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rear diff VENT?

do our cars have a vent for the rear diff like most other rear diff's do?


reason i ask is this,,

on my build i am doing a mod to the rear cover.

the rear cover will integrate a drain plug and a fill plug.

i wanted to know if i can get away with a rubber "pop in" plug to serve as the fill.

reasons for this are obvious to anyone who's done rear diff oil changes before. 

you have more clearance to "add" oil from the rear of the diff tipping a bottle of gear oil in,, and why not have a drain plug as well.

is the rear diff under pressure from heat and such? I assume yes but not like its a lot.,,, since i see no vent at all anywhere... nothing mentioned about a vent in the shop drive train manuals either.

rear diff VENT?

Reply #1
Look on top of the axle tubes. The 7.5" rear shows it on the passenger side.

rear diff VENT?

Reply #2
The rear does have heat in it, but there shouldn't really be any pressure. It users splashing to lube up tye gear. Everything else is lubed up by the oil in the axle tubes.
Quote from: jcassity
I honestly dont think you could exceed the cost of a new car buy installing new *stock* parts everywhere in your coug our tbird. Its just plain impossible. You could revamp the entire drivetrain/engine/suspenstion and still come out ahead.
Hooligans! 
1988 Crown Vic wagon. 120K California car. Wifes grocery getter. (junked)
1987 Ford Thunderbird LX. 5.0. s.o., sn-95 t-5 and an f-150 clutch. Driven daily and going strong.
1986 cougar.
lilsammywasapunkrocker@yahoo.com

rear diff VENT?

Reply #3
I seem to recall a little vent cap thingy in the axle tube, top side.
Mike

rear diff VENT?

Reply #4
They use the vent to bolt the rubber line from the body to the axle. My ol 92 dakota has a pop in rubber plug on the diff cover on the mopar 8.25 and I will say the rear definitely needs vented or after a long trip you'll pop a pinion seal or axle end seal.

rear diff VENT?

Reply #5
looked at the vent on the axle tube,, seems to integrate a axle vent as mentioned along with a brass block to split one brake line into 2 ....

so yes thats where the vent is.

rear diff VENT?

Reply #6
The vent on my 8.8 is on the passenger side top towards the wheel. I replaced my differential cover a while back used a B&M cover I found on ebay. Only problem I had was getting stupid. The cover has a drain and fill plug but I forgot about the fill plug on the drivers side front of the differential. Filled the rear end using the fill plug on the cover as a gauge. Took the car for a drive and was smelling gear oil. Parked it and I had gear oil all over the gas tank cover. Then I remembered the fill plug on the differential which is quite a bit lower than the one on the new cover. Drained about a half quart been good since. Felt like an idiot.
1987 Turbo Coupe, 306, Trick Flow Track Heat heads, Comp Cam, Trick Flow Pistons, Eagle Rods, Center Force clutch, T-5, 8.8 w/373 gears, and a bunch more

rear diff VENT?

Reply #7
Quote from: tommym;465946
The vent on my 8.8 is on the passenger side top towards the wheel.

Yup. Same place on the 7.5 as well. Looks like this: https://lmr.com/item/LRS-4022A/86-04-Mustang-88-Rear-Axle-Housing-Vent
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.