4r70 to 4r100 swap

[KuntryKid]

what all is needed to do this swap? thanx for the help in advance

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[kaptain]

I just completed this a month ago on my truck, so I know everything you will need and be going through. From the get go Im going to warn you it is expensive. Now, the trucks that got a 4r100 from the factory where '99-'01 F150's with the 7700lb tow package. When you order parts, pick a year (such as 2000) and order the parts you need using this to look up by application. Your truck looks like a 4x4 so make sure you also specify 4x4 when you order. This is what you will need:

a 4r100 4x4 transmission
6 bolt flexplate (depending on transmission- some are set up for a 4 bolt, in wich case you will not need a new one)
transmission wiring harness
PCM
new transmission cooler line (if equiped)
new transmission cooler (if quiped- its the same as the one for the 4r70w but
fittings to adapt cooler lines to transmission (if equiped- dont have to be form ford, I got mine from the hardware store)
its a good idea to put in a new one)
two new speed sensors
neutral safety switch
shift cable
shift cable bracket
transmission crossmember
new skid plate for t-case
Indicator (dipstick) tube
indicator (dipstick)

If you still have torsion springs in the front, you will also need:
new torsion springs (you wont be able to look these up by application- you will need the part number which i have if you need them)
because the 4r100 is ~5" longer than the 4r70w, you will have to move the torsion spring crossmember back ~5". Some trucks already have the holes for relocating in the frame, some dont. If you dont, you will have to drill them.

Because of the length difference, you will also need to go to a driveline shop and have them lengthen the front prop shaft, and shorten the rear driveshaft. I would have them measure for this once the transmission is installed.

Your exhaust crossove will also need to be move back about 5" to accomidate the new tranny. This is a job for a local exhaust shop, as it requires some complicated bending and fitting, and should be done once everything is installed except for the t-case skidplate. I just cut the exhaust off 2" behind the 02 sensors and drove it to the exhaust shop with open pipes. This worked fine for me.

When you intall your new PCM you will have to have a ford tech hook up a computer and flash the instrument cluster to the PCM, as well as enter your keys to the PATS system. If you dont do this, the engine will turn over, but the PATS system will cut the ignition so it will not start.

The last thing I can think of is that depending on the year of your vehicle, you may be missing one wire in your main wiring harness. I spoke to one guy when I was doing my research who had a '97, and when he tried to drive the tranny didnt function properly because he was missing a wire to the PCM. He solved this be simply running that one wire from the tranny wiring harness connector to the PCM. I did not have this problem, and I suspect it is because my truck was made between '99 and '01 when the 4r100 was offered.

If I think of anything else, Ill let you know. If you have any more questions of need help as you go along, feel free to email me as I dont check here very consistently. You can email me by going to my user profile and clicking the link.

Hope that helps!

[kaptain]

one more thing- I thought you might want some idea of price for the total project. Here is roughly what it will cost:

parts I listed: ~$1700
Transmission: ~$400 (junkyard; car-part.com) - $2600 (Jasper; what I recomend, and what I bought)
driveshaft lengthen/shorten: ~$270 for both
Labor: ~$1300-$3000 (?) (this depends on labor rate, compitence of mechanic, # of issues along the way, and how much you do yourself)
exhaust work: ~$200- $600

While researching, one guy told me his total cost came out to about $10k. My total for the tranny swap was about $8600. Like I said, its not cheap.

[phil6608]

Kaptain did a good job on your list.
I also just had this done. There was a couple things that differed but most of it was the same.
I spent $5000 + shipping on my trany!($1000 was core deposit. Had nothing to send them) I tried to get one from my local junk yard and they were all 1000 bucks so I just said F it..lol
In the end it cost me between 8 and $8500.

Phil

[KuntryKid]

alright thanx guys. i guess ill start savin up again

[phil6608]

What diff gears and motor do you have?

Phil

[KuntryKid]

5.4 and 5.38s

[phil6608]

Originally Posted by KuntryKid

5.4 and 5.38s

With just a stock 5.4 you should be ok with a built up 4R70W(if that's what you have)And should cost less then half as much as swapping in a 4R100.
The only reason I went with a 4R100 is I'm pushing close to 600 RWHP and went throw 3 built 4R70Ws in 3 years!

Phil

[KuntryKid]

ive got a built one now and have already had to have it rebuilt once

[97on37s]

Well thats a lot of cash that I don't have. I got to do the same swap or eather I want to go 2 the 5r110

[KuntryKid]

my truck is too big and right foot is too heavy for the 4r70

[97on37s]

Originally Posted by KuntryKid

my truck is too big and right foot is too heavy for the 4r70

The 4r70 is a weak tranny to begain with. A stock truck with a 4.6 it would be fine.

[phil6608]

Originally Posted by KuntryKid

ive got a built one now and have already had to have it rebuilt once

I didn't know that.
Well then,,your thinking in the right direction with the 4R100 swap.

The 4R70W is junk in my opinion! Even built up it was costing me 2 to $2500 every year...lol. I had to do something.
So if the 4R100 last more then 3 years I'm ahead of the game.

Phil

[KuntryKid]

i paid 2000 and i had to take it back for a rebuild in 3 months

[kaptain]

LOL! I went through 4 4r70w's in three years on the N/A 5.4l. I agree that they are just too weak. When I started the L swap I didnt even consider a built 4r70w, I knew it would have to be a 4r100.