How-to: Install 4:10 gears

[Jay Tee]

Hello people I am back with another do-it-yourselfer,The 4:10 gears install in my 2005 GT
Let me tell you that this is not for the week do-it-yourselfer, I had to borrow exter tools from friends (I had to borrow a ½” drive air impact gun and some sockets and a torque wrench and a pulley puller) it took me about 9 hours over a period of 5 days working for about an hour and a half each day. It was not rocket science but you do NEED TO VERY THOROUGH AND DILLAGENT if you should choose to accept the mission…
Ok now on to the fun

Gather up the tools and stuff you will need, like a pair of jack stands, a floor jack, wrenches and sockets and a ½” drive impact with a 1 and 1/16 socket and a torque wrench (pic 1) now I drove the car up onto some blocks (pic 2) once on the blocks I used some 4x6s to block the front wheels form rolling while I jacked up the back of the car.
Then place a pice of wood on the floor jack then roll it under the differential to jack it up
(pic 3) and now jack up to your desired height. For me it was about 18 high (pic 4)
Now look up under the car just behind the mufflers (axel backs) and you will see the sub frame of the car (pic 5) that’s where you will put the jack stand at..

[Jay Tee]

Now position the jack stand and raise it up to the sub frame and make sure its centered (pic 6) now do the other side (pic 7) make sure the stands are locked in place and the lower the car on to the stands and remove the floor jack(pic 8) shake the car to make sure it has settled on the stands before you get under it.
Remove the wheels (pic 9) and don’t let the wheel get away from you (pic10)

[Jay Tee]

Now lock the parking brake (you need it to hold the drive shaft from spinning)
Now its time to unbolt the drive shaft from the differential (pick 11) there are 6 LONG bolts that have lots of LOC-TIGHT on them , don’t lose the retainers (pick 13) once you have all 6 bolts out just wiggle the drive shaft and push it towards the tranny (pick 14)
See all the loc-tight ford put on! It made it hard to wrench the bolts off.
Now you an see the pinion nut (pick 15) now grab the 1and 1/16 socket with ratchet (pic16)

[Jay Tee]

Now remove the pinion nut (if you can) it was very hard to do!! It was so tight that I could not brake it lose with a ½” drive ratchet no matter how hard I pulled or pushed (pic 17) had to borrow an impact tool to remove it (pic18) once I broke it lose with the impact I could now use the ratchet to get it off (pic 19) yep it too was full of loc-tight (pick 20)
Now its off after about 30 min’s of fighting with it (pic 21) damm that was hard!!!

[Jay Tee]

Now its time for the pulley puller to come into play. Use the fine thread bolts to mount the puller putting the bolts 180deg. Apart from eachother (pic 22) now ratchet it off (it comes off pretty ez (pic23) when it starts to come off oil will start coming out (pick 24) Use a 2 quart pan to catch it (pick 25) Now when it feels lose just grab it and pull it away (pic26)

[Jay Tee]

Now remove the yoke (pic27 and 28) and set it aside now you are ready to remove the diff-cover, Notice the sticker on the cover (pic29)now get the ratchet with the proper socket on and brake the cover bolts lose (pic30) all 10 of them (pic31)

[Jay Tee]

Once all the bolts are off use a screw driver to pry the cover off (pic32)and be sure to the pan under to catch the oil as it pours out (pic33) now that the oil has drained remove the cover(pic34)and (pic35)now you can see the stock 3:55 gears (pic36)

[Jay Tee]

Now spin the ring gear around till you see the carrier shaft bolt (pic37) and (pic38)
After I did that I went to the axel hub (the part where the wheel mounts to)
And start to remove the disc brakes (pic39)To remove them you just unbolt them .there is 2 bolts on the back side of the caliper where the rubber boots are at (pic40) now remove the bolts and set aside (pic41)

[Jay Tee]

Now just grab the caliper and wiggle it as you pull away from the rotor (pic42) the brake pads may fall off , that’s ok.,Use a coat hanger to hang the caliper (pic43)so you don’t damage the brake line,
Now remove the caliper bracket its bolted on with 2 bolts(pic44) and (pic45)
Now just pull the bracket off and set it aside (pic46) with the brake out of the way
Now remove the rotor retaining washer (pic47) see it at the 6 o’clock position

[Jay Tee]

Use a screw driver to pry the washer away from the rotor (pic49) then grab it with vise-grips or whatever (pic50) and (pic51)Don’t worry you won’t need em
Now just slide the rotor off the axel hub (pic52) there it is the axel now repeat the same process for the other side..

[Jay Tee]

Now back to the diff.now that you have removed the calipers and rotors its time to remove the axels unscrew the locking pin (pic54) and (pic55) and set the locking pin in a SAFE PLACE, now slide out the carrier pin (pic56) and (pic57) now go to the axel hub and push the axel IN(pic57a)

[Jay Tee]

Now with carrier pin removed and the axels pushed in its time to remove the “C” clips(pic58) use a screw driver to slide em off the axel shaft(pic59) do the same for the other side (pic60)you may have to push the”C” clip out with a screw driver (pic61)
Now go pull the axels out about 4 inches out from the car (pic62) and be careful not to damage the ABS sensor (pic62)

[Jay Tee]

Now that the axels are out (pic63) you will need to unbolt the differential support rod (pic64) and just pull it out of your way as needed (pic65) now brake lose the carrier bearing cap bolts all 4 of them (pic66) and (pic67)

[Jay Tee]

DO NOT MIX THE CAPS!! MARK EM AS YOU TAKE EM OFF so you know what side they came off (pic68 and 69) THIS IS VERY IMPORNENT!!!
Now the carrier is ready to come out (pic71)
Grab it and wiggle it out and catch the shims as they come out with it (pic72) DO NOT MIX THE BEARING RETANERS MAKE SURE THAT YOU MARK THEM AS TO WHAT SIDE OF THE CARRIER THAY CAME OFF FROM!!!!!(pic73)

[Jay Tee]

Now the ring gear will come out (pic74) the support bar will move out of your way when you touch it with the carrier (pic75) now its out (pic76) now I set in the bearing retainer so I can remove the ring gear bolts (pic77) I toke out the traction-loc clutches to inspect them (pic78) YOU WILL NOT NEED TO DO THAT I JUST WANTED TO SEE HOW IT WORKED!!

[Jay Tee]

Everything was good no wear on the carbon fiber clutches cleaned it up a little (pic79)
Clean the carrier housing (pic80) and tap out the pinion gear with a small hammer (pic81) it came out pretty ez.
Now remove the old seal and front pinion bearing and the oil slinger (pic82) I used a cut down broom stick cut to 18 inches long and taped it out from behind (pic83)

[Jay Tee]

Once the front seal was out the bearing just falls right out (pic84 and 85 and 86)
Now clean the front race with a towel to clean up any wood that I might have left from knocking out the seal(pic87 and 88)

[Jay Tee]

Now that’s done get back to carrier and remove the old ring gear (pic89 and 90)
Once you have all the bolts off the ring will just fall off with a light tap to the side with the wrench (pic91) now I reinstalled the traction-loc clutches and spider gears (pics94 and 95)

[Jay Tee]

The old ring and pinion on the left and the 4:10s on the right(pic96) I used the supplied thread lock on all of the ring gear bolts (pic99) then wrench the bolts down (pic100)
Then put the carrier in the vise between 2 pieces of wood and torque the ring gear bolts to 85 foot pounds (pic101) now set carrier with the new ring aside (pic102)

[Jay Tee]

Now get the old pinion gear and heat the bearing with a propane torch for about 3 to 4 minutes (pic103) DO NOT GET THE BEARING RED HOT !!!
Now grab the pinion with a towel or heavy glove and hit the threaded end on something hard like the vise or the floor and the bearing will come off (pics 104-105-106 and 107)or you can take it to shop to press it off!

[Jay Tee]

While the bearing is cooling off clean the inside of the differential case with clean towels
(pic108 and 109)and now brake out the dial calipers cause you will need it to measure the width of the stock pinion gear and the new pinion gear(pic110and 111)the reason you do this is because the is a shim between the bearing and the back of the pinion gear. The stock pinion was 1.878 and the new pinion was 1.866 a difference of .012 smaller and the shim on the stock pinion .020 thick so I put a .030 thick shim on (pic112) so that the pinion setting depth would be within .005 this is another very important step to do because it sets the centering of the pinion gear to the ring gear to maintain maximum gear to gear contact on the heel and the toe of the gears. This dimension will be checked agine when the pinion is installed into the differential… NOTE EVERY CAR IS GOING TO BE DIFFERENT

[Jay Tee]

Now put the new shim on the new pinion then heat up the bearing a little to expand it so that it will go onto the pinion shaft (pic114)make sure that you put the bearing on the right way (the big end of the bearing goes up against the pinion gear) with the shim in place and the bearing still hot steel rod to TAP the bearing down into place (pic115) the bearing should be tight up against the gear (pic116) now look at the face of the pinion gear (pic117) see the numbers? 2.5489” that is the setting depth of the pinion. Write it down!
Now put the pinion back into the differential (pic118) be careful not to hit the bearing race as you put the pinion back in..

[Jay Tee]

Now push the pinion into the bearing race (pic120) and hold it in with your hand and then
Place the new CRUSH spacer on the pinion (pic121) then the bearing (pic122) and (dip the bearing in oil before putting it in) now the slinger (PIC123) and then the new seal (pic124)

[Jay Tee]

Now tap the seal into the differential case (pic125) do not beat it in just tap it in..now put the yoke on (pic126) Now put the new pinion nut on (pic127) now wrench the nut down as you can go with the ratchet (pic128) IT’S GONNA BE F#%&KING HARD to tighten it down! That’s what the wrench on the 2 bolts were there fore. To hold the yoke from spinning around. Get it as tight as you can with the ratchet then get the torque wrench and TORQUE the nut to 140 foot pounds (pic129)

[Jay Tee]

Now look at (pic129a) that flat is where the bearing cap bolts to, that is the center line which is the center of the ring gear and the axles this where the pinion setting depth measured from(remember that number 2.5489” that was etched on the pinion face)
Now I made a plate from a pice of scrap metal that measured .260” thick. I drilled holes in varies places and two 1/2inch holes at one end and then bolt it to the case (pic 130) Now get the dial caliper and position it with the depth measuring side on the plate (pic130a) now slide the caliper open with the depth rod going though the hole on the plate (pic131) keep sliding it till the depth rod touches the pinion face while at the same time making sure the caliper body is firmly against the plate. Now look at the dial face take the measurement (pic132) I got 2.813” now I did that five times to get an average cause I would get 2.810” then 2.814” then 2.812” then 2.813” then 2.815” =14.064/5= 2.8128” so I rounded it off to 2.813. now subtract the plate thickness of .260” from the 2.813” which is 2.553” my target depth is 2.549 with the .030” shim I ended up with a pinion depth of 2.553” well with in the .010” tolerance which is 2.4589 plus or minus .010 which means as long as I was in between 2.539 and 2.559 I am good to go.

[Jay Tee]

Now remove the plate and clean the pinion gear and inside of the case (pic133) and (pic134) now put oil the bearing and on the races then set them on the carrier bearings (pic135 and 139). You did mark em to what side they came off RIGHT?
Now the carrier is ready to be installed in the differential case(pic137)

[Jay Tee]

Make sure that the bearing seats in the diff. case are clean (pic140) and the pinion gear is clean also (pic141) now hold the carrier with the bearing races in place and slide it into place (pic142) you may have to “jiggle” it a little to get the ring gear to go on the pinion gear.now put the shims back in.(pic143) and put the bearing caps on and sung em down then the dial indicator with magnet base (pic143a)

[Jay Tee]

Now stick the indicator to the face of the differential case (where the cover goes) and set the tip of the indicator needle on one of the ring gear bolts on a flat and then ZERO the indicator (pic143b) now gently rock the ring gear back and forth and take the reading from the indicator (pic143c) it shows .003” of back lash. It should be .008” to .012”
That’s TOO tight the gears will whine like a bitch and burn up! So I need to move to carrier away from the pinion .006”
So now remove the bearing caps and pull the shims on the ring gear side and measure the shim thickness (pic146)the shim is .280” thick I need it to be .274” thick so now I picked out some shims from the supplied shims (pic145) and stacked them up till I got .274” (pic147) Now remember what ever you take off from one side you have to put on the other side to keep the preload on the bearings

[Jay Tee]

Now put the shims back in (you will have to tap them back in to place) they should fit in VERY SUNG (pic145a) put the bearing caps back on and snug them down then position the indicator and zero it out (pic148a) now gently rock the ring gear back and forth with out making the pinion move and read the indicator (pic148b) now after changing some shims I am now in tolerance at .010” the specs call for .008” to .012” so I am right on the middle.
Now remove the indicator and get the marking compound and the brush and PAINT about 4 teeth on the ring gear (pic149)

[Jay Tee]

Now turn the pinion shaft by hand and rotate the ring gear a couple of times going forward and then backward (pic150) then look at the paint marks (pic151) it shows the contact point to be right where the specs call for in the center.
Now turn the gear a little more so you can see the “heel” mark(pic154) now turn the ring a little more so the you can see the paint mark on the “DRIVE” side (pic153) all is good to go now its time to torque the bearing cap bolts to 85 foot pounds (pic 169)

[Jay Tee]

Now the new gears are in their new home its time to finish up by putting the axles back in but clean off the bearing surface first (pic171) slide the axle back in till its all the way in (pic172) now clean the “C” clips off (pic173) now that you have the “C” clips cleaned and the axles pushed all the way in you can now insert the “C” clip on to the axle (pic174) where my finger is pointing too. Just slide the clip on to the axle (pic175)

[Jay Tee]

Make sure that you push it all the way on till it bottoms out on the axle (pic176) now use a screw driver to push the axle back out so the “C” clip will go in to its pocket (pic177)
Do the same for the other axle,
Now make sure that the spider gears lined up with the shaft bores on the carrier (pic178) and (pic179) now insert the spider gear shaft and line up the pin hole (pic180) then put the put the locking pin back in and snug it down(pic181)

[Jay Tee]

Sung the locking pin down with a wrench (pic183) then torque down to 25 ft pounds
Pics # 184 and #185 are lust pics so you can see how it looks when done and 185 is so you can see the paint on the gears

[Jay Tee]

Now that you are done with the gears rebolt the support rod back to the frame (pic186)
Put the drive shaft back in place and bolt it back together and torque em(pic187)
Now clean the diff. cover and the bolts and put the gasket on the cover(pic188)
Put the diff cover back on and tighten the bolts starting from the bottom (pic189) working your way up one at atime so you don’t warp the cover
Now remove the filler plug using the square end of a 3/8” drive ratchet with a 6 inch extension (pic190)

[Jay Tee]

Remove the plug and clean the magnet (pic191)now fill the diff back up with synth.lube
It will take one and half quarts I used the Ford lube
That’s it you are now done with the gear install …
Put the rotors/brakes/etc/wheels back on the remove the jack stands pick all the tools up and clean up .
When you are done with all that grab your X-cal 2 and plug up to the car (pic194) and tell the car your new axle ratio (pic195) so the Speedo will be right

[Jay Tee]

Now back on out and go for a test drive (pic196) I went about 10 miles at speeds from
20 mph to 60 mph (NO BURN OUTS YET) it was a successful install (pic197)
it took me about 9 hours over a period of 5 days to complete and yes it was not hard but tidies cause everything had loc-tight on it and if don’t have tools and a place to do it you will be better off having a shop do the install( here in San Antonio the average price for the install was from $800 to $300 plus parts ) like I said in my other post I am not a mechanic and I do not work on cars , I make my living as a machinist and have been doing it for over 25 years and I have a very very good understanding of how things work especially machines of any type and are cars are Machines

[Aviator Stang]

Nice job man, and descriptions!

[Jay Tee]

the 4:10 gears was the best bang for the buck now i have the (put your ass in the seat) accelration.
the only draw back is that now it is very ez to do tire rosting burnouts from 1st though 3rd
my rpms are a littel higher cause of the gears about 350 more rev's

pic#999 is at 70mph and pic#1000 is at 80mph with the stock gears,

pic#1001 is at 70mph and pic#1002 is at 80mph with the new 4:10 gears,

and pic#1003 is the box the gears came in (read the highlite)

[chewie]

Big thumbs up for a nice and very descriptive How-To. Good job on the install.

[Scottyboy]

Good job man!