How to - Welded Center Diff w/ Pics

[GolfBall]

Many opinions on weather its good or bad, this is neither, simply to show you how easy it is to do if you decide its what you want.

first off remove the end cover (11 bolts, 9 short and 2 long)

this is what you will see

remove this pin on the shift fork and pull it off (keep it all together will help on reassembly)

pull the snap ring off the VIS

after you pull the VIS off there is a small ball bearing in the shaft (remove it and keep it safe for reassembly)

remove the two nuts of the gears

pull the three bolts out on the side (be sure to keep the spring and ball bearing all together)

you should not be able to pull the second layer cover off

there ya go... thats it

remove your center diff

throw all this out... its not needed

then weld it up... here is a diagram that shows it as well.

Remove everything with and X.... weld gear 6 to case 4, then weld gear 10 to case 12.

then simply reverse all the steps to reassemble and your good to go.

all wheel drive = 4 wheel drive now.

good luck.

 

[toybreaker]

Very nice write up!

My advice to anyone considering this on a daily driver is to a drive and parallel park a car with this mod before performing it.

ain't no going back /ubbthreads/images/graemlins/wink.gif

[edit] A good discussion (with video's) of the effects of driving a car with a welded diff can be found here

 

[mitsuturbo]

^^^ The montero sport, in 4wd mode exhibits the same behavior. Many selectable 4wd vehicles do. This is why it's "selectable". It's to be used when you "need" it. It may not be a good idea for a daily driver, as it puts a lot of strain on drivetrain parts. You can definitely feel the difference when turning. It is an excellent thing to do for a straight line race car, though.

 

[grocery_getter]

Be sure to use a junk vcu to jig the top hat and the top output shaft. Be sure to also use another used bellhousing to jig the lower gear and the lower housing.

The lower gear has the internal spline thru which the transfercase output shaft fit thru. The problem is the clearance between the lower gear and the lower housing. It is meant to be centered to each other using the transfercase output shaft. If it is just welded as is on table top without being jigged the right way on the lower bellhousing using a big long bolt and nut to keep it centered and tightly down during welding (metal moved during welding) then when it is done and reassemble the lower housing will not fit right in the lower housing bearing outer race.

Same problem with welding the top hat to the top output shaft together. It needs to be jigged using a junk vcu otherwise the side to side clearance between the OD of the top output shaft and the ID of the top hat opening will cause the output shaft to be welded to one side. This will make fitting the VCU (or what ever else is being used to retain the ball such as a vcu eliminator unit) that depends on the 2 set of vcu internal splines lining up just perfect with the 2 set of external splines of the top hat + top output shaft practically impossible.

Andre

 

[GolfBall]

i welded mine up sitting on a table and it re-assembled with no issues and worked just fine?

 

[toybreaker]

While I understand your point, when it comes to jobs like this, the penalty for getting it wrong is high enough that it's prudent to take some extra steps to make sure the job turns out well.

I have seen this job turn out poorly, and the penalty can be damage to the internals or transmission case, and that's an expen$ive step in the wrong direction.

Making a jig is going to increase the chances of success considerably, and it's sheer genious to use the case/other parts for the task.

Andre, shoot us some pics the next time you're doing this task, please.



Also, for you guys that are doing this type of stuff, please take some time to ensure your own safety!

OSHA has some generic info on the subject, but there are some special considerations when it comes to cleaning the parts prior to welding.

Many of the solvents we use in the shop are very hazardous when super heated/exposed to intense ultra-violet radiation.

This is especially true of chlorinated brake cleaners


A little time and care taken now will cut down on "interesting" health problems later in life. /ubbthreads/images/graemlins/wink.gif

 

[GolfBall]

i usually throw caution to the wind and just go to town with the welder but that is a very good point.

when stuff starts burning off when you weld and you catch a sniff of it and it kick's you in the chest you realize its not a bad idea. /ubbthreads/images/graemlins/smile.gif

 

[GolfBall]

ANOTHER REASON TO DO THIS:

this just happened to me at the track over the weekend.

broke my rear drivers axle.... thanks to my welded center diff i just pulled my transfer case and driveshaft was able to keep racing front wheel drive. /ubbthreads/images/graemlins/smile.gif