Oil leak at GTC axle

Moderators: 330GT, abrent

Jumprun
Posts: 276
Joined: Wed Aug 01, 2012 6:28 pm
Contact:

Re: Oil leak at GTC axle

Post by Jumprun »

Well, I got the side covers off, it took loosening the differential cover nuts and a few well placed whacks with a rubber mallet to loosen things up. The seals were still pliable but very worn out. Of course I was careful with the shim plates and used a very light coat of sealant when I put the covers back on.

I then removed the shifter cover to replace the gasket, inspect the guts, and make sure the shift finger was in the right position for reassembly. I understand now what Tom was saying that it was intuitive how it works. I also made a strap as Tom did to hold the three small springs in place while the cover is off.

I inspected the innards and I'm happy to say all looks well with no visible scoring or chipped gears. I then cleaned out the sump, looking for chunks of metal, all I found were a few small flakes and moderate metal hair on a magnet I passed around. Since the car was shifting reasonably well before with no weird noises I'd say I'm good to go.

Tom Yang mentioned a shift rod O-ring but the parts manual does not seem to show this seal, it would have to be in the bore. Anyone know if there should be a seal?

I also have a question about the paper element filter on the drain plug, how is this replaceable? the parts manual does not show a separate part from the plug or how it would come apart.

Regards from SoCal, Tom M.
DWR46
Posts: 621
Joined: Tue Sep 22, 2009 8:23 pm

Re: Oil leak at GTC axle

Post by DWR46 »

Tom: The drain plug should have a brass/copper screen filter made as part of the plug. There is NO paper filter on the drain plug.
Jumprun
Posts: 276
Joined: Wed Aug 01, 2012 6:28 pm
Contact:

Re: Oil leak at GTC axle

Post by Jumprun »

Thanks for the reply Dyke. My plug does not have a brass screen filter, it has an accordian type paper/fiber filter, it looks the part, much like a fuel filter. Maybe I should replace it with some fine brass screen, as it does look beat up, or maybe my favorite supplier has the correct replacement.
User avatar
tyang
Posts: 4060
Joined: Wed Nov 27, 2002 10:28 pm
Location: New York
Contact:

Re: Oil leak at GTC axle

Post by tyang »

Hi Tom,

Look inside the sleeve in the transmission cover that the shift rod slides. There is an o-ring that keeps the gearbox oil from leaking out the shift rod. It has to picked out with a small pick tool. It's really a judgement call here. Normally, I would simply replace the rubber o-ring for a fresh one, but a new one we installed recently leaked! The dimensions are critical, so make sure the replacement is exactly the same as the one you're replacing! With some cars, it's nearly impossible to pull the side plate off the transmission without removing it because it's part of the transmission mount to the chassis. With the PITA of removing the side plate and positioning of the shifter finger correctly, now is the time to make sure this little 2 cent seal is working!

I'm glad you're making progress!

Tom
'63 330 America #5053
Jumprun
Posts: 276
Joined: Wed Aug 01, 2012 6:28 pm
Contact:

Re: Oil leak at GTC axle

Post by Jumprun »

Tom, thanks for the encouragement. Ok, I believe I understand where the seal is. It appears I'll need to disassemble and remove the shift finger from the rod to get to that O-ring. It's interesting how the parts manual shows nothing of a sort sealing that rod, and I can feel no drag on it indicating any seal, of course it could be so worn as to produce no drag. As a point of interest, the early Daytona parts manual, which has a very similar transaxle as the GTC, does show a sealing ring on the rod (red circle). I've also learned that since my car is a later GTC, it shares some features of the Daytona and 365 GT 2+2 that are not on the earlier cars.
GTC.gif
GTC.gif (35.39 KiB) Viewed 9327 times
Daytona.gif
Daytona.gif (35.81 KiB) Viewed 9327 times
Thanks everyone for the advice, I'll let you know what I find.

Blue Skies, Tom
Timo
Posts: 216
Joined: Thu Apr 13, 2006 8:56 pm
Location: Riverside, California

Re: Oil leak at GTC axle

Post by Timo »

tyang wrote:... o-ring ...,... dimensions are critical, so make sure the replacement is exactly the same as the one you're replacing!
This would apply only if the one being replaced is/was determined to be correct to begin with.

Otherwise, results can easily lead to following:
tyang wrote:...but a new one we installed recently leaked!
Timo
Colin Angell
Posts: 49
Joined: Tue Apr 13, 2004 1:11 pm
Location: Worcestershire, England
Contact:

Re: Oil leak at GTC axle

Post by Colin Angell »

Hi Tom
Sorry for the late reply, but unfortunately I don't have an up to date answer to your question about synchro rings. I am not sure where you have been finding problems, but my first call would probably have been to Ferrari UK parts, or you could try Piet Roelof who certainly has 275 rings (not sure if they are the same) and is always reliable.
Sorry I can't be more helpful
Colin
User avatar
tyang
Posts: 4060
Joined: Wed Nov 27, 2002 10:28 pm
Location: New York
Contact:

Re: Oil leak at GTC axle

Post by tyang »

Timo wrote:
tyang wrote:... o-ring ...,... dimensions are critical, so make sure the replacement is exactly the same as the one you're replacing!
This would apply only if the one being replaced is/was determined to be correct to begin with.

Otherwise, results can easily lead to following:
tyang wrote:...but a new one we installed recently leaked!
Hi Timo,

The original one was hard as a rock and was leaking as well, but the first replacement was slightly different. Comparing the old one with the final one, we found the exact replacement, but what you're describing has also happened!

Tom
'63 330 America #5053
User avatar
tyang
Posts: 4060
Joined: Wed Nov 27, 2002 10:28 pm
Location: New York
Contact:

Re: Oil leak at GTC axle

Post by tyang »

Hi Colin,

No worries. I'm just doing an informal survey to see what other shops have used.

Tom
Colin Angell wrote:Hi Tom
Sorry for the late reply, but unfortunately I don't have an up to date answer to your question about synchro rings. I am not sure where you have been finding problems, but my first call would probably have been to Ferrari UK parts, or you could try Piet Roelof who certainly has 275 rings (not sure if they are the same) and is always reliable.
Sorry I can't be more helpful
Colin
'63 330 America #5053
Timo
Posts: 216
Joined: Thu Apr 13, 2006 8:56 pm
Location: Riverside, California

Re: Oil leak at GTC axle

Post by Timo »

tyang wrote:
Timo wrote:
tyang wrote:... o-ring ...,... dimensions are critical, so make sure the replacement is exactly the same as the one you're replacing!
This would apply only if the one being replaced is/was determined to be correct to begin with.

Otherwise, results can easily lead to following:
tyang wrote:...but a new one we installed recently leaked!
Hi Timo,

The original one was hard as a rock and was leaking as well, but the first replacement was slightly different. Comparing the old one with the final one, we found the exact replacement, but what you're describing has also happened!

Tom
Hi Tom

I was merely offering alternative perspective for assumption which I've learned (hard way) never to rely on.
Timo
User avatar
tyang
Posts: 4060
Joined: Wed Nov 27, 2002 10:28 pm
Location: New York
Contact:

Re: Oil leak at GTC axle

Post by tyang »

Hi Tom

I was merely offering alternative perspective for assumption which I've learned (hard way) never to rely on.
Agreed! I often spend more time figuring out what the last guy did than fixing the actual problem!

Tom
'63 330 America #5053
Jumprun
Posts: 276
Joined: Wed Aug 01, 2012 6:28 pm
Contact:

Re: Oil leak at GTC axle

Post by Jumprun »

This is the wrap up post and summary of my transaxle work.

The installation was twice as difficult as removal, an assistant was mandatory.
There was an o-ring seal in the shift rod bore that is not shown in the parts manual.
The rear cover needed to be loosened to remove the side covers.
My drain plug filter was not wire screen, instead it was cloth fiber, I examined it very carefully and I don't believe it was home-made job so I cleaned it up and reused it.
I replaced the side seals, front seal, shift rod seal and the shift cover gasket.
I cleaned the sump out and inspected the gears and shafts.
I repaired the back up light switch.
I painted the case silver.
I refilled the case with Redline MT-90 and some LSD additive.
The car shifts much smoother and faster, especially cold.....that juice is trans rebuild in a bottle.

Thanks for all the encouragement, I hope this thread helps someone else someday.
Tom Martinez, in SoCal
BobA
Posts: 103
Joined: Tue Nov 12, 2013 7:36 pm

Re: Oil leak at GTC axle

Post by BobA »

I have been following this post with interest even though I own a GTE. However the one item that pops out is the mention of a cloth filter on the drain plug. Since there is no flow, what would the filter do? It would seem that a magnet epoxied to the drain plug would at least capture magnetic debris and keep it out of the normal splash circulation. Am I missing something here? Thanks. Bob
Jumprun
Posts: 276
Joined: Wed Aug 01, 2012 6:28 pm
Contact:

Re: Oil leak at GTC axle

Post by Jumprun »

BobA wrote:I have been following this post with interest even though I own a GTE. However the one item that pops out is the mention of a cloth filter on the drain plug. Since there is no flow, what would the filter do? It would seem that a magnet epoxied to the drain plug would at least capture magnetic debris and keep it out of the normal splash circulation. Am I missing something here? Thanks. Bob
The gtc has an oil pump
Post Reply