Mazda SG-1

[cb_13]

I saw some of this for sale. Shows it’s a 75w85 GL4 rated lube. Would this be safe for an older synchronized manual transmission?

Transmission in question is an NP435. Calls for 80w90 or sae50 depending on vehicle it’s in and year range. Pretty sure mine calls for sae50.

 

[MolaKule]

You have a number of options:

An 75W85 MTF would be a 12.0cSt@100C and SAE 75W85:

Redline MT-85

The next higher viscosity MTFs in the 14-16 cSt (SAE 75W90) range would be:

1. Amsoil MTG
2. Redline MT-90
3. Castrol Syntrans Multivehicle 75W-90
4. Castrol Syntrans Transaxle 75w-90
5. Ford XT-75W90-QGT (Carries a GL-5 rating as well)
6. Ford MOTORCRAFT® Full Synthetic Manual Transmission FluidXT-M5-QS
7. ACDelco 10-4059 GL-4 75W-90 Manual Transmission Fluid
8. RAVENOL TSG SAE 75W-9
9. LIQUIMOLY 75W-90 GL4
10. PENNZOIL 75W90 GL-4
11. Motul MotylGEAR 300 GL-4/GL-5

Let me state this again: Before changing an MTF in a vehicle, obtain an OEM fluid sample and post the analysis in
Gear& Transmission Used/Virgin Oil Analysis

Virgin and Used Gear & Transmission Analysis reports.

bobistheoilguy.com

so we can attempt to suggest a fluid of similar viscosity and additive signature. This removes a lot of guesswork on your part.

 

[pbm]

Where are you seeing the SG-1 for sale and for how much? Our CX-30 calls for it in the rear diff and the front
transfer case. I used Royal Purple 75w90 in the rear diff but couldn't change the front transfer case lube because the fill hole is blocked. The RP is rated for both GL4 and GL5 and seems to be working fine.

 

[cb_13]

Let me state this again: Before changing an MTF in a vehicle, obtain an OEM fluid sample and post the analysis in
Gear& Transmission Used/Virgin Oil Analysis

Virgin and Used Gear & Transmission Analysis reports.

bobistheoilguy.com

so we can attempt to suggest a fluid of similar viscosity and additive signature. This removes a lot of guesswork on your part.

I would hope that a modern lube would be much improved over one that was originally spec’s in the 60s. I’m not gonna have any oem fluid to compare to. I’d assume this thing currently has 80w90 gl5 in it. Shouldn’t be an issue if it’s been rebuilt with the aluminum synchros like I’ve seen in rebuild kits or came standard but I didn’t do the rebuild so I’m just trying to be safe.

There’s a few specialty fluids like Brad Penn GL4 that look to be specifically made for my situation. About as “advanced” as the stuff from the 60s but shouldn’t cause any damage.

Where are you seeing the SG-1 for sale and for how much? Our CX-30 calls for it in the rear diff and the front
transfer case. I used Royal Purple 75w90 in the rear diff but couldn't change the front transfer case lube because the fill hole is blocked. The RP is rated for both GL4 and GL5 and seems to be working fine.

eBay it’s about $4/qt after shipping.

 

[pbm]

eBay it’s about $4/qt after shipping.

I'm seeing it for $31 to $45 a quart on Ebay. If you can get it for $4 buy all you can and sell it on Mazda forums for $20 a quart.

PS: The Royal Purple should work well for you.

 

[cb_13]

I'm seeing it for $31 to $45 a quart on Ebay. If you can get it for $4 buy all you can and sell it on Mazda forums for $20 a quart.

PS: The Royal Purple should work well for you.

Looks like it’s gained a bunch of watchers so someone is probably gonna run the price up right at the end

Still might be a deal for someone that could use it. https://www.ebay.com/itm/1158605364...08i2sIRTHG&var=&widget_ver=artemis&media=COPY