MTFCA Forum

I hope this isn’t a Marvel Mystery Oil, which engine oil should I use?, which grade gas is best? knock-down drag-out discussion thread.
I had several local T club members over for a barbecue yesterday.
I mentioned that I recently rebuilt and installed the rear and driveshaft on my ‘24 Touring.
When I also mentioned that I was going to add the STP 85W-140 pictured, several members insisted that I use 600 weight oil instead.
Comments appreciated.
Please be civil.
LoL
Gene

Yep, Gene, order the bottle of 600 from Langs. Best bet, made specifically for the T. I believe one bottle will be more than enough.

BTW...why in the world are you STILL UP at 3 A.M.!!?!!

I would also like to hear some reasons why to not use a more modern viscosity gear lube. Seal leakage? I don’t want to hear because Henry did it that way, oils have come a long way since then. I run 90 synthetic in my model A housing without problems at all.
Thanks

I run 85W-140 in my rear end too because I have a Ruckstell axle. 600W is too heavy to get into all the nooks and crannies of it.

Need to check the GL of gear oil to see if suitable for bronze parts. GL5 is very high in sulfur so not an oil of choice for bronze.

Best to review some past discussions - may depend on the parts used to do the rebuild.
These links have many owners using 85W-140
http://www.mtfca.com/discus/messages/82 ... 1515174876
http://www.mtfca.com/discus/messages/50 ... 1433273952
http://www.mtfca.com/discus/messages/25 ... 1355711752
Also much discussion about the effect of additives on brass - not to worry

Tim,
Couldn't sleep due to dreaming about everything that needs to be done before school opens in late August!
I guess I'm becoming neurotic after 35 years in education.

Lol,
Gene

Oh Gene...so sorry. Been there done that!
Glad I'm retired from it!
Good luck with the new year opening amidst all this virus confusion, etc.

I replaced whatever WAS in my diff. with the 600 weight oil from Lang's. I was amazed at how quiet my rear end became. Basic Flivver logic: Quieter = Better.

Rebuilt 3 rear ends and have been using GL 4 SAE 140 Gear Oil in them. Works well and has a lot of "cling". Pretty popular with the tractor folks in my neck of the woods as well.

No long term experience here but I have just tried Lucas hub oil in my rear axle. I figure truck hubs are about the nastiest environment that oil could live in so it must be good stuff. I may regret it you never know. One way to find out though. It’s just money right?

What is wrong with just using 600w? I heard long ago that too thin an oil can lead to axle seal leaks. I can't remember who told me and do not know what weight to give that recollection. I ran 600w in the axle before the installation of the Ruckstell and then switched to 90w. No oil leaks so far . . .

Paul

I pack my wheel bearings with 600 weight

600 WT is more of a liquid grease. Load pressure and torque in a Model T differential is different in the term of bearings. The Hyatt bearings on the inside do require a much thicker weight to compensate this long anti-friction process due to their spiral roll. High speed 90 degree non hypoid gears like thick oil/grease. Have seen excessive wear on the bearings over the years due to improper gear lube..., Just Sayin' what has been observed. I do use a 50/50 mix of 85-140 WT and Lucas additive in my Warford's and other accessory transmissions with excellent results. To each their own in the pursuit of happiness.

Hope this Helps,

Hank

600w gear oil is recommended for the rearmed due to the fact that it remains in the pumpkin. Lesser viscosity oils can find their way past the seals and end up in the shaft housings, and brake drums and eventually on the floor of your garage. Needless to say, gear oil does a lot more good in the pumpkin than in the shaft housings. Jim Patrick

When I was getting Henrietta back on the road, I checked the pumpkin for lubricant. I found it packed with grease, so I screwed the plug back in and we motor on. When I have to tear it down, I will be interested to investigate further.

Allan from down under.

When rebuilding, If you use the newer neoprene inner seals, then leakage will not be an issue. The 85w-140 we use in Ruckstells does not leak past those seals. Make sure you do not fill too full. GL-3 is still being made, which is best on the bronze parts but is harder to find. So most use the GL-4.

Keep in mind that 600w rear end oil is on the ISO scale, not the SAE scale. SAE-600 would be like peanut butter. Here's the equivalency chart (also note that SAE engine oil is on a different scale yet): That said, 85w-140 GL4 is a good choice for a stock rear end, and 85w-90 GL4 for a Ruckstell. They all need good outer-axle seals, including the original 600w.

I have been using something called "portable grease". I got it from a friend of mine who has several restored T's. He also has some of the largest cranes in the south east for his business. This product is what is used for gear boxes etc. on these cranes. He has used it in the T's for ever and it remains effective without problems. His T's run in several of our club tours and never have had a rear end problem. I don't know where he gets it but it is in 25-40 gal. containers.

If I'm reading the chart correctly, 600 W would correspond to about a 160 W gear oil. I'd think that 140 W with about 25% of one of the STP-type additives recommended for gear cases would be a close match in everything but color. If you want the brown-black goop look, add a little graphite or dry powdered roux.

Re: Marvel Mystery Oil... If your T gets creepy in the Fall, add a pint or two of Marvel Mystery Oil to the crank case.

In a past life, I used to run a 13A D8 Cat bulldozer clearing trees in a N.W. MO. timber. We used 85W-140 lube in the final drives because the "bellows" seals leaked a bit. I think that will work just fine in a T, at least it does on mine. JMHO Dave

T rear ends never had oil in them just non flowing grease. Originally it was #2 grease that was adequate for most climates and to get the car out of the factory. There are mentions of using the "correct compound" for your differential, a compound consists of at least two parts. T differentials had no seals just dust felts to prevent dust from entering the bearing housing, these were not seals. Some manuals refer to the differential plug as a grease plug and some an oil plug. With grease it will not drain and the plug is only there to fill the housing with grease (two - two an a half pounds) Some have commented that the ring gear will just cut a swath in the grease and it will not lubricate. This would be true if the grease was too heavy, there are different grades/weights of grease the same as oil. A creamy non-flowing grease is ideal something like soft butter. I tested some grease samples on a sheet of glass on a hot day and #2 was too heavy, # 1-1.5 was just right it would just slump in the hot sun but but not flow, the #2 was too firm. The outer bearings are packed with grease when installed and topped up when necessary with the grease cups. The only to "drain" the housing is to disassemble it.

Spot on David. Every "unaltered" rear end I've opened up with that sticky goop, made me wonder how in the heck it even DID
lubricate the works! I really like the "600W" (which is really a mis-nomer) from the vendors. No doubt it lubes everything in its path in there.

For the Ruckstell I use 85w-90. Sta-Lub GL-4. Buy it at local Napa Parts store. GL-4 seems to be harder to find as time goes on but Sta-lube still makes it and NAPA carries it here.

The early manufactures of Ruxtels claim that the correct grease in the differential housing is adequate for the added Ruxtel, just the shifting mechinasium housing has to be packed with grease and that is all. They claim that there are no moving parts in the Ruxtel to require any additional lubrication. I have never owned one and never had one apart.

Henry K. Lee wrote: ↑

Tue Aug 03, 2021 8:08 pm

600 WT is more of a liquid grease. Load pressure and torque in a Model T differential is different in the term of bearings. The Hyatt bearings on the inside do require a much thicker weight to compensate this long anti-friction process due to their spiral roll. .., Just Sayin' what has been observed. (quote abridged shorter by me )
Hank

Will agree with Hank and others, that Ford specified the heavy fluid grease "600w" for the rear axle for good reasons. The gear type of the ring and pinion, those thrust washers, and the Hyatts inside. All benefit from a thick fluid grease.

This label is from an old can of 600w sold via Snyder's years ago and identifies this lubricant as close to SAE 250 fluid grease. 600w is what I have always placed in stock T rear axles, and minimal leakage, and maximum protection.


Another reason too is that the rear axle is exposed to the exhaust gases from the T muffler end, and of course, there is the heat from friction, all this heat can make a thinner rear axle oil like 85w-140 become even more less viscous. For me, stick with 600w, the gears like it sticky too.