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Jan 20, 2023 | 10:03 AM

runninvtec

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Transmission

I have a 1989 F150 XLT Lariat with a 351w EFI. I currently have a C6 3AT transmission in it. I want to replace it with something a little better. I have been reading up and someone said a E4OD was a good replacement, especially being a successor to the C6 and having overdrive. Would the E4 be a plug n' play or would I have to make any modificatioons? Thx.

Jan 20, 2023 | 10:38 AM

Prototypemech

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From: Mojave, Ca

Lots of modifications. The C6 is a purely mechanical transmission. The E4OD is electronically controlled. You'll need a New wiring harness, new computer, new shifter stalk, new drive shaft, new torque converter. It's not impossible, but it'll take you a while so get the new transmission integrated in your truck.
Make sure you get the small block variety to fit your 5.8, the diesel and big-block transmission bell housings won't fit your small block engine.

Jan 20, 2023 | 10:51 AM

runninvtec

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is there another mechanical transmission i can replace the C6 with that has O/D? Since I have to replace the C6 anyway, I wanted to see if I could find something that would fit about the same way. Not necessarily plug n' play, but easily enough to where I don't have to drop thousands into it.

Jan 20, 2023 | 11:47 AM

Prototypemech

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You could swap it out for a manual transmission 5 speed, or keep the C6 transmission and add an aftermarket overdrive unit like a gear-vendor splitter. But it's still gunna be $$$.

Jan 20, 2023 | 01:04 PM

85e150

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An AOD will work but it's a weak transmission. Find one from a V8 truck from model years '88-'93. Ford fixed many of the problems along the way and those years are the "best".

The C6 is longer so you'll have to relocate the mount and have the driveshaft modified.

https://transmissioncenter.net/shop/...-measurements/

The later version of the AOD is the 4R70w or 4R75--they are stronger than the AOD and require a stand alone controller..

There is also a stand alone controller for the E4OD.

The E4OD is a LARGE transmission and the AOD etc will be easier to fit.

As mentioned, the GV unit is north of $3000, which may make sense depending on what you buy for a transmission and if you need a controller.

There is no free lunch. You might save gas, you might not save money.

Feb 2, 2023 | 10:24 AM

runninvtec

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Transmission Question

Okay so I have been told that the 302 and the 351 have the same bolt pattern for the transmissions. Would the Mazda 5-spd manual or the Ford 4-spd auto from the 302 fit? The year of my truck is 1989 and I have an EFI 351w. Thank you. I know I have a C6 and that typically it is longer than the other transmissions, I am prepared to buy the parts I need to get another transmission to work with my truck.

Feb 2, 2023 | 10:35 AM

My4Fordtrucks

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Yes. The 300, 302 and 351W are the same bell housing bolt pattern.

An AOD would be fine but was never behind a 351 so no telling how long it would last. The E4OD would need a a computer to control it.

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Feb 2, 2023 | 10:50 AM

My4Fordtrucks

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You can buy upgraded AOD transmissions to handle the extra power. It all depends on how much you want to spend.

Feb 2, 2023 | 11:25 AM

#10

Mikulh

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From: Laurel, MS

When I swapped from a 300 I-6 to 351W V8 I kept the Mazda 5-speed that was behind my 300 and I've been running it for 2 years as a daily driver behind the 351W.
So far, so good... but I don't tow much.

Feb 2, 2023 | 01:22 PM

#11

85e150

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Threads merged. Not sure why op opened a second thread asking the same questions.

Related thread:

https://www.ford-trucks.com/forums/1...-rear-end.html

Feb 2, 2023 | 02:28 PM

#12

jas88

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From: Greater Austin, Texas

If it was mine, I would put in a ZF5 manual trans.

Feb 2, 2023 | 04:48 PM

#13

My4Fordtrucks

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Quote:

Originally Posted by 85e150

Threads merged. Not sure why op opened a second thread asking the same questions.

Related thread:

https://www.ford-trucks.com/forums/1...-rear-end.html

I was wondering how my answer moved down from being the second post.

Feb 2, 2023 | 05:18 PM

#14

rla2005

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From: Kentucky

An AOD should be fine behind a 351W as long as the owner does not overload the vehicle or drive like "Mayhem" from the TV commercials. A shift kit will make the shifts firmer and potentially prevent any issues from those long/soft shifts the AOD tends to have. Just be sure to use the correct flexplate for a 351W/AOD combination. I believe the Crown Vic had the 351W/AOD from the factory.