Low transmission fluid
Thread Starter
Safety Car
Joined: Oct 2007
Posts: 4,426
Likes: 229
From: Pennsylvania
Low transmission fluid
Do you think I can drive my 85 4+3 Doug Nash Overdrive about 10 miles with the overdrive switch turned off because it will be about 1/2 quart low of fluid since I just put in an all-aluminum radiator? The cooler in the new tank is empty because it's brand new. Will it be safe to drive it that far while low on ATF fluid so I can get the overdrive serviced and completely filled to the radiator ATF cooling tank?
Drifting
Joined: Sep 2022
Posts: 1,456
Likes: 380
From: Liberty, SC
2023 C4 of the Year Finalist - Unmodified
Remember the oil is also a coolant for the gears and the pump itself. The pump will be 'running' the entire time so heat in it is a concern.
My theory would be that since you're not going to let the OD engage, you may be OK. But the parts for a 4+3 are hard to come by.
PM me if/when you need a new pump for one
My theory would be that since you're not going to let the OD engage, you may be OK. But the parts for a 4+3 are hard to come by.
PM me if/when you need a new pump for one
Oil Producer
Joined: Apr 2014
Posts: 9,365
Likes: 2,735
Do you think I can drive my 85 4+3 Doug Nash Overdrive about 10 miles with the overdrive switch turned off because it will be about 1/2 quart low of fluid since I just put in an all-aluminum radiator? The cooler in the new tank is empty because it's brand new. Will it be safe to drive it that far while low on ATF fluid so I can get the overdrive serviced and completely filled to the radiator ATF cooling tank?
up at the front, passenger side, on the radiator, below the rad cap, is the sending and return libe for the OD unit. I cant remember which line is which. but i pull the rubber off the metal tube and inject a half litre of dino atf every time i do a 4+3.
i use a big syringe i got from amazon. if u could find atf in the lucas type bottles or bags with the tips u could inject that way too
Thread Starter
Safety Car
Joined: Oct 2007
Posts: 4,426
Likes: 229
From: Pennsylvania
UPDATE! I just drove it around the streets where I live. About 3-4 miles. The 4-speed manual transmission shifted perfectly, and the OVERDRIVE ENGAGED dash light and transmission also worked fine. Nothing strange. I asked my mechanic and he felt it would be fine if I just drive it normally to his shop 10 miles away. I won't use the Overdrive to go there. Going to get a new fluid and filter (screen) service done. BTW....I sent the Chinese eBay all aluminum radiator back. It leaked like CRAZY! I put a completely stock one back in. NO LEAKS! 
Thread Starter
Safety Car
Joined: Oct 2007
Posts: 4,426
Likes: 229
From: Pennsylvania
Hey VikingTrad3r ..... I thought about doing that. I was worried about overfilling the system. That could be worse than being low on fluid.
Last edited by FOURSPEEDVETTE; Feb 28, 2026 at 08:18 PM. Reason: typo
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