[Technotron101]

Hi all, just looking for some expert insight into some diff centres I have.

So I've pulled my front centre out, as it's seizing and making all manner of amusing noises (identified as pinion bearings, all good) except the replacement centre I've sourced doesn't match, visually. I'm now not sure (as my car is a bitza anyway) which is standard, front vs rear etc etc.

For reference I'm WT, and all three centres I have are 3.7, so no worries there.

The centre I pulled from the car is a 4 pin carrier, and the carrier has the crown wheel bolted up on one side, and some sort of cap or flange bolted up to the other side, and the whole carrier is basically cylindrical (see attachment)

Attachment:

image000000.jpg

My new-to-me centre is a 2 pin carrier, but the carrier is cast and is all shaped with windows to the spider gears and such, with the crown wheel bolted to the other side.

Attachment:

IMG_20190428_164819095.jpg

They both have "front" side gears, which I think are 26 spline?? As I'm running standard front axles and CVs which mesh with both centres.

My question then is which is which. Is the 4 pin carrier a rear that's had a side gear transplant to suit the front axles? Did all wt sierras come with 4 pin carriers front and rear? Just rear? Are all wt fronts 2 pin?

Just curious as to what it is I had and am putting into my car. Thankyou!!

[greenzook89]

WT fronts are 22 spline 2 pin 3.7 ratios

All Sierra front axles are 22 spline.

Possibly you have a NT/WT bitsa front centre.

[Technotron101]

Thanks mate, helps clear things up a bit. Are WT rears 4 pin?

Does the image of a the 4pin carrier look standard or aftermarket to you?

[greenzook89]

Yeah the 4pin looks to be same as factory rear. 26 spline rear axles however.

[Technotron101]

Yep that's what I figured, as the rear was originally a limited slip, and the previously owner probably swapped side gears and dropped the original rear into the front for the four pin carrier.

Thanks, saves me some head scratching haha

[303zuke]

You would probably already know if you've pulled the 4 pin carrier from the vehicle, but have they used the 4 pin carrier in the front to install a Lockrite locker or similar? Auto lockers can be installed into a 2 pin carrier but they work much better in a 4 pin carrier, and this is the usual reason for fitting one in the front diff.

SJ50 WT's (plastic flares) have 3.9 gears and 4 pin fronts as factory.

[Technotron101]

Ahhhh well maybe (I am a sj51 widetrack) it was fitted as factory?? By then it's 3.7 so maybe not.

I'm fairly certain it's an open centre, the side gears spin freely turning the opposing gear, and it displayed no locking behaviour when I drove on it.

The rear had an lsd in it, so that's why I figured it must have been swapped from the rear. Interesting anyhow