Best gear oil for 1985 Monte Carlo SS,

[killagt]

Hi I just bought 1985 Monte Carlo SS 87,000 Miles, the car is hardly drive and alway been park, I just bought it and want to do all the maintain I can, so what oils is recomment for tranny and rear diff, I want do it one and do it right, and never want to do it again, I will pay the price for high quality oils. thanks

 

[Toy4x4runner]

Valvoline Syn 75w-90. Get it at Napa.

 

[ChiTDI]

I used Redline at 80k no regrets, looking at 165k.

 

[ChiTDI]

Killagt - those trannies were susceptible to a failing solenoid switch that is a straightforward repair when dropping the trans pan and filter. I found the illustrated repair on a MoneCarlo forum. Hundred bucks for parts. Half hour of extra work, and I work slowly. Better than thousands at a shop or dealer. If you experience symptoms research before thinking the purchase was a bad one. Enjoy the V8.

 

[ChiTDI]

Couldn't believe I found this, if this your trans then...
http://www.montecarloss.com/TCC_Solenoid.html

 

[killagt]

OMG thanks, I havent had that problem yet, but that something I will look into ASAP. BTW since the car is old, should I stick with dino oil rather then synthetic, and change it like every 30K miles or so. thanks

 

[mechtech2]

kill - Change it every 30K??? WAY too long for any oil!
In general 3-5,000 miles for dino and 5 - 10,000 for synthetic. Many do go somewhat longer with good synthetic oil.

 

[Kestas]

mechtech, I think the topic is still on transmission and differential fluids.