Manual transmission fluid??

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Nov 1, 2023 | 06:52 PM

#61

TO_Vette

Racer

Joined: Aug 2006

Posts: 307

Likes: 4

From: Thousand Oaks Calif.

I have a quick question regarding your previous response. If I understand correctly, you are using Mobil 1 75W-90 for your manual transmission. Are you also using the same oil for your rear end? If not, then what?

I'm in the process of replacing fluids in my stock 1981 vehicle, both for the manual 4-speed transmission and the rear end. After reading through various posts, it's challenging to determine the right choice. I would prefer to use synthetic oil, but it seems that might not be the best option. Additionally, finding conventional oil has proven to be a bit difficult.

Thank you in advance for your assistance.

Nov 1, 2023 | 07:03 PM

#62

68post

Burning Brakes

Joined: Nov 2012

Posts: 788

Likes: 100

From: Indianapolis IN

Mobil 1 75w-90 is an excellent transmission fluid choice also. I've used it in the past and confirmed its use with the Allison engineer that did the durability testing on the 1983 SM465 transmission.
Your trans is no different in that regards. 75W-90 is equal to 30 weight engine oil at temperature.

Nov 1, 2023 | 07:17 PM

#63

MelWff

Race Director

Joined: May 2006

Posts: 18,742

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Quote:

Originally Posted by TO_Vette

No noises like that. To ask one more question, what do you run in the manual transmission?

Post 57 I stated both transmission and differential providing the bottle states for limited slip differentials.

Nov 1, 2023 | 07:34 PM

#64

TO_Vette

Racer

Joined: Aug 2006

Posts: 307

Likes: 4

From: Thousand Oaks Calif.

Moble 1 Synthetic correct?
Also, do you use that in the Rear end Also?

Nov 1, 2023 | 07:38 PM

#65

MelWff

Race Director

Joined: May 2006

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Quote:

Originally Posted by TO_Vette

Moble 1 Synthetic correct?
Also, do you use that in the Rear end Also?

I would only use a conventional gear oil suitable for limited slip differentials

Nov 2, 2023 | 09:21 AM

#66

TO_Vette

Racer

Joined: Aug 2006

Posts: 307

Likes: 4

From: Thousand Oaks Calif.

Is Luqui Moly worth using and should I use it both the rear end and transmission?

Nov 2, 2023 | 09:48 AM

#67

MelWff

Race Director

Joined: May 2006

Posts: 18,742

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Quote:

Originally Posted by TO_Vette

Is Luqui Moly worth using and should I use it both the rear end and transmission?

Nooo! Where are you getting these ideas?? Use 75W90 conventional gear oil for both differential and transmission with 2 bottles of GM additive. Nothing else.
https://shop.valvolineglobal.com/pro...hoC3rEQAvD_BwE