64 Monza 4 speed - Gear Lube

[Jims_Corvair]

I have searched for this answer.

Q: what sizes of square nut to buy all at once?

Details
I checked the second dipstick and it's shows low and I need to fill it. I think this is for the trans axel. I located the filler plug on the drivers side near the left drive shaft. Unfortunately the exhaust and rear leaf spring make it a really tight spot to loosen that nut / plug. I think this is a 9/16 square female. Please correct me.

I located the same socket and was about to buy it for $12.34
https://www.amazon.com/gp/product/B006L ... 07WWNCPEAF

I'm OK with that and would buy any others at this time to be done with it. What other sizes should I buy?

More Questions
1. I noticed that there is no drain plug for this and was wondering why?
2. Is this gear lube shared with the transmission gear box?
3. Removing the drivers side rear tire seems to be the simplest way to gain access to this nut. Are there any other ways? I jacked it up, removed the wheel and can see it but still had to crawl under to get a wrench on it but couldn't remove it.


PS - I already purchased the grade 4 lube, thanks
PSS - that isn't my transmission in the photo and not my photo, credit to the guy on ebay

Any additional advice is welcome, TIA

Jim

[terribleted]

The square plug you note is the fill location. a 5/8 open wrench often fits this. a better choice I think ( I do not remember for sure as I go to the tool box and grab a socket that fits) is a 12 point 11/32" socket. With the car level you remove the plug and fill with gear oil until it rubs out some. let drain until it is done running out and re-install the plug as the transaxle is full, and yes trans and diff share fluid.

The correct fluid is SAE 80W/90 GL3 (you should know this from your GM Corvair Shop Manual...if you do not have them get them ...you need the 1961 Corvair Shop Manual and the 64 Corvair Shop Manual Suppolement...you can buy hard copies at Clark's Corvair Parts or you can see PDF's here: https://www.corvair.org/chapters/corvan ... .php#C95RP ). That's said SAE 80W/90 GL3 is obsolete but SAE 80W/90 or 85W/90 GL4 can be found and should be used. DO NOT use any gear oil specced for GL5 (this is the most common and can be found everywhere but will ruin the transmission synchronizers over time. If is says GL5 on it at all do not use it. I have been using this product Sta-lube 85W90 GL4 successfully for years now https://www.amazon.com/CRC-Sta-Lube-SL2 ... B000M8RYMC . This is just the first link I found to the product and may not be the best place to order some...shop it.

[bbodie52]

As to your transaxle gear lube question...

I guess when GM engineers dropped the transaxle drain plug to simplify production and to save a little in the cost of manufacturing the Corvair, they assumed that Corvairs only had a life expectancy of 10 years or so and would be junked before they needed a change in transaxle gear lube. History has proven otherwise! Unfortunately, there is no easy way to drain the differential and manual transmission in many Corvairs, which literally sucks!

Tue Nov 07, 2017 11:32 am

... DO NOT USE Redline MT-90 in a Corvair transaxle. Redline's site specifically states that MT-90 is NOT approved for hypoid gears (differential). So it is NOT acceptable for use in a Corvair transaxle since protection for the ring and pinion differential gears is inadequate. Redline does make a modified GL-5 lube that is suppose to work with brass synchronizers called - 75W90 NS GL-5 and states it's approved for transaxles with brass parts. NOTE: Redline NS GL-5 is different vs. their GL-5 which is NOT approved for transaxle use.

I did not know that about their gear lube products. The bottle lable states that it is suitable for transaxles, but the website states otherwise!

https://www.redlineoil.com/mt-90-75w90-gl-4-gear-oil

Since most GL-5 gear oils for differentials are too slippery for manual transmissions, Red Line offers these products that ensure proper shifting while providing ultimate wear protection

Appropriate coefficient of friction for most manual transmission synchronizers (other's synthetic gear oils are often too slippery for proper synchro engagement)
Red Line offers lubricants to pinpoint nearly every transmission application
MTL, MT-85 & MT-90 are not for use in differentials with hypoid gears
Excellent gear and synchro protection, balanced slipperiness for easier shifting in cold climates
Excellent for high- and low-mile transmissions
Compatible with petroleums and other synthetics

Red Line MT-90_GO_PROD_INFO.pdf

And you are using GL-4 gear lube to fill your transaxle, right? NOT GL-5!

My research indicates that Red Line makes two separate gear lubricant products. One is specifically for use in manual transmissions, that include YELLOW METAL synchros. The Red Line gear lube manual transmission oils are rated as GL-4, but the fine print also specifically states that this GL-4 gear lubricant is NOT FOR USE IN HYPOID GEAR DIFFERENTIALS (the Corvair differential uses hypoid gears). The other Red Line gear lubricant products are GL-5 and are for use in differentials, but are not for manual transmissions. Because of this, neither of the Red Line series of gear lube products are suitable for use in a transaxle that shares fluid between the manual transmission section and the differential section.

See the material at the bottom of the following thread: viewtopic.php?f=52&t=15340&p=106565&hil ... ne#p106565

As mentioned in the above thread...

MAX GEAR – HIGH PERFORMANCE SYNTHETIC GEAR OIL
Max Gear – High Performance Synthetic Gear Oil
Max Gear is recommended for use in truck and automotive front or rear differentials, manual transmissions and lower gear units of marine engines that specify use of an API GL-5 or GL-4 fluid. It is non-corrosive to soft yellow metals (brass, bronze, copper, etc.) and synchronizer safe. Specially designed to extend gear and bearing life, Max Gear provides superior corrosion protection over competing conventional and synthetic gear oils.

Max Gear is available in the following viscosities: 75W-90, 75W-140, 80W-90, 85W-140 and SAE 90
The above product line is from Royal Purple and is a synthetic product. It is not cheap but should work well in a Corvair manual transaxle.

75W-90 Long Life Synthetic Gear Lube

Use AMSOIL Long Life Synthetic Gear Lube in differentials, manual transmissions or other gear applications where one or more of the following standards are specified: API GL-5 & MT-1, MIL-PRF-2105E, Dana* SHAES* 234 (Formerly Eaton* PS-037) for 250,000 miles, Dana SHAES 256 (Formerly Eaton PS-163) for 500,000 miles, Dana SHAES 429A, Mack* GO-J & GO-J+, Meritor* 0-76N (75W-90) & 0-80 (80W-140) plus hypoid gear oil specifications from ZF TE-ML 07A and 08 foreign and domestic manufacturers such as GM*, Ford* and Daimler* Chrysler*. It can also be used in rear axles where API Service GL-4 lubricant is recommended.

So a non-synthetic GL-4 or some of the more-expensive synthetics, like Royal Purple, will do the job for you. The above material should help you to make a selection for your Corvair manual transaxle. Read the fine print carefully! As you can see, many modern products are GL-5, but not necessarily GL-4 for manual transmissions. Some GL-4 transmission lubes are not OK for hypoid differentials. Since the Corvair transaxle needs combine the two, many products will not work. I believe the Royal Purple synthetic gear lube is OK for the Corvair, but somewhat expensive.

With a manual transmission transaxle, the lubricant is shared between the transmission and the differential. The fluid level should be checked in both components, and should be filled up to the bottom of the threads in the fill plug holes. The capacities and recommended fluid type is shown in the specifications section of the Corvair Shop Manual, as shown below. Note that the 3-speed and 4-speed transmissions have a slightly different capacity. These capacities are from the 1965 Chassis Shop Manual, but they apply to earlier Corvairs as well. However, the transmission design changed in 1966, so the 1966-69 manual transmission has a slightly different capacity.

1961-1965 FOUR-SPEED Manual transmission fill plug is circled in black. The DETENT SPRING CAP is circled in RED...




The link below will provide you with a list of useful websites that are Corvair-related. Some of the links will lead you to an extensive technical library that will allow you to download shop manuals and other technical references in Adobe Reader (.pdf) format at no cost. There is also a link that will help you to locate nearby CORSA (Corvair Society of America) club chapters. While the Corvair Forum can be very helpful as you work on your Corvair, having local friends and contacts in your region who are knowledgeable about the Corvair can also be very helpful. These family-friendly CORSA club chapters often offer picnics, group scenic drives, technical training and assistance, car shows, and competition events that can greatly enhance your enjoyment of Corvair ownership. You will also find a list of essential Corvair parts suppliers.

Common and Useful Corvair Websites

viewtopic.php?f=225&t=6007

[Jims_Corvair]

Thank you very much for the level of detail. I can already tell that I'm gonna love this forum.

Sent from my Nokia 6.1 using Corvair Forum mobile app

[Jims_Corvair]

The square plug you note is the fill location. a 5/8 open wrench often fits this. a better choice I think ( I do not remember for sure as I go to the tool box and grab a socket that fits) is a 12 point 11/32" socket. With the car level you remove the plug and fill with gear oil until it rubs out some. let drain until it is done running out and re-install the plug as the transaxle is full, and yes trans and diff share fluid.

The correct fluid is SAE 80W/90 GL3 (you should know this from your GM Corvair Shop Manual...if you do not have them get them ...you need the 1961 Corvair Shop Manual and the 64 Corvair Shop Manual Suppolement...you can buy hard copies at Clark's Corvair Parts or you can see PDF's here: https://www.corvair.org/chapters/corvan ... .php#C95RP ). That's said SAE 80W/90 GL3 is obsolete but SAE 80W/90 or 85W/90 GL4 can be found and should be used. DO NOT use any gear oil specced for GL5 (this is the most common and can be found everywhere but will ruin the transmission synchronizers over time. If is says GL5 on it at all do not use it. I have been using this product Sta-lube 85W90 GL4 successfully for years now https://www.amazon.com/CRC-Sta-Lube-SL2 ... B000M8RYMC . This is just the first link I found to the product and may not be the best place to order some...shop it.

I purchased this brand before I asked about the fill plug. Does anyone have any experience using this brand?

It was 4.x stars on Amazon.

Thanks
Jim

Sent from my Nokia 6.1 using Corvair Forum mobile app

[Jims_Corvair]

The square plug you note is the fill location. a 5/8 open wrench often fits this. a better choice I think ( I do not remember for sure as I go to the tool box and grab a socket that fits) is a 12 point 11/32" socket. With the car level you remove the plug and fill with gear oil until it runs out some. let drain until it is done running out and re-install the plug as the transaxle is full, and yes trans and diff share fluid.

The correct fluid is SAE 80W/90 GL3 (you should know this from your GM Corvair Shop Manual...if you do not have them get them ...you need the 1961 Corvair Shop Manual and the 64 Corvair Shop Manual Suppolement...you can buy hard copies at Clark's Corvair Parts or you can see PDF's here: https://www.corvair.org/chapters/corvan ... .php#C95RP ). That's said SAE 80W/90 GL3 is obsolete but SAE 80W/90 or 85W/90 GL4 can be found and should be used. DO NOT use any gear oil specced for GL5 (this is the most common and can be found everywhere but will ruin the transmission synchronizers over time. If is says GL5 on it at all do not use it. I have been using this product Sta-lube 85W90 GL4 successfully for years now https://www.amazon.com/CRC-Sta-Lube-SL2 ... B000M8RYMC . This is just the first link I found to the product and may not be the best place to order some...shop it.

I purchased this brand before I asked about the fill plug. Does anyone have any experience using this brand?

It was 4.x stars on Amazon.

Thanks
Jim

Sent from my Nokia 6.1 using Corvair Forum mobile app

Double tap

Sent from my Nokia 6.1 using Corvair Forum mobile app

[joelsplace]

That should be perfect.

[terribleted]

Should be fine.

[bbodie52]

VP Racing Fuels Hi Performance Classic GL-4 Gear Oil, Quart SAE 80W-90
Currently unavailable at Amazon.com
Available at manufacturer's website for $9.65/qt. Also listed from many other local sources at manufacturer's website.
https://vpracingfuels.com/product/vp-cl ... -90/?c=263




CRC 24239 Multi-Purpose Gear Oil, SAE-Gallon, 128 Fluid_Ounces
Price: $28.99/gallon or $13.95/qt. at Amazon.com
https://www.amazon.com/CRC-Sta-Lube-SL2 ... VF0GE4ZTJA




Price: $21.04/qt. at Amazon.com
https://www.amazon.com/Royal-Purple-ROY ... 133&sr=8-1

Price: $21.04/qt.

MAX GEAR – HIGH PERFORMANCE SYNTHETIC GEAR OIL
Max Gear is recommended for use in truck and automotive front or rear differentials, manual transmissions and lower gear units of marine engines that specify use of an API GL-5 or GL-4 fluid. It is non-corrosive to soft yellow metals (brass, bronze, copper, etc.) and synchronizer safe. Specially designed to extend gear and bearing life, Max Gear provides superior corrosion protection over competing conventional and synthetic gear oils.