Need Some Rearend help/info

[Twitch]

Originally Posted by ASH302

I am blown away with this information about the stock mach diff. Just blows me away and why Ford would not have replacement parts or anyone just blows me away.
My rear end isn't stock so i'm not worried about it, but feel bad for you and others out there with the stock diff.

ASh

My cousin says that this is starting to become more of the norm for car manufacturers. They say its cheaper or about the same price to replace the entire diff unit than to rebuild after you count all parts and labor so in the end its just easier.

I can kind of see the point but for some that just need a specific part to get things back in order, that ends up not being true for DIY'er.

Guess If im going to replace the diff then I'll just upgrade the rear to a 31 spline mainly cause aftermarket parts are more plentiful for the 31 spline 8.8 after all my research.

I dont get why Ford went kinda weird on the Mach. Couple yrs back I couldnt get an alternator anywhere. Ford dealer,Napa, and another place ordered me a new one and it would not fit, none had the shaker mount holes on them. All ford did was get a Cobra one, didnt work,holes didnt line up. Just had original rebuilt nearby been good since.

[ASH302]

yea that is crazy.
Honestly if you can swing it get the built one.
on my 04 I did the Cobra diff and 31 spline, but kept stock gears.

my 03 came with the rear built with 4.10s, it is a whole other animal on the street.

ASh

[Twitch]

Originally Posted by ASH302

yea that is crazy.
Honestly if you can swing it get the built one.
on my 04 I did the Cobra diff and 31 spline, but kept stock gears.

my 03 came with the rear built with 4.10s, it is a whole other animal on the street.

ASh

Yea mine came with stock diff. But took the car into local ford for a warranty repair. They said rear diff bearings were bad which I highly doubted but figured hey, new bearings installed for free.
Get car back and 2 months later bad sounds in rear, ford said whoever I had do work on the rear installed it wrong and it somehow trashed the whole rear....lol.

I told them they did the work...lol.
But get this. I get the car back after the new rear was done,kept driving around and getting passed by everyone. My speedo was 10 mph off.
Told Ford they put wrong gears in, fix my speedo.

They wouldnt without proof but wanted to charge me $100 to open rearend and look...NOPE. Showed them proof that they somehow installed 4.10's..

So free 4.10's and then they paid for the FRPP Speed-Cal box...lol

Same Ford dealer that ruined 2 engines in my dads truck over a 2 week period, no joke. 1st motor they left a tool somewhere between the tranny and motor and it knocked a hole in the block.Week later a new motor and they cracked the block near the head. So motor 3 was the charm...lol

[ASH302]

I think I would try a different Ford dealership, lol.
I'm in Willis and a big Ford dealership a few exits up, I will not use them for service type stuff. I drive all the way to Huntsville to have all work done.
4.10s are fun, but not, depends which way i'm driving. I think I would like 3.73.
For sure don't like 4.10s on the hwy while cruising.

ASh

[Twitch]

Yeah I dont use them. I only did yrs back just cause of the warranty I got with the car.
Believe or not thats just the worst stuff they have done. Dad took same truck in that they blew the motors to get oil change and tire rotation, he got about half mile down the road and rear wheel fell off.
After that he got rid of the truck, figured it was a sign...lol

As for the 4.10's,when I do the diff I may drop down to 3.73's. 4.10's are fun but my gas mileage took a beating. With the 3.55's I drove to Dallas and back and averaged about 27mpg, now its more like 22 and a lot of changing gears.

[DSG2003Mach1]

Originally Posted by Twitch

The same here, I couldnt believe Ford did that. I would have at least thought an aftermarket company would have had something but no luck and if there is no one knows what part number it is to even try ordering.

It just sucks I have to buy the entire carrier setup since the diff has new bearings and seals, thats how I found out about the 2 chipped teeth on the spider gear. But since I cant find any part for it I put it back together for time being and thats been 2 months ago now....lol.

Its really not bad, I cant tell by driving it,makes no noise,no whine or popping at all. Backlash is in spec.

Is the trutrac a noisy rear?
Ive heard that you can hear the posi engage if I remember correct about the one I was reading about.

I have a procharger with a BRRV and full exhaust, if it makes noises its not enough to hear over all that. I do have a bit of a thumping sound on decel sometimes but thats about it

[Twitch]

Originally Posted by DSG2003Mach1

I have a procharger with a BRRV and full exhaust, if it makes noises its not enough to hear over all that. I do have a bit of a thumping sound on decel sometimes but thats about it

Thanks for the info.
Prob gonna do the whole diff change out/upgrade next month. Got a good deal on a set of FR500 9" wheels and 275 tires from AM I couldnt pass up, just under $1000 mounted and shipped. Calling them is much cheaper than just online order, always get better deals. Discount tire quoted me $1500 for the exact same setup.

Hopefully the diff dont go boom in the meantime...lol. Doubt it,like I said I wouldnt have even known if I wasnt in there doing carrier/axle bearings and seals. Its just knowing couple chipped spider teeth bugs me.

[Twitch]

Finally figured out the profile avatar,lol kept telling me upload failed.

[ASH302]

Originally Posted by Twitch

Finally figured out the profile avatar,lol kept telling me upload failed.

LOL,

ASh

[mikeracing]

Originally Posted by ASH302

I am blown away with this information about the stock mach diff. Just blows me away and why Ford would not have replacement parts or anyone just blows me away.
My rear end isn't stock so i'm not worried about it, but feel bad for you and others out there with the stock diff.

ASh

The only reason any car manufacturer sales parts for more than a few years old is because they are required too by law. If memory serves they have to sell parts for 10 years after manufacture.

[Twitch]

Originally Posted by mikeracing

The only reason any car manufacturer sales parts for more than a few years old is because they are required too by law. If memory serves they have to sell parts for 10 years after manufacture.

I knew that but you cant even buy them aftermarket. Ford 8.8 is still the same old ford 8.8 being used for years its just Ford changed something on the carrier for the mach that cant make any other 8.8 spider gears work.

Im done with it, about to either get the Eaton Truetrac or Yukon Duragrip and be done. Sometime this month hopefully. Probably gonna replace the ring and pinion too just to have it all done and good to go. Install isnt costing me anything. Just gonna take it to my cousins speed shop in Austin and me and him get it done.