Oils for trans and posi rear end for '62 FI

[Richard L.]

Just brought home a '62 FI car and want to refresh all fluids. What's a good currently available oil for the T-10 and the posi rear end? As far as the coolant I plan to use the old stand-by green (in yellow container) Prestone if that's still recommended.
thx
ric

[James W.]

Re: Oils for trans and posi rear end for '62 FI

Ric,

I use Lucas Oil non-synthetic 85W-140 gear oil in my '65 Corvette differential and transmission. This oil was recommended by the differential rebuilder, Gary Ramadei who is a an NCRS member and is in the Corvette differential and steering gear box rebuild/restoration business.

For the radiator, I would suggest the Zerex G05 anti-freeze and distilled water after a thorough flush of the system.

Hope this helps.

James

[Richard L.]

Re: Oils for trans and posi rear end for '62 FI

But are you sure that the independent rear of the 65 and the solid axle 62 have the same innards and thus both use the same lube recommended by your tech? By the way, Amazon or NAPA for sourcing it?

[Duke W.]

Re: Oils for trans and posi rear end for '62 FI

The original C1, C2, early C3 transmission and axle oil specification (see your owner's manual) was Mil-L-2105 This mil spec was cancelled in the seventies and replaced with the commercial API SAE 80W-90 GL-5 spec that you can buy and any auto parts or big box store.

BRAND MAKES NO DIFFERNCE!!!

Just buy the API spec. Look for it on the API "donut", which is usually on the back of the bottle. If the axle is Positraction you will also need at least one 4-oz bottle of Positraction additive. You don't have to buy it from GM. NAPA and other parts change have it too. All clutch type LSDs use the same friction modifier regardless of manufacturer.

Trans and axle capacities are in owner's manuals, service manuals, and the AMA specs that are a free download from the GM Heritage Web site.

Use HOAT type Zerex G-05 antifreeze, 50-60 percent mixed with distilled water.

The old IAT type "green" antifreeze offered good protection, but the inorganic chemicals, mainly silicates, clogged up radiators. OAT types currently used by most manufacturers may not provide good protection for soldered components like heater cores and radiators in most vintage cars.

HOAT types like Zerex G-05 are the new "universal" antifreeze that provides excellent protection for all cooling system materials including solder without clogging up radiators and heater cores.

Duke

[Richard L.]

Re: Oils for trans and posi rear end for '62 FI

Thank you James and Duke. What thermostat should I use, the car is black/black and I'd like it to run as cool as possible since it's also a fuelie and gas being what it is, idling and running in town can be nerve racking. Can I use a 160 degree thermostat with no ill effects?

[Terry D.]

Re: Oils for trans and posi rear end for '62 FI

Running a 160 stat does nothing to cool the engine. It just opens sooner than the 180. Make sure your fan is located halfway in the shroud, as mentioned flush radiator, seal around the shroud as best you can, make sure fan clutch is working properly. Also make sure timing is correct. Know nothing about fuel injection but someone with that knowledge will chime in.

[Duke W.]

Re: Oils for trans and posi rear end for '62 FI

Assuming you still have the OE type dual point distributor your engine doesn't have the optimum around 28-32 degrees of total idle advance required to idle most efficiently with minimum EGT. The Chevrolet Power Manuals from the seventies state that optimum power is achieved with 36-40 degrees spark advance. The OE dual point distributor provides only 24 degrees centrifugal, so you should set initial at 16.

Since the centrifugal starts at 700 and it's tough to get a Duntov cam engine to idle stably at less than 700 long enough to adjust timing. The other method is to set timing at the recommended 36-40 (vacuum advance disconnected on single point distributors) above the speed of max centrifugal. If your distributor is unmodified, full centrifugal does not come in until 4600 so you will have to set it at over that speed. This is one advantage of bringing it in early with lighter springs in addition to the better low end torque.

A third method is to static time the engine. Place the balance notch on the desired initial timing value on the balancer. Then rotate the distributor so the points just begin to open. You can eyeball it but if you use an ohmmeter you should be within a degree. Also understand that the timing tab is not accurate on 8-inch balancer engines; 16 degrees is really only about 14.

Other issues are degraded OE components like the radiator and clutch fan. Inexpensive aftermarket copper radiators do not have the heat transfer capacity of the OE aluminum radiator. Ninety-nine percent of amateur "re-engineering" efforts to solve cooling system problems fail. The engineers who designed the Corvette cooling system back in the day knew what they were doing, and it can't be improved without spending more money that new OE equivalent components. Use OE equivalent components and make sure they function properly and are not compromised by age or damage.

Duke

[Richard L.]

Re: Oils for trans and posi rear end for '62 FI

Don't mean to make anybody mad BUT what about NAPA's own brand (which is Valvoline I believe) 75W90 Synthetic, which already has a friction modifier?

[Duke W.]

Re: Oils for trans and posi rear end for '62 FI

I'm not a big fan of synthetics in vintage transmissions and axles. There have been reports that they are more susceptible to leaking. Synthetics are more resistant to oxidation, but Positraction axle oil should be changed every 30K miles to remove all the clutch wear particles and renew the friction modifier additive, so you don't need the extended life benefit, and while your at changing the axle oil, do the transmission, too. (If the manufacturer of your modern cars recommends synthetics, I recommend that you follow their recommendations.)

A bigger problem is that many owners of vintage cars don't maintain comprehensive service records and few vintage car sales include such maintenance and repair records, and most are likely maintenance deficient, particularly fluids other than engine oil.

Over the years I've seen gear oil bottles (I recall Valvoline was one) that state "suitable for limited slip differentials", but the product didn't actually contain the friction modifier additive, so how do you really know?

If you buy from NAPA why not buy plain vanilla SAE 80W-90 assuming it has the API donut with the GL-5 service rating? It's unlikely that it has the friction modifier, but you can buy that from NAPA too. Start with one 4-0z. bottle (part number NCB 4285V). Leave room for a few more ounces of oil if there is any clutch chatter and you need more additive. "Full" is to the bottom of the fill plug with the oil hot - at operating temperature and up to a quarter inch below is okay for normal road service.

As far as higher viscosity gear oils like 85W-140 are concerned they are usually only manufacturer recommended for heavy duty axles and transmissions like Class 8 big rigs, and off highway HD equipment. I don't know of any manufacturers that recommend anything more viscous than 80W-90 for car and light duty truck axles.

The biggest problem is that consumers are bombarded with advertising to use their super duper (and very expensive) lubricants and additives to protect their cherished vintage car even though the modern common equivalents of the lubricants installed at the factory are superior to those factory installed lubricants that rarely caused problems over the subsequent decades and many tens of thousands miles, but it's your car, so your choice.

Duke

[Duke W.]

Re: Oils for trans and posi rear end for '62 FI

Ric,

I use Lucas Oil non-synthetic 85W-140 gear oil in my '65 Corvette differential and transmission. This oil was recommended by the differential rebuilder, Gary Ramadei who is a an NCRS member and is in the Corvette differential and steering gear box rebuild/restoration business.

For the radiator, I would suggest the Zerex G05 anti-freeze and distilled water after a thorough flush of the system.

Hope this helps.

James

Can you post a photo of the backside of the bottle so we can see if it has an API service category rating and what it is?

Duke

[Richard L.]

Re: Oils for trans and posi rear end for '62 FI

Looked at NAPA's "plain vanilla SAE 80W90" this morning. On the way home I realized that that's what I've been using in my other vintage cars so I'll go back and get the friction modifier additive (BG brand??) plus three quarts of the stuff (1 for trans and 2 for the rear end). No point in overthinking this, common sense usually prevails.

[Leif A.]

Re: Oils for trans and posi rear end for '62 FI

Can you post a photo of the backside of the bottle so we can see if it has an API service category rating and what it is?

Duke

Here ya go Duke...

[Duke W.]

Re: Oils for trans and posi rear end for '62 FI

Looked at NAPA's "plain vanilla SAE 80W90" this morning. On the way home I realized that that's what I've been using in my other vintage cars so I'll go back and get the friction modifier additive (BG brand??) plus three quarts of the stuff (1 for trans and 2 for the rear end). No point in overthinking this, common sense usually prevails.

Ah... you see the light! I don't know what you mean by "BG brand", but I listed the NAPA part number for the LSD additive in post #9, and any other parts store should be able to cross reference the NAPA number to whatever brand they sell. This product is available under many brand names including manufacturers like GM, Ford, BMW, and Diamler-Benz, and all clutch and cone type LSDs that I am aware of use the same friction modifier.

Typical wet clutches like what we see in automatic transmissions and LSDs need a friction modifier to avoid stick-slip friction often referred to as "chatter". This can take the form of mild "groaning" to side to side jerking as the clutches stick and slip while negotiating sharp turns.

Back in the fifties and sixties it was affectionately known as "whale sperm" because it was a whale oil product that was used as an additive for LSD axles to prevent wet clutch stick-slip friction, and the old Type A Suffix A ATF for the original Hydramatic automatic transmissions contained a small dose for the same purpose. But since whale products were outlawed in the USA back in the seventies, industry had to come up with a synthetic substitute.

This is a good thing beyond protecting whales because animal and vegetable, like whale and castor bean oil products, oxidize rapidly at typical transmission and axle operating temperatures, but synthetics are much more durable.

Duke

P. S. Thanks for posting the label, Leif!

[Duke W.]

Re: Oils for trans and posi rear end for '62 FI

Regarding that Lucas gear oil label I question whether this product is actually API certified because the API "donut" with the SAE viscosity and service categories is not displayed. Displaying this symbol requires that the product pass all the required API tests for the specified service categories in addition to paying a licensing fee to use the trademark symbol.

They appear to spend a lot on marketing and advertising. I'm sure they pay a hefty annual fee to have their name on that Indianapolis sports stadium.

Maybe it's legally okay to state "exceeds service level GL-5..." without getting slapped with a lawsuit for trademark infringement if the product has not gone through the certification process and is licensed. In any event, the lack of the API donut symbol makes me suspicious that this is not an API certified product.

Duke