outboard lower unit. What SAE codes are applicable for the banjo rear so I can check on the lube container to see if the same lube can be used in both the outboard and the differential?
 
I've always used parts store 140. I know NOTHING about modern synthetics and details of designations but suspect that anything available from a decent company is plenty.
Note that the banjo uses spiral cut gears, the reason for needing modern type EP and the reason Ford changed to the ancestral form of that in 1932, but it should be easier to keep happy than later rears whose hypoid construction (pinion not on center of ring) adds a lot more sliding stress.
There are rumors around about modern additives attacking brass, as in the trans synchros, but I have been told that is only an issue at very unlikely temperatuire levels...don't know anything first-hand on that but suspect it is just another scare like lead and zinc...help, help, the old car hobby is dead because new stuff will dissolve our engines!!
 
Sulphurics will do some harm to phosphor bronze bushings over time if left to set there to mix with condensation and other factors. I don't think it really affects the brass blockers at all. Most folks baby there old cars and don't let them set in poor conditions for long periods anyway. They might set a long time but out in the weather is asking for a re-restoration of any kind of machinery. I've used GL-5 SAE 85W/140 in helicopter transmissions for years and have never seen any adverse effects on brass cages of bearings in there but I have seen entrapped moisture rot near through the magnesium lower sump housings. Magnesium is a whole different material than anything in an old Ford ******.

Any oil is better than no oil in my book. Just something close to OEM recommendations in viscosity will do.
 
Boy, this is like a : "What kind of oil should I use?" thread.
Do you think every corner gas station that had a lube rack had a specific rear end oil for ford, gm, chrysler, pierce arrow, packard,etc?? And how many "kids" on the rack used one "joint" low, to the top, running out. The majority of the cars survived. Or what about the kid with ahort fingers or the kid with real loong finger joints. Me thinks some worry too much..............KISS JMO
Paul in CT
 
Always figured full was when fluid drooled out of the hole . If you can touch fluid you should be OK . This is nothing more than safe operating range . Full is still full though & do you normally run stuff with lube levels on the danger mark ? Probably not .
phartman said:
A simple question, but....



I understand the proper lube level is an inch or so below the hole, but how will I know how much to add?

Am I missing a simple answer here?

Thanks.
Click to expand...
 
I checked the API service recommendation on the Pennzoil marine lube that I had on hand- 80/90 weight for lower units and stern drives. It is recommended for GL 5 service. The Pennzoil gear lube I bought yesterday is GL4 and GL5 service. What is the difference? Here is an excellent article from the Corvair club that goes into quite a bit of detail.

Some interesting notes from the article:

1) Follow the recommendations of your car manufacturer

2) Don't overdo it on the modern additives.

3) Be careful what you use in your transmission. It may not be the same as what is in your differential (I didn't know that).

Here's the article:

http://www.widman.biz/uploads/Transaxle_oil.pdf

As far as the Mac's 600W Oil, there is no API rating on the container, and no indication what the application is intended for. It does, however, make an interesting note that many leaks are caused by overfilling of the differential or using the wrong lube. They indicate the rear should only be about 1/3rd full with gear lube.

I did check the recommendation in my 1937 Ford manual, and it is exactly what Bruce posted earlier. Nothing in the manual suggests anything remotely like 600 weight.

I'm doing what Bruce says. I drained the 600 and replaced with the 85/140 Pennzoil.

And for the record, when I examined the used Mac's 600 wt. lube, it had about 1200 miles on it. It looked perfectly normal, and nothing unusual showed up in the pan.

You'll have to make your own decision here.
 
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And this thread from the VW community on GL4 vs. GL5 lubes. Wow, did I stumble into a hornet's nest. Sheesh. But the bottom line seems to be GL5 does not supercede GL4, and if the specs call for GL4, then use that.

So- at the risk of putting certain members here over the edge- the Ford Toploader transmission? GL4 or GL5? Same gear lube as in the rear end?

Here's the VW article:

http://www.westfalia.org/community/...transmission-fluid-in-GL-4-spec-transmissions
 
The specs originally called for GL3 which is long ago gone. GL4 has a little more EP than the GL3 and is entended for light duty hypoid use. GL5 is for medium to heavy duty hypoid type use. The old GL3 was for gear to gear use or non-hypoid type differentials and mild EP for early transmissions with & without overdrive. The only way you can get close to GL3 is to buy GL1 lube & mix with GL4 lube but I know of no one who goes to this trouble. GL1 will work for older transmisions just fine but lacks the EP for the rear axle unless you have an old truck with a worm screw drive.

I wouldn't get worried at all about using GL4 for multi-purpose on the old transmissions & rear axles. GL5 should be OK too if you treat you car like a king and change fluids regularly.
 
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