Real world results for Overdrive in an FE

[Racer Z]

Yeah the calculator is set up for 4X4's. You'd probably have to manually enter 1.0 for high and low range in the transfer case section for a 2wd vehicle.

I did. I think it's not set up to work with 11.5 It's setup to work with 37's which are close to the circumference of my 11.5

Rim diameter, aspect ratio and tread width are used to calculate the rolling circumference of the tire. Do this wrong and all your numbers mean squat.

[mlheppl]

you're right. I was entering in metric sizes when I was doing my truck. Seems like the info was consistent with other info i've been told/read.

[GSequoia]

A low first would be lovely. Even as a granny, I don't mind skipping first in most situations. For this truck towing ability comes first quickly followed by economy (which is why I'm not looking into AOD!).

I've seen an Overdrive unit that replaces the tailcone of a standard C6, I don't remember the name though. Has anybody seen this before?

[mlheppl]

It sounds like you're thinking of the gear vendors over/underdrive unit. http://www.gearvendors.com/f2wd3s.html.

[Racer Z]

My 50 Chevy had a 4-speed Granny Low. Normally I started in second. First was so low the I hit reline before halfway across an intersection, and then I was barely doing 5 mph. I've heard it referred to as "Parade Gear".

An electric tail-shaft OD would work just fine for the C6. Hmm.

[no_treble]

Advance Adapters also makes one: http://advanceadapters.com/category/21/Overdrives.html

Looks like a member here installed one of these about five years ago: http://www.fordification.com/forum/view ... ger#p29461

The write-up link in the thread is broken, but it's here: http://www.fordification.com/tech/torque-splitter.htm

[Racer Z]

I did a fair amount of searching today and everything kept pointing back to GearVendors.com

It is definitely the ticket for our FE blocks and C6. The other choices would be to convert to a manual tranny or to get a newer engine block that had a factory overdrive.

Until I can find an extra three grand or a used overdrive unit, I will leave it be.

[mlheppl]

I did a fair amount of searching today and everything kept pointing back to GearVendors.com

It is definitely the ticket for our FE blocks and C6. The other choices would be to convert to a manual tranny or to get a newer engine block that had a factory overdrive.

Until I can find an extra three grand or a used overdrive unit, I will leave it be.

I agree. 3 grand is too much for 2 to 3 mpg's. However if someone wanted to leave one on my doorstep, I'd take the time to install it.

[GSequoia]

I did a fair amount of searching today and everything kept pointing back to GearVendors.com

It is definitely the ticket for our FE blocks and C6. The other choices would be to convert to a manual tranny or to get a newer engine block that had a factory overdrive.

Until I can find an extra three grand or a used overdrive unit, I will leave it be.

I agree. 3 grand is too much for 2 to 3 mpg's. However if someone wanted to leave one on my doorstep, I'd take the time to install it.

Agreed times three.

If it works as they say it does it apperas to be a great product that I would love. Having the OD when needed and, more importantly, 2 1/2 gear on hills would be fantastic but not necessarily $3,000 of fantastic. For that I could probably get one of them six speeds and adapt it to an FE!

[Racer Z]

Awe heck, I put a $2000 long block in my truck and it's still worth less than the price of the motor. If I spent 3 grand on an AOD, that would not raise the value of my truck any.
It would however, give me bragging rights.

[j41385]

Awe heck, I put a $2000 long block in my truck and it's still worth less than the price of the motor. If I spent 3 grand on an AOD, that would not raise the value of my truck any.
It would however, give me bragging rights.

I bought my AOD from the junkyard as a runner for 220 dollars. Paid 70 dollars to my trans guy to go inside and look at it to see if it needed rebuilt, he said it had recently been rebuilt and they even put a shift kit in. 20 dollars from summit for a linkage corrector for my carb to hook to the throttle valve cable, and 75 dollars to have my drive line shortened. So for about $385 dollars I went from a c6 to an aod, and I have to admit I love the result.

The Transmission I bought apparently came from a Cash For Clunkers truck, it looked very nice, nothing wrong with it. So it's a shame, but I got something good from it. My dad god rid of his immaculate 89 4x4 5 speed ranger in that deal, a truck I grew up with. We are both torn up over that, but my mom has a new 09 vw passat.

Granted I realise this is about FE's but there is an option to get an AOD to hook to an FE if you check out Lentech.

[My427stang]

Love OD in my FE powered Mustang

However, you need to do some math to pick the right gear and box combo.

If running a manual transmission, you want to look at 1st gear and OD multiplied by your final drive.

Any lower than 12.25:1 (1st gear x rear axle) makes 1st gear very short and can be annoying.

Anything taller than 2.90:1 in OD (OD x rear axle) would make 5th only usable in real flat situations in a truck.

If running an AOD, focus on high gear more, 1st isn't as fussy, because it'll shift when it wants.

Here's a real world example of my Mustang, keep in mind, its 489 cid and makes a lot of torque, so my numbers allow a little taller rear axle gear than a truck would want.

ORIGINAL 5 SPEED BUILD
2.87 1st gear x 3.70 rear = 10.61:1 1st gear compound
.64 OD x 3.70 rear axle = 2.37 final drive compound in 5th

This setup was OK in town, but needed a little more low end at stoplights, 5th gear I found myself driving way too fast, and really didn't need to use it unless I was rocking along. In 5th it was too low of RPM at 70 mph to be efficient.

RECENT GEAR CHANGE
2.87 1st gear x 4.11 rear = 11.80:1 1st gear compound
.64 OD x 4.11 rear axle = 2.64 final drive compound in 5th

This setup is fantastic. 1st gear in town is nice, the motor doesn't have to work as hard and it doesn't feel like granny low. On the highway it raised my rpm by only 350 rpm at 75 mph, but I get better mileage.

If I went with 4.33 in the axle, 5th would still work well, but 1st starts getting short. Keep in mind this is a car, that 4.33 combo would probably work well in a heavier truck. Bottom line, be sure to do the math before you pick an OD/rear gear combo.

You also need to take tire size into account. Let's say you're running 245/60/15's on your mustang, and GSequoia is running 235/85/16's on his F250. The 235/85/16's have a 16" larger circumference. That is going to lower his rpm's considerably.

True, and worth noting, but look at the difference in the ratios I run with a 28 inch tall 275/60, I had accounted for that with the heavy truck recommendation. Should have mentioned it though