Inspecting DIFF PIN- no transaxle disaasembly needed

[wolfman]

As many of you know by now, the open differential in "S" series transaxles can have issues with it's DIFF pin. There IS a way to give it a basic visual check WITHOUT removing the transaxle or doing any major disassembly.

Proceed as follows:

Jack up the FRONT of the car until BOTH front wheels are off the ground and support it with jack stands.

Set the PARKING BRAKE and CHOCK THE REAR WHEELS!

Open the hood and locate the VSS (Vehicle Speed Sensor) ....My USER GALLERY has PICTURES of where this is on BOTH manual and automatics..

Unplug the VSS electrical connector and unscrew the VSS from the transaxle.

Place the transmission (manual OR automatic) in NUETRAL

Shine a BRIGHT flashlight into the VSS mounting hole at about a 45 degree toward the PASSENGER SIDE of the car.

While looking into the VSS mounting hole with your flashlight (at about a 45 degree angle) have an assitant SLOWLY turn the driver's side wheel in either direction. As he (or she) does, the DIFF piin will come into view. It will appear as a SHINEY round silver circle in the GREYISH cast housing that is rotating before your eyes.

Have you assitant continue to SLOWLY turn the wheel until you see the DIFF pin TWICE (both ends)

What to look for:

The DIFF pin SHOULD be FLUSH with the housing on BOTH ends. If you discover that it is either protruding slightly or slightly below the casting, the retaiing roll pin has most likely FAILED and you are living on VERY borrowed time.

If it IS flush on BOTH ENDS, you are fine.

This is not all bad news however. STOP DRIVING THE CAR! If you remove and disassemble the transaxle now, you are looking at a simple repair (I recommend WELDING the pin to the housing...again see my user gallery) and not transaxle replacement. Push your luck however, and you can COUNT on catastrophic failure that will require the replacement of the transaxle.

[geartooth94]

i wonder if a supremely expert welder could get in there WHILE THE TRANS IS STILL IN THE CAR and weld that little bugger in there? how big is the hole that contains the VSS ?

[2SL's&1SC]

Wolfman: If the pin isn't flush, would it be possible to tap it back from the other side and apply some J B Weld to help hold it?

[myoung]

As someone who's blown two of these up, one welded, I wouldn't try either of the workarounds proposed above.

The welded pin weas only surface welded, and the welds broke, thus causing my second failure. As always, your results may vary, but I caution against this.

The third transmission, which is in the (wrecked) car right now, we tried a little different welding approach. We tapered both edges of the pin, and then also ground around the entry holes in the actual diff, to create a channel of sorts around the pin. This gave the weld a little more strength. While there's no way to say definitively that it is going to hold up better, the transmission is still intact.

I know you guys are looking for workarounds to dismantling the trans, but if you do it now, and do it right, you save yourself $300+ on a new (used) transmission.

[Saturn-Eh!]

Originally Posted by geartooth94

i wonder if a supremely expert welder could get in there WHILE THE TRANS IS STILL IN THE CAR and weld that little bugger in there? how big is the hole that contains the VSS ?

Theoretically it could be done, but the only grounding point available for the welding would be through the transaxle case. the only way for the diff to conduct through the case would be through the carrier bearings, so you would risk arcing at the bearing contact patches. You would ensure that the diff pin is safe, but at the expense of severly shortened bearing life...

[strongboy2005]

When you remove the VSS is tranny fluid supposed to come out?

I removed the little connector and then used an adjustable wrench to remove the large nut and tranny fluid began pouring out pretty profusely, is there something wrong or was this just not mentioned in the write-up?