The joke among guys is if your car is making a strange or irritating noise, turn the radio up. But there are some noises you just shouldn't ignore, and the whine coming from the pump area of the 4R70W Ford overdrive transmission in our ex-Santa Barbara County Sheriff's '03 Crown Victoria would surely leave us stranded by the roadside if we took that advice.
We were expecting a bad stator bearing in the torque converter but decided to have the whole transmission gone through just to be safe. Good thing, too. It was a mess in there. If you want to see what lots of hard miles do to any transmission, follow along as Leo Glassbrenner, owner of Remac Transmissions in San Dimas, California, performs a transmission rebuild on our severely worn 4R70W Ford overdrive transmission to severe duty specs. Chevy and Chrysler guys, read along. Even if you don't speak Ford, there is transmission rebuild information in this article that applies to any modern, electronically controlled transmission.
What's A 4R70W?
The 4R70W Ford Overdrive Transmission is an updated version of Ford's long-running AOD transmission that first appeared in the '80s. The nomenclature breaks down like this:
4 - Four forward speeds
R - Rear-wheel drive
70 - Torque rating x 10 (will hold 700 lb-ft)
Note: This rating is based on torque converter multiplication. It won't stand up to an engine that makes 700 lb-ft at the crank.
W - Wide ratio
Compare the gear ratios and you can see why the 4R earned its W designation. All 4Rs have the same gear ratios, by the way. There is no such thing as a non-W 4R70.
Ford Overdrive Transmission Applications
'93 to '98 Lincoln Mark VIII
'96 to '04 Ford Mustang
'94 to '97 Ford Thunderbird, Mercury Cougar
'95 to '04 Ford Crown Victoria, Mercury Grand Marquis
'93 to '04 Lincoln Town Car
'93 to '03 Ford F-series trucks
'97 to '04 Ford Expedition
'96 to '01 Ford Explorer, Mercury Mountaineer
AOD vs. 4R70W
While our transmission was strewn out before us on Glassbrenner's bench, he was able to show us the hard part differences among the 4R70W and its predecessors, the AOD and AOD-E. The differences are surprisingly few.
