Firefighterformula

Hi all.

Currently I am smack-dab in the middle of a rear end swap. I drive an '02 Formula A4 with the 2.73's, and I am swapping in a rear from a M6 WS.6 with a Torsen and 3.42's. I decided to do the swap when my fuel pump started howling, and since it would be easier to do the fuel pump repair without a rear-end in the way, why not swap?

ANYWAY...

I noticed that the Torsen 3.42 rear, when you spin the hubs in opposite directions to make the diff gears actually turn, they make a kind of "grinding" noise, and are VERY hard to turn. My old 2.73 with a Torsen spins effortlessly and is quiet when the hubs are turned opposite ways.

I got the 3.42 rear from a guy on here who has a great seller's reputation (and knows a LOT more about these things than I do) and he said it was silent prior to removal from his car. The only thing I did to the rear was pull the axleshafts to install my e-brake/caliper mounting brackets. When I pulled the axleshafts, I made sure nothing inside the differential moved. I thought maybe I reinstalled the pinion spacer backwards (if that's possible) so I pulled it, flipped it over, and still the same noise and difficulty to turn.

When I turn the driveshaft yoke, both axles turn forwards, and are silent.

The C-Clips are seated properly, and the little 5/16" head bolt that retains everything in there is tight. What could I have screwed up? Or is this normal for a Torsen?


Any help would be greatly appreciated.

Firefighterformula

Anybody?

It just feels like the diff gears aren't meshing right somehow. They look great (better than my old 2.73 diff) and my supplier is pretty trustworthy. Did I mess anything up when I pulled/reinstalled the axles? Once my Racetronix pump gets here the 3.42 rear has gotta go in; I just want to know if this is something I can fix, because I'm afraid it's gonna grenade once I put it on the road as-is.

Thanks!

jimmyblue

iTrader: (11)

You're sure it's a Torsen, right? Both of mine have
always spun opposite and quiet. Any chance you got
an Auburn chunk or something?

Firefighterformula

Hey! Thanks for the response. Yes, its a Torsen...the guy I bought it from says it is, and it also matches my 2.73, which is a torsen. That being said, I guess im not 100 percent sure, lol. With all this noise and grinding, I bet I messed something up when I pulled the axleshafts...but what??

jimmyblue

iTrader: (11)

Well, my first Torsen had made a whole lot of shavings
and maybe you got some of that swarf up in the gear
cluster, or something? Maybe a nice douching on the
parts cleaner rack, whilst rotating the axle shaft-inputs
might chase out any such crud? Big fun, taking it out
again, but at least a thing to try. I never heard or felt
anything from all that metal debris but didn't like the
look of it so I swapped up to the tougher, higher bias
one.

Firefighterformula

Yeah, that sounds like a plan. While I'm at it I can check for any installation mistakes that I might've made along the way. SOMETHING's amiss, for sure. It's really hard to put into words how its acting, its just not right.

No fuel pump yet, so I've still got some time to mess with it and see if i can figure something out. Time is kind of an issue because my car is in a million pieces on someone elses garage floor. Ordered a "Granatelli" 255 LPH fuel pump from Summit (which had "WALBRO" stamped on it) that was supposed to be a "direct fit" for the stock unit. NOWHERE CLOSE. So I'm waiting for a Racetronix.

Is there any way that the gears could become "unmeshed" (for lack of a better word) with the axles being pulled out and reinstalled? Thats what it feels like...

Thanks again, jimmyblue.

veee8

iTrader: (40)

It is definitely a zexel. It sounds like the diff is not locked together. I remember playing with it on the jackstands, and when you turn the pinion the diff is locked and both tires turn, when you spin the axle shafts, it should unlock and allow it to spins. It sounds like it is hung up and not releasing. Try rocking the axle shafts to see if it will release.

Firefighterformula

Will do!

Thanks bro.

Firefighterformula

Well, a little update...

Took the rear to my mechanic, and he said something is DEFINITELY not right in there.

Should know what's up tomorrow.

DC8808

i'd agree. that thing's f*cked up. the guy lied to you.

Firefighterformula

UUGGHH....

Still no word. Called yesterday and he hadn't even taken it down yet. I have GOT to find a new mechanic...

veee8

iTrader: (40)

Nice.
The whole point of me leaving the cover off with the fluid in it, was to show how great the condition was of that rearend. Clean fluid, that was a year old, and no metal stuck to the magnet. I didn't have anything to hide, and wanted it to be seen how nice it was. I will state again, that I believe that it is somehow the Zexel is not fully engaged. I will warn you that your average mechanic is not even going to know what the Zexel is or how it works. I know for a fact that when you left with it, it was in perfect working condition. It was on jackstands and I spun it by hand both ways.

Firefighterformula

No worries man, I believe that.

I'm sure I screwed it up somehow...I just want it fixed.

Firefighterformula

In case ya'll were wondering...

The install was a BITCH...maybe it was the BMR LCA's, or my unibody has flexed or something, but the rear suspension just didn't wanna go back in.

But after I got the LCA's, Racetronix, and 3.42 10 bolt in from Veee8...

Its AWESOME!

Get better traction than I ever did...(maybe my old 2.73 Torsen was broken?) And I bet for the money I've spent, this is the most SOTP difference I could ask for. Absolutely no problems from the rear after approx 1000 miles.

Thanks again to a great seller!

veee8

iTrader: (40)

Glad to hear it all worked out for you! That rear has been great for me, and should give you many miles of trouble free service for you, until you start modding that car that is!