Keith

So I picked up a AP1 differential for cheap price knowing that it was probably blown (seller is a Honda mechanic and removed it from some kid's S2000 after he blew it). All he knew was that it would 'lock up' apparently. I figured the price was so low that it would be worth the investment and tackling on learning how to rebuild a differential (I do my own mechanical work... t-belts, replaced motors, valve adjustments, etc) and possibly throwing this one on my S2000. Worse case scenario is I would have a bunch of parts as paper weights and stuff to display in my office.

First thing is first... I try to drain it and found this stuck on the magnetic drain plug...



Yikes... Not a good sign...

I pop off the output shafts...





I remove the differential case and clean up some of the oil...



I start finding more metal chunks... not shavings or pieces... CHUNKS



I can already see the pinon is heavily damaged...



I proceed to mark the bearing caps and adjustment screws on both sides



Not sure if this is a normal but one cap looks like it might have shifted...



One of the lock plates looks like it has shifted too...



Bearing caps off...



More chunks from the pinon...





LSD + ring gear...



Using an impact gun, I removed the locknut



The companion flange popped off using a puller



Drive pinon out...



More chunks...



Pinon totally trashed...





Ring gear damaged



I had to stop to BBQ for dinner but this will be a part time project... Do you guys think that other than the pinon and gear, the rest of the parts might be salvageable (besides the various seals, spacer, clips, washers that need to be replaced anyhow)... or do you think it's pretty much junk? If it's salvageable, I might plan on getting a Kia 4.77 gear + pinon...

Keith

S2KPUDDYDAD

First, great pics

It can be rebuilt from the looks of things. The bearing caps and clips will sometimes be off a bit, this is normal.

You will need to replace all seals and you will want to replace the pinion bearings, pinion nut, and crush sleeve.

Marking the spanner nuts is not necessary because, with a new gear set backlash will change.

Place the stub axles back into the LSD loose to see if you can turn it, if not it maybe broke too.

I can give you some help via a phone call if you like. I can also repair it for you, I have all necessary tools and parts and a little experience

Keith

I was hoping you would chime in PUDDY, since you are an expert on differentials. Before I bought the diff, I searched the forum to find more information on rebuilding it and your name would come up all the time. Trust me, if I get too over my head, I'll be contacting you for help or shooting it over to you to finish off. But I'm interested in learning how to do this myself so I can add this job to my resume...

As far as replacing the bearings and crush sleeve ... are you referring to parts 28, 26 and 29?



I put in the axle shafts into the LSD and was able to turn it but it would lock occasionally... My guess is that there is a chunk still in there some where that is jamming it. I'll investigate it when I remove the gear.

What are your thoughts about the Kia 4.77 pinon and gear? My S2000 isn't FI and I won't be doing any hard core engine mods to significantly increase the horsepower a lot. I might do an occasional track day with it though...

Keith

negcamber

Good luck Keith...Ben, aka Puddy, is the master.

I wonder if the torsen is hosed. When my diff blew, you could also see damage to the little worm gears in the LSD.

S2KPUDDYDAD

Replace 9, 10, 24, 25, 26, 28, 29, 31, 32 x 2, you may or may not have to replace 11, inspect 19 x 4 and 30 x 2 for damage. Be sure not to mix number 30s bearing cups, be sure you keep the cup and the bearing it goes with together.

Do not take the LSD apart, wash the LSD out very well with 100% mineral spirits. After it is clean use a little 10 w 30 oil and wet the gears down through the windows of the LSD. Insert the stub axles loose and twist back and forth and try to free up the unit. If you can get it to spin, great!!! If you can not get it to spin it maybe that one or all the planetary gears are damaged.
If it is damaged then you are looking at a very expensive project, the LSD is the most expensive part of the differential. No parts are sold to rebuild the factory LSD, the LSD is sold as a unit. To replace it will cost $$$$
We have the machines and our own parts to recondition the factory LSD unit if it is damaged.

Good luck

Keith

Thanks again Ben... I'll pick up some mineral spirits this weekend and wash out the LSD unit... I started to put together a list of parts I needed to get and I think I have anything you listed as well. It looks like it's going to cost another $150-$200 in parts + a new pinon and gear at the very least...

Does anybody have any recommendations for a dial indicator? Is a specific brand better than another?

Keith

Keith

Update with pictures...

Pinion oil seal, outer race bearing and tapered roller bearing...




It's funny how the Helm's shows the outer race bearing can simply be pushed out with a screw driver... I had to use a screw driver AND a hammer to 'push' it out along with the oil seal.

Roller bearing looks good..






Same with the oil seals for the axles... the Helms manual shows you can 'simply' pry it out with a screw driver... which translated to using a screwer AND hammer to knock it out.

Before:


After:


Breather plate removed from the differential case:


Remember the LSD covered in sludge? After washing it thoroughly with mineral spirits...




Differential case after being washed (to make sure there is no metal shards left):


A gouge inside the case thanks to the pinion being shredded to pieces:


Keith

starchland

wow nice project. Im guessing you bought this known it was already made into pumpkin pie?

MasterForce

nice!! hopefully you can salvage it and if yours ever breaks you can just remove and replace it...

SoCalIsMyLife

Wow that's some serious damage! At least the chunks didn't get stuck and shoot the whole ring gear out of the bearing caps. Good luck on the build man. The bearing caps are sometimes slightly off.