Man. Trans Fluid
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Mountain Pass
Joined: Mar 2004
Posts: 111
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From: Jackson
Man. Trans Fluid
I gota work on my buddys 91 F-150 L6. He wants to chang the tranny fluid. Its 5 speed man, and the truck has over 150000 miles, I heard you don't have to change the fluid in a man. trans. Should I change It?
Senior User
Joined: Feb 2004
Posts: 250
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From: Nanticoke
A lot of people suggest using a heavy weight oil if its worn or old, but I had 140k on mine and the fluid came out ATF and was still red(never changed). I just put pennzoil syn blend back in, It sure did shift a lot smoother, and maybe even some better gas mileage, maybe. Hard part is getting the fluid in there. I ended up using a dish soap bottle with the little pull out spout and refilling it battle by bottle.
Temporarily Deactivated
Joined: Aug 2003
Posts: 1,859
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If the tranny is good spring the bucks for synthetic oil and it will probably last the life of the truck and shift much better in cold weather.
Put some hose on the oil bottle to squirt the oil in the tranny.
Put some hose on the oil bottle to squirt the oil in the tranny.
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Elder User
Joined: May 2003
Posts: 530
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From: Harrisonburg, VA
no 80w90.... unless you want to screw it up. Use mercon 3 atf fluid. I just changed mine about a month ago. 95 F150 4wd M5od tranny and I used valvoline mercon 3, that was the best that advance had here. Theres two plugs on the side of the tranny, I'm thinking they're 24mm that sounds right. Take the upper one out, place a drain pan under the truck, make sure you don't have right under the hole cause that stuff will come out in force, under the door might be a good place to start. It's not anything like when motor oil comes out so be warned. Take the bottom plug out and make sure you get the washer with it. Let it all drain and put the bottom plug in, Now you'll need a pump to get the new mercon 3 atf fluid in the upper hole, I thinking it takes like 7-8 quarts, pump enough in to where the fluid just starts comming out of the home, but the plug back in and drive away happy 
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Joined: Dec 2003
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A gear lube quart cap threads right onto a quart bottle of mercon/dexron III and with a 3" piece of hose works just fine. It will take about 4 quarts and if you want to be really cool you could use Mercon V, a synthetic version of mercon/dexron III.
