Transmission / Overdrive: More oil questions

[evilhawk]

I am sure this question has been posted numerous times, but I am having troubles finding information on the subject. I just got my 59 Hawk running after a 36+ year hibernation and want to start driving the car. My question is, What type of gear box oil and rear end oil would you recommend? The car has a manual B&W 3 speed O/D trans and a 44 twin traction rear end.

Also, do I need to add zinc to the engine oil? I filled it with Valvoline 10w30, but a concerned friend recommended I add zinc..

Thanks in advance!

Sam

[dynolou2]

For the rearend GL 4 or GL 5 80/90 weight and a friction modifier from a ford or gm dealer or a differential repair shop. Lou Cote

[Kurt]

GL 1 90w for the overdrive. I think 40w non detergent engine oil is also something you can use in the overdrive.

As as for adding zinc my answer is yes. Others may tell you different. Lots of reading on this topic if you do a search. Currently I use Valvoline VR1 racing oil as it comes with enough zinc already in it.

[StudeNewby]

Ask for a limited-slip differential oil at your FLAPS; it is readily available. As for motor oil, Walmart sells Quaker State Defy for under $16 for five quarts in our area. It has added zinc. I use it in all my cars, and I've been quite pleased.

[colt45sa]

I can't believe that you folks actually consider the cost of a quart of motor oil for your Studebaker. Its not as though you change it every two months and that the cost of operation and maintenance is going to be too high at an extra few dollars a quart for motor oil. Geez !! Kurt has it right. Do your research and you won't have to buy a 'zinc additive'.

[Paul Keller]

The trans' oil suggested (40 wt non-detergent) is available from FOB that service light aircraft at airports - It is pricey, but you only need one (1) quart - Plus another to keep on-hand (saves an extra trip to the airport). Have used it w/ great results (new oil can make a big difference in its operation). Check your Stude' Repair manual to make sure it is OK for use in the overdrive (the recommended lube is in the Lubrication Section.

Paul TK

[Bud]

I've used GL1 SAE 90 gear oil in Studebaker transmissions along with SAE 40 engine oil, but in recent history, I've been using Amsoil Manual Transmission and Transaxle oil which is an SAE 75W-90. It's meant for use in manual transmissions with yellow metal parts. In every transmission I've put it in the transmission shifts a bunch smoother with no problem with the synchros. The oil is expensive, but manual transmissions don't use much oil and the oil isn't changed very often, so to me, the price isn't a big problem. Bud

[Bud]

I almost forgot, I don't like the idea of adding anything to engine oil as the additive could compromise the additive package already in the oil. Use an oil that already has enough ZDDP in it such as Chevron Delo 400, Shell Rotella T or Valvoline VR1 racing oil. As far as differential lube, use an oil from one of the big suppliers as most of their oils already have a friction modifier in the oil. I like Mobil 1 LS 75W-90 or Amsoil Severe Gear 75W-90 oil. Both are full synthetic oils and work really well in Studebaker differentials with twin traction. Bud

[evilhawk]

Thanks everyone for the suggestions. I went to my local auto parts store yesterday to try to find trans and rear diff oil. I couldnt find the trans oil (GL1 90w), but I did find Valvoline 75w-90 for limited slip rear ends. The guy at the counter said it should work in the stude twin traction rear end, but I wanted to double check with you guys.

[StudeRich]

It is not so much about the "Weight" or Brand of the Oil Products as it is the "GL" rating number, THE most important feature!

GL-1 is available at Farm and Tractor Stores and more commonly at NAPA Stores in Gallons, it may need to be ordered.

On a full Differential Fill after draining, I do not depend on only the Gl-5 for limited slip Diffs. to adequately protect the TT Clutches in my Dana Twin Traction axles, I add the 4 OZ. bottle of Limited Slip Friction Modifier to the GL-5 and have good results. It is at Car Dealer Parts Dept's. and all Auto Parts Stores.

[voxnut]

In the '61 Lark Regal wagon, I use Brad Penn motor oil (I order mine from Summit Racing) and GL1 Ford Tractor 90wt mineral oil that I picked up at a place out here called Tractor Supply. For the TT rear end, I've got Castrol API GL-5 Limited Slip Gear Oil.

[evilhawk]

Well the Valvoline High Performance gear oil states that it is recommended for hypoid differentials (conventional and limited slip) where API GL-4 or GL-5 is specified. I am thinking of picking some up and maybe add a friction modifier. What do you guys think?

[karterfred88]

Well the Valvoline High Performance gear oil states that it is recommended for hypoid differentials (conventional and limited slip) where API GL-4 or GL-5 is specified. I am thinking of picking some up and maybe add a friction modifier. What do you guys think?

Don't bother with the friction modifier- it's already in there with the Valvoline differential oil. Like Zinc too much of a good thing can be bad.