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letterman7
18-07-2007, 04:26 PM
I've been trying to research this to no avail. Say you have a standard Beetle tranny, circa '66-68, and you've done nothing to it except change the oil from time to time. Since you don't know the true actual mileage, what is the expected lifetime of a transaxle if one doesn't abuse it? I've heard stories of guys over here with Kubels that are still running OEM transaxles and have had nothing done to them.
It's strictly a curiosity factor for me. I've entertained switching the ring gear for a Corvair motor at one point (and have a reversed tranny for a mid-engine project I've got currently) and always heard it reduces the ring gear life by up to 30% - but what does that actually mean? I can only go 80,000 miles instead of 100K before it needs rebuilt? I'm lucky if I put 5000 a year on my car!

Rick

Peter
19-07-2007, 04:17 AM
I know of cars that have been around the clock at least twice and still going strong on the original tranny. I trashed reverse on my '66 box in '97 and switched to a late 1303 box.

Kym
19-07-2007, 01:48 PM
My 69 swing axel has been hammered and I am still hammering it with 137bhp out of the ej22 subaru. It didn't sound to flash in the diff area and still doesn't but hasn't got any worse and I am on my third clutch.

Sideways in second gear without any body roll, what a blast.

Kym

Peter
19-07-2007, 02:11 PM
I should qualify that by saying I was doing do-nuts and hit reverse instead of second at the time :oops:

letterman7
19-07-2007, 02:48 PM
:? a '69 swing axle, Kym? I thought they all went to IRS by '68?

Anyway, that gives me some hope. When I get ready for an engine swap, all I'll need to do is grind the bellhousing to fit the 12V flywheel. Yes, I'm still on a 6V transaxle - '66 baby!

Rick

Kym
19-07-2007, 10:49 PM
In Australia we where a little behind the US in the change from swing to IRS. But we went early on the discs up front which is where it counts :P Can't have everything.

letterman7
20-07-2007, 01:49 AM
:D Aw, disks were Ghia standard by '67 here, so swaps to the ball joint from end Beetles were an everyday occurance!

Spacenut
20-07-2007, 07:42 AM
I suspect that when you turn over the ring gear for a mid-mount you get a different mesh on the gear teeth which may increase the wear, although I would be surprised if it wasn't possible to adjust the mesh with shims. In fact, don't you set the ring gear mesh preload with shims under the side covers?

That's probably where the stories come from, but there are countless cases of RWD diffs that have been incorrectly adjusted - it's a small, seemingly insignificant (and above all fiddly from what I can gather :D) procedure, so it is often overlooked in the list of big, heavy engineering procedures that surround transmissions.

It still takes a long time for ring gears to wear out though - my '75 Droop Snoot has had a howling 052 for many years (still has from what I gather, although its changed hands a couple of times now), and that was with 170 bhp rally-spec 2.3 litre.

Also you can have that evocative "straight cut" gear whine with no extra cash outlay :D

Lauren

letterman7
20-07-2007, 11:32 AM
:D Straight cuts...if only they made them for the differential! Actually, the mesh has little to do with the wear even if set correctly. The wear comes in at the point where the two teeth meet. The angle cuts between the gears would be backwards, forcing the pressure point on the wrong end of the ring gear bevel. I'm probably over-analyzing the problems, since buggy builders have been doing it for years.

Rick

Peter
20-07-2007, 06:54 PM
Not only were there swing axles about in '68 Rick but they went to longer swing axles in '69 as on my '66 chassis.