Taking out The Diff:
Begin by jacking your car up from the pumpkin and then putting something at least 8” high underneath your rear tires. Put stop blocks (bricks or something of the sort) in front of your front tires to make sure your car doesn’t start rolling away. Lower the jack and put it to the side for now.

Take your car out of gear and release the parking brake.

At the jack point on the passenger side of your subframe jack the car up until your subframe stops lifting. YOU DO NOT WANT TO RAISE THE CAR, JUST PUT MAXIMUM PRESSURE ON YOUR SUBFRAME BEFORE LIFTING IT.

Now begin to disconnect the pumpkin from the subframe on the right side. There is one bolt near the driveshaft on the right side, use a 17mm socket to disconnect it.

There is one nut and one cap on the back of the differential, use a 14mm socket to disconnect them. Lower the jack and repeat the process for the other side of the car.

The diff on the left is the one I was working with, while the one on the right is a VLSD from pdm-racing's website. Using the second pic to highlight what you need to remove.

Next, remove the bolts to your axles. You don’t need to jack up the car from any points to do this. There are 6 bolts that require a 14mm socket to remove them on each axles. DO NOT PULL THE AXLES OUT!

The last set of bolts are to the driveshaft input shaft. There are 4 bolts that can be plainly seen and also require a 14mm socket to remove them.

Now for the final step to pull it out. I never have, nor recommend using a jack to lower the diff out of the car unless you have the car pretty high in the air. Carefully remove the axles out of the output shafts and let the differential drop to the ground. More than likely the input shaft will snag on the sway bar when falling. It doesn’t hurt anything, snag is a bad-sounding word for it. Just lift it up off the sway bar and pull it out.

Congratulations, you are one-third of the way there.

 

Prepping the Diff to Weld:
Begin by removing the 8 bolts from the diff cover using a 14mm socket. This is where a pipe will come in handy. There’s a lot of torque on the cover so having a driver or some sort of pipe to get more torque really helps.

Leave 4 bolts on opposing end loosely in still for safety precautions. If you haven’t already drained the oil, now is the time. Screw the drain plug, you’re about to take off the diff cover. Put the diff in a bucket or somewhere, where oil can spill. Now take off all of the final bolts. One final step before you remove the diff cover…..don’t be an idiot, remember what is up and what is down on the diff cover and the diff. Even mark the top of the two if need be. There are two small tabs that have a very tiny hole on each side of the diff. I recommend wedging the chisel in one of those two points and then bashing the hell out of the chisel with the hammer and break it apart.

Sorry the pictures don't really feature it. Remember the picture on the right is of a VLSD. If you look real closely on the picture on th left you can see how the tab actually has a little hole to it while the VLSD doesn't (but at least you can visibly see where the tab is).

Great, now your diff cover and differential are apart. You have spilled oil everywhere, you can see the gears, and your gasket is absolute trash. No, I don’t care what you say and how you believe you managed to salvage the gasket, you didn’t, it’s garbage. Peel it off and throw it away, we’ll take care of that problem later.

Your next step is to clean everything up, this is where you need the brake cleaner. First, take a rag and try to scrape out all the grime, gunk, and oil inside the differential still. Don’t use that stupid little long narrow nozzle that you can hook up to the spray part of the can. Spray all of the gears with the brake cleaner. Spin in the input shaft and rotate the inside gear 180 degrees and spray the other side. You want to absolutely douse the gears in brake cleaner. You should have less than a quarter of the bottle left after spraying all of the gears, you just want to make sure you get everything good.

(Brake cleaner is great because it’s non-flammable, leaves little residue, dries fast, and cleans anything perfectly without scrubbing)

You’re going to have a bunch of the cleaner now sitting in the bottom of your pumpkin so be sure to tip your pumpkin over to get it all out. Let it sit for about 30 minutes and dry.

Welding the Diff:
If you have a deep painter’s bucket (one of those buckets you get from Home Depot), rest the output shafts on each side of the bucket and have the pumpkin sitting inside the bucket. This makes it easy to see and weld the diff, plus it gives you room to get your hand inside to rotate the diff at the input shaft.

Have the four inside spider gears facing straight up at you. If you have a fan, put it on the differential. You want to suck up as much final vapor from the brake cleaner as possible. Although it works great cleaning, it releases horrible horrible fumes when welding so you want as much vapor gone as possible or you will only be able to do a little at a time.

Now do your basic welding preparation.

As you can see in the pictures below, you want to weld the corners of the four inside gears, plus the case. The goal is not to be pretty, but to get good penetration and make giant blobs. On the outer gear that’s easiest to weld the two corners of, weld to the case. I know you cannot see it in my pictures, but want to weld all four gears together. DO NOT FORGET TO DO THE OTHER SIDE!!!!! Once you have welded the one side, spin the input shaft so the other side of the gears are facing you. Repeat the welding pattern on this side as well. (You can't see the inner two welds).

Link to hi-res pic with welds circled
Link to hi-res pic without welds circled

Other side:

Link to hi-res pic with welds circled
Link to hi-res pic without welds circled

It is completely normal to have some binding after doing this, remember, it's not use to work as a solid rear axle and your gears are also dry as a bone.

 

Putting it all back together:
Pour in a quart and a half of gear fluid into the diff (making sure you pour directly onto the gears).

So everything has cooled down, your ready to put your cover back on and put it back in the car. Get out the RTV Silicone. You want to put it all around where you had the gasket before hand, circling around where bolts are placed. IT’S OKAY IF IT GETS INSIDE THE PUMPKIN!!! IT WILL NOT HURT ANYTHING! MORE IS BETTER!

You want the blue tube because it dries fast. The other types take forever to dry, and well, suck. RTV Blue FTW!!!!

Put the diff cover back on, put the bolts back in and torque them down. There are no torque settings however I do it til a point where I simply can’t push any harder while using a pipe or torque wrench.

Time to put it back in the car. Put the diff on a jack and slowly raise it up into position. First connect the pumpkin back to the subframe. Connect everything to the subframe somewhat loosely at first. Next, you want to slide the output shafts back into the axles. Don’t bolt them back in yet. Now attach the driveshaft. Don’t torque the bolts on too hard but you want them in somewhat securely. It is also easier to get the differential back in if you unattach your exhaust and either take it off for the time being, or just undo it enough to push it to the side and out of the way. It may seem like more work, but it makes things much easier and gives you more work space under the car.

It’s hard to explain by typing, but it will be a lot easier to align the bolt holes with the axles again by having someone sitting in the car putting the car into and out gear along with working the parking brake to lock things while you spin things around.

Now just securely fasten everything and drop the car back on the ground.

Yay! Now you have a solid rear axle and can be a mad cool drifter!

Final Thoughts:
Do not push the car for about 2-3 days after putting the diff back in. The welds are fresh and you want to allow the car to get used to it before you really bang on it. You can, you more than likely won’t hurt anything, but better safe, then sorry.

Sorry I don't have more pictures, I'm just not a big picture taker and once I get working I forget I brought the camera and don't want to stop. And once again, please comment, give me feedback, tell me any questions you have, if you need troubleshoot, suggestions of things to add, or just ways in which you did it differently that you think made it easier. Please post! This took me way too long to write and put together to just be ignored.

 

so this is deff. the best right up!

sticky for sure

p.s. engine crap is almost done, then its to putting in cluster and reinstalling the interior and while im doing that i'll either ship or drop off the big ass diff lol

 

best write up

 

did you weld it with a mig? do you think it will be reliable? would just filling in between the gears high lighted in yellow, make it more reliable and stronger?

 

did you weld it with a mig?

Mig Welder (at least 55A output, recommend 110 at min)

do you think it will be reliable?

I have welded several differentials and have yet to hear of an occurrence of any of them breaking. The write-up below is the procedure I have performed multiple times as by others I know. My friend currently has a rb26 s14 with a differential I welded for him over one year ago. The car has 630whp, is a daily driver, and is beaten on constantly. The differential still has not broken. I say this to reinforce that if you weld and pre-treat the differential the same way I do, you will not have to fear broken welds.

would just filling in between the gears high lighted in yellow, make it more reliable and stronger?

Have you ever welded before? I'm just asking because it seems like you are uncertain on how welding works. More is not always better, and this is one of those cases. The key is to get good penetration, and if you really go to town on it, fusion. If you have a blob just to fill in a section there is a possibility of that blobs breaking off only and causing catastrophic failure. Yes, it could be good, if done right, but it is also overkill. It's the same reason I'm against using bolts to jam the gears, then welding them. If a chunk breaks loose, you're fucked, and it wasn't necessary to begin with.

 

oooo got em!

 

OMG, i think thats my old ass diff being welded. Letting everyone know i put it in today and it works great. Put it to a little test of some 1st, 2nd, and 3rd gear tire spinnage and it holds great. Good work Jesse. Best write up in this section as well. Keep up the good work.

 

awesome thread if i had a welder i would surely try well my diff. now thumbs up for great how to:thumbsup

 

is there any shaking or vibration coming from the rear end when sliding or spinning the tires. i keep hearing mixed reviews from people about this just wondering if your car shakes or vibrates when your pushing it thru some corners.

Thank You.

 

My rear end shakes (up and down) when launching or burning out but that is simply because my subframe bushings are rotted beyond belief and I was supposed to replace this winter (oops). Sliding the car there are no shakes....besides the whole my car is a piece of crap and falling apart every second the car still stands.

 

I personally wouldn't recomend this on a street car. Im into old cars and drag racing so I know a bit about spools (basically a sophisticated version of welding the gears) and the principals behind an open differential is to allow one wheel the freedom to turn faster than the other while going around a bend. The thing with LSDs is that it still allows this but under accel mostly in a straight line both wheels are directly connected and provide equal amounts of power or speed. When you lock both wheels permanently and you take a bend the one wheel that is supposed to rotate faster can not and in turn will drag. This causes some problems on a daily driver such as rough ride and abnormal tire wear. If you can live with this or have a strictly track car/ occaisonal street driven car then a "lincoln locker" is a good cheap way to acheive equal power to both wheels.

 

I really, really don't mean to sound dickish, but all you said was stuff that pretty much any average joe could figure out if you had a solid rear axle. :heyhey

Yes, it doesn't make it not THAT daily driver friendly, but you hardly even notice it after a while. Yes, you hear the chirping and in my case the wheel hop because of the junk subframe spacers, you have to know your boundaries, but it's not THAT bad! Everyone always says "you're going to have bad tire wear", but if you are welding your diff, aren't you doing it so it's easier to burn up your tires anyway?!?! (whether it's drifting or just trying to get traction launch a drag car. All cars I have welded a diff for were all daily drivers and no one has complained.

cool Write up. i welded mine about 3 months or so ago as you know with my flux welder (16 points). but the pentration was horrible. and it all came apart after 1 month. im picking up another and welding it again this time with an mig

Donnie, let me know if you can't get your hands on a mig, I'll help you out. :thumbsup

Yea good write up! I also dont recomend this on a street car, expecially if you live in CA, or another area where cops are haters. All it takes is one little low speed corner to make the wheels churp, and make a cop want to come afte you. They are a shit load of fun though!

Haters? Kevin (KB240SR) got pulled over with his welded diff in because it was chirping tires through a corner. The cop asked him why he was chirping tires and he straight up told the cop "my differential is welded". The cop told him that it is illegal, and Kevin told him no it isn't. (There are clearly no laws in any of states that you cannot weld your differential locked.) Cop walked to his car for a while, made some calls to find out, and wound up writing him a warning for speeding 30 in a 25 (cop said he was in a pack and couldn't pull over everyone so he chose him).

Bleh! So all that said, there's nothing illegal about it, there's nothing that you can get in trouble with the cops for, and the only way you can get yourself by driving with it on the streets is by driving like an idiot and intentionally sliding it.

It takes more brain power to remember to breathe, than to remember through a corner, "Hey I have a welded diff, remember not to let the rear end slide out.".

 

Good Write up Jesse, but id also have to Agree "fakingdeath" on the Street car comment.

EDIT: Dam this was a good format for a DIY, i like it alot. The details etc..

 

cool Write up. i welded mine about 3 months or so ago as you know with my flux welder (16 points). but the pentration was horrible. and it all came apart after 1 month. im picking up another and welding it again this time with an mig

 

Yea good write up! I also dont recomend this on a street car, expecially if you live in CA, or another area where cops are haters. All it takes is one little low speed corner to make the wheels churp, and make a cop want to come afte you. They are a shit load of fun though!

 

drifts135: i got my open diff welded by one of the shop here in oceanside, cali. me and my boy(secretsquirrel) didnt have to tell him how to weld it. he did a very good job on the welds. i looked at the pictures you have and they are almost similar. we did the clean up and all before we dropped it off. you have a good write up. so the extra open diff we have, secretsquirrel is going to weld it himself. but :thumbsup for you. your write up helped out and steered me to getting a welded diff. i will leave feed back about it. JOB WELL DONE.

 

Yea, that was funny getting pulled over for my diff. Or was it for going 30 in a 25 in a pack of 6-10 cars? Either way the cop couldnt really do anything.

 

Good write up! Only thing i suggest is that you make sure the area you are welding is clean. I would go as far as to grind the area before you weld it. This will help penetration a lot. And belive me, penetration is the single biggest thing you want so that the diff will stay together longer. Belive me, my welds at work get microscoped on a daily basis. And if it doesn't scope than it gets cut out and put back in. Like said before, i wouldn't try this with anything less than a 110.

As reference what type of voltage and wire speed feed are you using?

 

The nice thing about brake cleaner is that it works perfectly for cleaning up any and all gunk and leaving a smooth surface. I know I took some super high res pics, but they still don't give justice to the welds. They aren't the prettiest things in the world but I got A-mazing penetration.

Voltage, wire feed reference. All settings on all welders will differ slightly, but I like around around 3/4 voltage and 1/3 wire speed, depending on the mig. Working with a diff just high voltage low wire feed is a combo, but it doesn't have to be crazy duty cycle.

Great job... I've daily driven my welded with 255 wide tires for 6 months or so... Drives just fine.. Be careful with hard downshifts in corners(DUH!). It gets a little annoying in parking lots with a girl in the car because of all the THUD THUD THUDS coming while turning slow. Driving in the rain can be scary IF YOU ARE RETARDED. I can punch it at almost any speed and get the rear loose..... With all that panzy bs said......its fun as hell to have in the car!

The only prob. i have with your writeup is jacking procedure. You didn't mention jackstands and they should be used EVERYTIME someone crawls under the car.
2. i think brake cleaner IS flamable...but not positive.

Haha, yeah you're right. Of the few times I've actually pulled the diff out, for some reason we just never had jack stands so we just always improvised. Should use jack stands just never have, whoops. I'll add that detail in today.

Check out the bottom line in white letters.

Anyway, last line if you can't read it says "Non-flammable". Yet another reason why I love brake cleaner, it's just perfect for all kinds of jobs. The only way brake cleaner could be more perfect is if it didn't have so many horrific vapors. If you can't vaporize the diff completely before you weld, you won't be able to breathe at all.

 

Nice right up definately a good DIY project for one who wants to weld their Diff.

 

Great job... I've daily driven my welded with 255 wide tires for 6 months or so... Drives just fine.. Be careful with hard downshifts in corners(DUH!). It gets a little annoying in parking lots with a girl in the car because of all the THUD THUD THUDS coming while turning slow. Driving in the rain can be scary IF YOU ARE RETARDED. I can punch it at almost any speed and get the rear loose..... With all that panzy bs said......its fun as hell to have in the car!

The only prob. i have with your writeup is jacking procedure. You didn't mention jackstands and they should be used EVERYTIME someone crawls under the car.
2. i think brake cleaner IS flamable...but not positive.

 

It gets a little annoying in parking lots with a girl in the car because of all the THUD THUD THUDS coming while turning slow.

What is the thud noise anyway?

 

huh...I learned something new then!

I wasn't too good about using stands either...untill a friend who rides in fire trucks talked about cars falling on people, and having to do CPR on them...He said their ribs get so smashed that he could prob. push down and touch their spine during cpr...GROSS!

 

is between 80 and 110 good for welding a diff?

I asked the guy who welded mine with a huge ass blue welder(forgot the name, but its a popular brand).... He said "i think it was 80 or 110...somewhere in there." does that sound right?

 

Blue is gonna be a Miller, imo the best out there. And that sounds fine for welding it.

 

I forgot to mention great write up, and I wasn't implying that you CAN'T street drive it this way just trying to make people aware of what they are getting into by doing this. But again great job on the write up. I was wondering do you seem to have any warping issues with diff causing it to bind in the bearings or against the caps or anything?

 

nice writeup!!!
jus wondering though, the big ring gear isnt a part of the open diff right? so if i weld the other gears to the case, then decide to buy a real diff, would i have to find another casing or is it a complete replacement?