AOD tranny

1420 Views 15 Replies 9 Participants Last post by Thumper351, Oct 10, 2003

Thumper351

Discussion Starter · Oct 7, 2003

I have an 85 XLT 351 H.O. with the C-6 transmission. I was wondering if anyone has swapped an AOD tranny into this combo before. 9MPG city and 11.5 hwy is a little too low to take. If so, how difficult was it and what was needed to make it work right? Engine has an Eldebrock intake and carb w/cruise. Thanks for any help. Thanks for your responses about the mysterious steel top Broncs.

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rem_243

· #2 · Oct 7, 2003

I don't think swapping in the AOD will give you enough gas mileage to justify the swap. Just my $.02

Crazed

· #3 · Oct 7, 2003

Sorry...I think it will...probably 1 1/2 or 2 mpg. that would add up.

chux

· #4 · Oct 7, 2003

yeah i get like 13 HWY. i was wondering about that swap too.

http://www.superford.org/registry/vehicles/detail.php?id=1394

:usa

rem_243

· #5 · Oct 8, 2003

You mean you guys would go to the trouble of swapping a tranny for 1.5-2 MPG. :banghead :shrug :banghead :shrug :banghead

Ogeechee 4x4

· #6 · Oct 8, 2003

chux said:
yeah i get like 13 HWY. i was wondering about that swap too.

i get 13 hwy and i've got the E40D:banghead

Davids78Bronco

· #7 · Oct 8, 2003

rem_243 said:
You mean you guys would go to the trouble of swapping a tranny for 1.5-2 MPG. :banghead :shrug :banghead :shrug :banghead

Let's see... same size transmission (give, or take, 1/2"), 3hr's work, one extra gear, 1.5-2.5 mpg increase with a 25-33gl tank... Yeah, I would

rem_243

· #8 · Oct 8, 2003

Hey, I didn't mean to come across sarcastic, but I just didn't see the legitimacy for the swap with just those results. And there has been around five posts after the question (including my stupid one)and Thumper's questions still aren't answered. It's kind of frustrating to ask a question and get responses that don't answer your question. Hey my first post was stupid and didn't need to be posted, and so are alot of the other ones, your guy's forum space wouldn't be used up so rapidly if me and others don't reply to questions we don't know the answer for. My bad for starting the first stupid post.:brownbag

Fireguy50

· #9 · Oct 8, 2003

IT's all about the tranny AND diff gearing.

Most of the AOD trucks have and OD gear too high, so the truck boogs down, upshifts constantly, and sucks more gas.

If you change the tranny, make the rear gearing higher too.
Try to keep highway cruise at aprox 2500RPM

Fireguy50

· #10 · Oct 8, 2003

GO GET THE GEAR CALCULATOR IN THE TECH SECTION!
http://fullsizebronco.com/forum/showthread.php?s=&threadid=7228

Fireguy50

· #11 · Oct 8, 2003

If you have an AOD
1st = 2.400
2nd = 1.840
3rd = 1.000 (drive)
4th = 0.667 (OD or OverDrive)

Injected

· #12 · Oct 8, 2003

I just finished this swap on my '88 351 and am almost done with the write up on it, I also have a few pics of what I did. If you're interested let me know and I'll PM it to anyone who's interested.
I'm very happy with the swap, I did it to get my rpms lower at highway speeds and it worked out very well. With the C6 I was pushing [email protected], now it's [email protected]
The swap is not hard to do, give me a day or two and I'll have the write up done.
I say go for it, like I said before I'm very happy with the swap.

Greg

chux

· #13 · Oct 8, 2003

hey injected,
sounds like you got a winner. i'm interested!

http://www.superford.org/registry/vehicles/detail.php?id=1394

Andy351

· #14 · Oct 8, 2003

why anyone would want to swap out a c-6 for an AOD is beyond me. overdrive is over rated

Injected

· #15 · Oct 9, 2003

hey injected, sounds like you got a winner. i'm interested!

I should have it done by Saturday evening, I should have time to finish it by then.

why anyone would want to swap out a c-6 for an AOD is beyond me. overdrive is over rated

To each his own, we all do stuff to our rides for our own reasons. I wanted to save the wear and tear on my freshly built engine due to the higher rpms at highway speeds. Mine is a work truck that makes several 5hr plus trips up to the farm.
For mileage I'm not able to say how much of an increase it has been since I'm still working on fine-tuning my warmed over 351 setup. I can say this, I got 10mpg all the time before the swap. The first highway trip after the swap I netted 13.5, that's 3.5mpg and good enough for me to justify the swap. As soon as I get a good tune on the new engine I'll have more consistent numbers on the mileage increase. That's @ 73mph on a 250 mile trip each way, both legs of the trip were made on the same day.

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Thumper351

Discussion Starter · #16 · Oct 10, 2003

Thanks everyone for your comments. Greg- looking forward to your post. As to why bother, I live away from my family till the kid graduates and it's a $75 round trip to visit. More mpg, means more visits. Cost of swap will pay for itself in less then 1 year. Simple as that. This is a great site and I'm learning alot from everyones input.

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