LannyL81

Now that I get to actually drive my 81, looks like the pinion seal is leaking.

Is this something I can replace without taking the differential out or is it time to do a complete rebuild of the differential?

Thanks,
LannyL81

CA-Legal-Vette

Need to do mine as well and was wondering if it was possible to do in place.

Twin_Turbo

No, the alu diff has the pinion mount cast in and that prevents access to the seal & yoke, you have to take it out. Taking it out isn't that hard though and a good time to replace any worn bushings.

pws69

I thought you could - hmmmm....

Twin_Turbo

Seriously ... you can't!


It's the one on the right. Now imagine the whole area surrounded by the frame and the driveshaft tunnel between the 2 storage boxes. I have tried it, there just is no way to work in that confined space to get to the yoke

swensonm

So on a 74 you could correct?
Mike

GTR1999

you can on the 63-79 iron diff's just be careful not to overcrush the sleeve when you reinstall the yoke. Look over the procedures first.

...Roger...

I have done it both ways on both diff. and you will be much happier taking it out.It is extremly hard getting the nut loose because of the lenght of extension needed.When you put it back you run the risk of crushing the sleeve too much like has been mentioned.Plus its a good time to clean and paint and inspect other things while their out.

Twin_Turbo

Wow, you actually managed to get it done like that? That's increadible. Did you mark the pinion, nut and shaft to get it all lined up properly after torqueing it down? I had a hard enough time to get the driveshaft off...getting at those little bolts was a PITA and them being 12 points didn't help either.

69427

I definitely agree with your "happier taking it out" and "inspect other things while they're out" comments. I've always disassembled the differential when replacing the front seal. I was always worried about overcrushing the spacer if you can't measure the pinion rotating torque due to the ring gear and halfshafts being connected.

...Roger...

Yes and it was not fun and it wont happen again.I used to do it on the cast iron on a regular basis but the aluminum put me over the edge.I finished it but vowed never again--it was only to do the job according to a flat rate manual (2.1 hours).On the little 12 points I have one by Kent and Moore that I use on a 24 inch extension so my ratchet or impact is up towards transmission.Yes marking the pinion nut made me very nervous and I held my breath for a week after doing it when the customer set out on 200 mile trip.Knowing that if it came back noisy I would have to eat an overhaul.Never Never again they come out!!!!!!

norvalwilhelm

They are ok to do on the car but you need a homemade tool to reinstall the seal. I tried and tried to start a seal in the car but with no luck so I built a nice pinion seal installation tool and it is a 2 minute job to install the new seals.
Yes on a 74 with a homemade tool you can install pinion seals. Doug/carguy4sure borrowed it for his 78 and couldn't believe how easy it was.

KapsSA

Replaced the seals in both of my 79s. Didn't have any problem getting the old seals out or the new ones in. My handy dandy tool (below) and a 3' pipe on the breaker bar made breaking the nut loose and tweaking it back on to my scribe marks easy.
Used 1/8" X 1 1/4" X 36" angle iron($5). Space the holes so that it snugly cradles the flange and bolt it on.

trainmankjm

http://forums.corvetteforum.com/show....php?t=1093346

Check above link. Chg seal last summer takes some time but it worked.
Good luck!!

trainmankjm

https://www.corvetteforum.com/forums...tial-seal.html
Check out this link (it worked for me) definitely doable without a lift
Important to record torque prior to removal.