Things I learned from completing a differential swap myself

[AEF42]

Jared
Did you change out the pinion flange?
If so do you happen to remember the pre-load torque?
The reason I ask is because I just had a shop do mine and I’m sure they didn’t do it
correct and now I have no way of knowing
what my pre-load was....
I know they vary but at least I will have some idea of what it should be around.

 

[Jared_J]

Jared
Did you change out the pinion flange?
If so do you happen to remember the pre-load torque?
The reason I ask is because I just had a shop do mine and I’m sure they didn’t do it
correct and now I have no way of knowing
what my pre-load was....
I know they vary but at least I will have some idea of what it should be around.

Mine is factory loaded with auto pinion flange. I bought it from a salvage yard.

 

[fordguys550]

Man, thanks for doing this. Ive had 373s in my car for iver a year now and havnt done the bcm thing. Kinda wondering if its really hurting power. And if it is..wjat method is it using to pull power..?? I might have to pick your brain once i get my firscan licence.

 

[Jared_J]

Man, thanks for doing this. Ive had 373s in my car for iver a year now and havnt done the bcm thing. Kinda wondering if its really hurting power. And if it is..wjat method is it using to pull power..?? I might have to pick your brain once i get my firscan licence.

BCM change is needed for auto transmission to correct the shift management. Since you have MT, you don't really need it as I remember.

 

[Nagare]

^ what he said. Also, it really is pretty easy to do a change. Change the couple of numbers on the line, hit write, hit yes to confirm the changes, done.

 

[fordguys550]

So MT guys dont really need to do it?

 

[fordguys550]

I went ahead and ordered the scan tool. I still need to get my forscan license tho

 

[Jared_J]

So MT guys dont really need to do it?

The engine doesn't know when you are going to shift anyway, so it doesn't need to synchronize engine torque with shifting for smoothness. Also clutch slip is controlled by you not by the computer, and thus doesn't need a feedback of shaft output speed.
But it doesn't mean there won't exist any other engine control strategies using axle speed. Can be safer if you correct the BCM anyway.

 

[Atticaz]

I know this is a very old post. But, my info is relevant regarding you saying how difficult it would be to only use a floor jack to get the diff up in place....

I actually took on that challenge last weekend and was able to do it. It WAS super hard. But, I had no other way to get it up there. It 'IS' doable. But, It is PRETTY DANGEROUS and quite a workout, to do alone. If this method is a must, have a 2nd set of hands to help.

I weigh about 160 and it took every ounce of energy and sheer will, to get it up there without dropping it. NOT FUN.

Thank you for this post, by the way. I needed it to flash the correct gear ratio.

 

[Atticaz]

My swap is done. I did a ton of research, using this forum and used FORScan to put in the proper values.

726-12-01: 0163 0856 5527

0163 = 3.55 gears

0826 = 255/40r19 tires

55XX = specific to S550 V6

XX27 = Check sum

So quick question to you Automatic guys that have done this..... At what speed does you car shift into 6th gear, when just cruising? Mine is at 40MPH. Just checking to see if everything went well.

 

[ctandc72]

Really? I didn't think it was that bad using a GOOD floor jack. I've done it twice, both by myself. I simply placed the floor jack under the pumpkin, jacked it up so it took some of the weight off the bolts, loosened / removed the diff bolts then lowered it down.

 

[Atticaz]

Really? I didn't think it was that bad using a GOOD floor jack. I've done it twice, both by myself. I simply placed the floor jack under the pumpkin, jacked it up so it took some of the weight off the bolts, loosened / removed the diff bolts then lowered it down.

Lowering it was cake. It was getting the new one up. My jack has a smaller saddle. It teetered a lot.