I first heard of welding difs (differentials) many years ago. I was a skeptic at first. I knew of one particular instance where one had failed under hard use. I advised people against them after that and referred to that example pretty often. Then a couple of years ago I heard some very contradictory stories about welding 6 lug Toyota rear ends. I heard that when done correctly they will never break. You will break an axle or a driveline before the welds on the side gears and spider gears and carrier all give way. The people reporting this have extensive experience testing Toyota trucks under hard use so I took their word for it. I took the third member out of my rear end and welded the side gears to the spider gears first, theoretically to warm the cast material in the carrier prior to welding it to the gears. To weld the gears to eachother, just start welding in between the teeth. Alternating sides with each pas to distribute the heat evenly. I did three passes with .045 flux core dual shield MIG wire. If you don’t have dual shield wire it’s probably ok, but I would try to run at least .035 MIG wire and a 250 amp welder or something in that realm. I wouldn’t trust my little Millermatic 175 for a job of this importance, although it’s a great machine (the smallest Miller offering that runs on 220v). So anyway, after three passes between all the teeth that you can weld, the whole thing is getting pretty good and hot. Then it’s time to weld the gears to the carrier. These welds are pretty straight forward. You can get at them really flat and I found it pretty easy to get a good weld from the cast carrier to the gears. An essential step in the process is getting all the slag and weld dingles and crap out of there. This takes some effort, but you really don’t want to leave any of that stuff to get mashed in between the ring and pinion. There is going to be some amount of this stuff left that you just can’t get to without removing the carrier and ring gear from the housing, but this is not necessary to do the job. You will want to change your dif oil within a week or so after welding the dif to get out any excess grit left in the oil. Mine actually sparkled in the sunlight. The amazing thing is that this actually works to lock up the rear end on a six lug yota rear end, and it wont break. I have been running mine now for about nine months or more and I drive it on pavement almost daily. It definitely has some quirky aspects to it. It chirps or scrubs tires around corners and this will get you dirty looks sometimes, but it’s worth it when you peel out and leave two streaks instead of one weenie streak. No more one wheel peel. That’s for sure.

So that is my experience with welding Toyota difs, and it has me curious about the potential for welding 5 lug yota axles. The 6 lug stuff that came under 4x4 Toyotas was really over built. Are the 2wd versions strong for their weight class? I want to try the same basic principles and weld a 2wd dif (once I have some spare parts). Does anyone else have any experience with this?

 

i think mine should hold.... after all, it's been through all my abuses

 

I'm confused, is your dif welded?

 

Hmm, I haven't personally used a welded diff but I know that a particular guy on here who welds quite a few for his customers. He goes by the name Beefed Taco. Though maybe one day I will join the ranks of having a welded diff but then again I'm lazy

 

Yeah, it's not exactly easy, but then it's not really the hardest thing to do either. It is easier than putting in a limited slip differential because you don't have to deal with setting up the shims on the ring and pinion which is pretty technical and a major pain in the @ss. To get the third member out you just have to unbolt the driveline and the axle shafts (four bolts each side) and then the whole third member comes out of the rear end as a unit. You can put it on the table for welding. Once I get around to welding another one I will take a bunch of pics. It is actually pretty straight forward though.

 

nah, I don't have one. I currently have the F series 7.5" rear end... its just that after 158k miles, would my diff be strong enough to be welded? I'm sure it is, i'm just doubting it thats all.


I also need to check my differential fluid.. eek!

 

Whenever you weld something the weld isnt supposted to break. If its a good weld something around it will always break before the weld. Anywho you guys run a welded rear end daily? Hows the abuse on your tires?

 

ummmm.... outshield welding wire.... by far my favorite wire is the dual shield. i used to use it to reskin belly dump trailers.

 

Yeah, I run a welded rear end daily, and that was with 33 inch tires in a super soft compound up until a couple weeks ago when I put on 34 inch tires. so I think in contrast a 22-24" od tire shouldn't be too much at all for a welded dif to handle, especially the 4 speed rear end, but I don't really know for sure. Just a hunch. About tread wear, it is barely noticeable over the fronts on my truck, surprisingly. I guess it is just balancing out with the increased wear from engine weight. I also haven't been getting sideways on the pavement at all with the new tires and that is what I am going by. It depends on how you drive for sure. When my 33s were getting bald I had a lot of fun getting sideways on the curvy highway roads around here and that eats them up pretty fast. Lately though I have been taking it a bit easier. I would say the tire wear is not that bad of a concern really if you can deal with the manners of the tires scrub on corners and some other erratic behavior. The traction can't be beat in most situations, but when it breaks loose it is both tires breaking loose and this behavior takes a little getting used to.

About dual shield wire, I find .035 makes the prettiest welds of anything I have run (MIG-wise). The .045 is just way hotter and has some serious penetration. I have done pretty heavy stuff with .035 dual shield also (actually got my certification for all positions welding up to 3/4" with it) and it works fine, just takes a few more passes then the .045. The .035 ESAB dual shield wire we run works beautifully. I love when you get a tough weld like an uphill or something and it just peels it's own slag perfectly and comes out looking pristine. You can't beat it.

 

we ran .045 using a old miller with the mig attachment. the thing ran on 480! i could weld out about 50' of seam in less than an hour with it. the place i work now doesn't have it...... makes me sad..

 

Damn! That's serious! That's a lot of weld (and a lot of heat)! Hope the shop wasn't too hot and had some good ventilation.

 

yeah it was about 80x120 and had 5 industrial size coolers! cost them $50k. but it was 80* inside during the summer (in the area of the vents of course).

 

That's good they were properly equipped anyway. Even at 80 degrees it would get pretty hot, holding a 12,000 degree arc at arms length. I don't do to well with extreme temps. I probably couldn't do this job if I lived in AZ. Where I live the climate is pretty moderate. At least out there it's so hot that shops probably have to invest in proper cooling/ventilation equipment.

 

actually most don't..... the shop i'm in now is 120* during the summer. and thats when nobody is welding. its miserable.

 

several of my buddies have lifted 80's-90's yota's with 37's and welded rears and have never broken a diff or welds.

 

i run a wleded diff done by Beef Taco. i came up with a similar desighn used in some race/drift applications where its don "on the cheap" and i have to say its held up damn well!

here was some of the "test" video's






btw....... i have driven it in the rain, over freeway ramps, overpasses and everywhere else and contrary to what everyone sais, its not dangerous.

you just gotta have a clue and know how to drive to keep your truck in control, but no "unexpected" fishtailing or whatever else everyone else sais about how dangerous one is.

this was a GREAT mod for the buck. im real happy with it. i also know of another guy running about a 300hp turbo tacoma and he's yet to budge anything in there

 

what kind of exsoust u runing on ur truck, sounds good

 

Nice! That's awesome. See that's why I want to weld up my 2wd. My 4x is so tall, I get sideways in it on the pavement, but I can't do maneuvers like that. It's too tippy. I have had it on 2 wheels cornering uphill on pavement and I really want to keep the shiny side up on it... But in a lowered truck it would be on. Those are sweet videos. And that exhaust does sound nice.

 

im running a downey 4-1 header, catless 2 1/2 exhaust with a magnaflow muffler run as close to the cab as possible, pipe run out the stock exit location..

 

I just welded up the rear end in my '89 and thought I'd share a pic. I used a 220 MIG, it was just a little Millermatic 175. This is the bare minimum I would recommend using to weld up a diff. I welded the gears to the gears (between the teeth), then the gears to the carrier, alternating sides to distribute the heat evenly through the carrier. I did three passes on everything. This is my first 2wd axle I've welded like this, but I've done extensive testing on my six lug welded rearend in my '79 4wd and it has held up great. It's not an exact science, but if you weld up a Toyota diff like this you should break an axle before you break the carrier or welds.