Diff Leaking

[maytag]

Hey y'all:

got a good-sized puddle under the car. the only wet spot I'm finding underneath (just reaching under, haven't jacked it up yet) is right at the drive-shaft flange / yoke flange. And that'd be about the right place for where the puddle's at.

What's involved in replacing that pinion seal on these cars?

[Fi8spider]

Fairly straight forward maytag unless you want to do it right which is to reset the preload and backlash adjustment between the crownwheel and pinion, a new collapsible spacer (also known as crush tube) will be required for this job.

If you just want to change the pinion seal and chance it with the preloads it can be done but I would suggest that you understand that incorrect meshing between the CW and Pinion can lead to premature wear.

I had mine done at a Fiat workshop a year ago as he has the special tools to measure the preloads, I removed and replaced the diff centre myself and he did the service which included all the parts (seal, crush tube, rear bearing thrust washers) he charged me about $150. I had a whine in my diff before the job which wasn't why I did it but because the pinion seal packed it in after a track meet. Since having the preloads done right the whine has disappeared, I'd say either the diff needed the service or the PO did a short cut job last time the pinion seal failed.

[maytag]

figgers......

[Fi8spider]

Don't dispair mate..Parts wise everything is avaliable, probably $50 tops.
The diff centre style isn't something special to Spiders so I dare say you'd have a driveline specialist in the area that could do the preload for you.
How long would it take a guy like you to pop the rear axles and remove the centre? An hour and a bit? Two hours if you add a couple of refreshing ales along the way?

[ventura ace]

If it's leaking at the flange, it may not be the pinion seal, but rather down the splines between the pinion shaft and the flange. I changed my pinion seal 3 times before a realized this! A giveaway clue: If you part the flange from the drive shaft and find it wet inside, it's coming from the splines. To remedy, remove the big nut (mark it first in relation to the flange so you can put it back in the same position), remove the flange, clean everything thoroughly, put silicone RTV on the splines (both pieces), install flange, put more sealant on the threads and between the nut, washer and flange, tighten the nut back to where it was before, and it wouldn't hurt to give it just a tad more tightening, then reconnect the drive shaft.

Alvon

[Fi8spider]

But the splines are exterior to the pinion seal, for the spines to be wet means that the oil had to pass through the seal. I can't see how silicone can fix or stop a weaping seal. Maybe on the last fix you positioned the seal a little deeper or forward of the old contact surface on the pinion which could have been scored from wear.

Yes you can mark the position of the pinion nut before removing it and count the turns out, this is the short cut. You have to restake the nut once in place so a new one would be a good idea as the old one could get damaged when unstaking it.

[manoa matt]

The splines are internal to the seal. Oil can and will bypass the splines and collect in the pocket between the the driveshaft yoke plates that are held together with the 4, 13mm bolts. Also a good idea to place RTV on the mating surfaces of those two plates.

[Fi8spider]

Ok. This has convinced me to pull out my parts diff and have a look at the set up. I can see the area ventura and Matt have pointed out and I would have thought that the torque needed to keep the flange onto the pinion would have been enough to stop oil travelling up the splines but obviously not. Very good thing these forums .

I still question the retorquing of the pinion nut without doing the preloads as being a little hit and miss.

Thanks for the added education fellas.

[donerehart]

I'm so thankful for this website! Has anyone heard from manoa Matt lately? I haven't seen any posts in a while...