Oil leak at GTC axle

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Jumprun
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Oil leak at GTC axle

Post by Jumprun »

In the never ending battle against oil leaks I'm now seeing a significant one at the transaxle axle half shaft where it exits the case. Looking carefully at the GTC parts manual it appears there is a rubber sealing ring, (tav.21, item 19, P/N 4560/10) that keeps the oil in in it's place. I've previously removed the axles/u-joint to replace the rubber boots and repack the bearings so I'm familiar with that job but It appears I'd also need to remove the internally splined drive flange (tav.21, item 11, flange per semiassi) and maybe the side cover? (tav.21, item17, coperchio laterale) Has anyone experience with this job and what I might expect other than oily greasy hands?

Blue Skies, Tom in SoCal.
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tyang
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Re: Oil leak at GTC axle

Post by tyang »

Hi Tom,

Once the splined drive flange is removed with an impact gun, you should be able to pop the seal out if my memory serves correctly.

Tom
'63 330 America #5053
Jumprun
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Re: Oil leak at GTC axle

Post by Jumprun »

Hi Tom, After closely examining the shop manual cut away diagram of the GTC transaxle and having the new seals in hand it appears that the side covers need to be removed in addition to the splined drive hub because the seal is installed from the inside. I also referenced your blog of 2/27/11 regarding leaking seals on a Daytona, which looks very similar to the GTC.

Ok, I removed the center bolt with an impact socket, no problem. I removed the splined hub, no problem. I removed the 8 nuts holding the shimmed side cover on, I tapped around the edges to see if I could loosen it enough to get two screwdrivers under the flange to gently work it out of the case but had no luck. I wonder what the diametrical fit of this side cover is to the case bore? slip fit? light press fit? I don't see an obvious way to get a puller on it because there is nothing on the flange to grab onto.

Any ideas or tricks to get the cover off? This cover would need to come off first if one needed to remove the rear differential case cover as the stud pattern spans the split line. Am I way off base? I can post the cut away diagram but not till tomorrow.

Best Regards, Tom in SoCal
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tyang
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Re: Oil leak at GTC axle

Post by tyang »

Hi Tom,

My blog certainly helps job my memory! I have to think back to which car had the seal pop out from the front side. 400? I'll have to check.

It should come out, but supports the bearing on the ring gear. I'll get back to you on this.

Tom
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Jumprun
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Re: Oil leak at GTC axle

Post by Jumprun »

Here is the exploded diagram, cut-away diagram and the disassembly instructions, which reads that the diff. cover 47 needs to come off before the side covers, 44 and 45 but the diff cover has studs in the side that the side covers attaches with. I suppose that the diff cover, 47 can just be loosened to free up the side covers or the side studs would need to be removed.
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afwrench
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Re: Oil leak at GTC axle

Post by afwrench »

Hi Tom, I would use a brass drift and "gently" strike the plate between and just internal to the studs all around.This might deflect the plate just enough so that spring back may pop it up enough to get a grip on it.Standard procedure on large truck axles bolted externally to rear wheels. Good luck. Mike
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DWR46
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Re: Oil leak at GTC axle

Post by DWR46 »

It is not easy to get the side covers off. Usually we can work a knife blade under the cover at numerous places and slowly start to move the cover. Be VERY careful to not damage the shims (items 36,37) between the cover and the case. These shims set bearing clearances and are specific sized for each transaxle. When you reassemble the covers, use a smear of Locktite 518 on each side of the shims to make sure they do not leak. Good luck.
Jumprun
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Re: Oil leak at GTC axle

Post by Jumprun »

Tom's blog of 2/27/11 inspired me to just go ahead and pull the transmission, considering I've also got a leak at the input shaft. It's hard to believe there is aluminum under all the gunk. I took me a few hours to pull it by myself, it reminded me of pulling an old Porsche engine out all alone, not terribly difficult to remove but having a helper to install is the way to go.

Once on the floor I went after those side covers to no avail, knives, chisels, screwdriver, etc. have not been able to get a gap started to work the cover off. I'm thinking I'll need to loosen the Diff. cover to free up the sides a little. Of course comments, ideas or commiseration is always welcome.

Blue Skies from SoCal,

Tom Martinez.
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tyang
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Re: Oil leak at GTC axle

Post by tyang »

There could be some tension on the plates from the rear diff cover, so loosening the nuts may help.There could be some corrosion locking the plate in place with the steel studs. Penetrating oil can't hurt.

Since the transaxle is out, make sure the shift shaft seal isn't leaking because it's a lot easier to replace this little o-ring now. Just make sure you get the correct o-ring that properly seals against the shaft and the housing.

You know about putting the transmission in 2nd gear? When removing the transaxle, you must put the transmission in 2nd gear. There are witness marks on the shifter coupling that line up with marks on the transmission case where the shift shaft enters the side plate. This keeps the shift finger from falling out of index with the transmission internals. If you didn't do this, you can still put the shifter in the car into second, but you'll have to feel to make sure the shifter on the transmission is still where it's supposed to be when it's in 2nd gear. Worse comes to worse, you'll have to remove the side plate to see what's going on. If you're confused, I'll try to explain this better.

Good luck.

Tom
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Jumprun
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Re: Oil leak at GTC axle

Post by Jumprun »

Yes I think I'll try loosening those rear cover nuts but since the rear cover side studs are captured by the side plates there won't be much movement there, I have a feeling I'll need to remove some side studs.

Tom, thanks for the tip about the shifter O-ring, surely it needs replacing.
Oops, I didn't know about the 2nd gear trick, I left it in neutral, the same way I did when disconnecting and moving the trans back a couple of times for the clutch job. Can I check if I have a problem now and correct this while I'm still on the floor?

Tom, thanks for your time and experience. I'll post progress of my relatively minor travails for posterity and to possibly help others.

Best regards from rainy SoCal
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Re: Oil leak at GTC axle

Post by Colin Angell »

Hi, My experience is that you have to loosen the rear cover before you will be able to remove the side covers. That is because the transaxle case, which is split on the centreline of the drive shafts, is an interference fit with the boss on the rear of the side covers. As already mentioned be very careful with the shims under the side covers, which are critical to proper set up of the differential. Good luck
Jumprun
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Re: Oil leak at GTC axle

Post by Jumprun »

Colin, thank you for the reply, it confirms my plan to loosen the nuts.
Oh, I'd also like thank you for the advice and procedure you gave me last year on how to move and time my cams, getting the sprocket and chain back on the cam shaft end was a challenge but worth the satisfaction to get it right.

Tom M.
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tyang
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Re: Oil leak at GTC axle

Post by tyang »

Hi Tom,

Yeah, the way the shifter works, the finger that engages the forks can slide out of index when in neutral if it's not captured in 2nd gear. Since you're probably going to replace the seal on the shifter, you'll be removing the plate and it'll become obvious what I'm talking about. It's sometimes very hard to describe, but it will all become clear when you take it apart. Make sure you don't lose the springs that are held in place by the cover plate! So much to know, and a lot of traps, but we'll get you through it!

Tom
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Colin Angell
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Re: Oil leak at GTC axle

Post by Colin Angell »

Hi Tom

Thanks for your nice words. Please see a couple of photo's showing my transaxle on a stand and also one which shows the case split open and you can clearly see just how deep the side plates are and why the friction build up is such that they are difficult to get off. I assume that apart from the leak you are happy with the mesh of the crown wheel and that you don't have any noises from the back end, but if you do then obviously you could sort that at the same time. If everything is fine then make sure that you take meticulous care of the shims and replace them in exactly the same place when you re-assemble.
Good Luck
Colin
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tyang
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Re: Oil leak at GTC axle

Post by tyang »

Hi Colin,

Where are you guys getting your sychros these days? We had a hell of a time finding a set that worked well and from what we found, they're not all created equal!

Tom
'63 330 America #5053
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