ZF Leak

I believe you are going to have to partially disassemble the trans to replace the seal. It can be done at home with patience and thought.

Don't overfill ,3,4 liter .

easy to fix on the passenger side, on the drivers side, you gotta pull the tyranny out. Sorry.

quote:

Originally posted by Quickitty:
Just trying to get this ZF installed after having restored the car. Finally got everything together and the ZF is leaking pretty bad at the drivers halfshaft where axle comes out of the ZF. There is a seal that is soaked in fluid.
about 1 drip every 45 to 60 seconds.
What is involved in changing this seal. Had the tras in and out so many times I could do it blind fold, just never had it apart.
Suggestions??

The passenger side on mine leaks. If it's "easy" I'm game to fix it. Can you give more detail?

Steve

They have a step by step process posted on Pantera Place.
Does anyone have a pic of the pliers needed to get the ring clip off the axle?
sounds to be a pretty specialized tool

Quickitty; The ZF manual does not list a special tool for the snap ring, just references "long nose" snap ring pliers.
As much as you may resist, I'd suggest the blindfold goes back on and the transaxle out for ease of having it on a work bench.
I've attached a schematic of the transaxle portion you will be working on which you may already have.

Basically, to change an inner stub-axle seal, the side plate must first come off. And there are two long bolts under the ZF that go side-to-side through bosses in the side plate AND lower cover. So, out comes the tranny.... Once out, BIG snap-ring pliers (for leverage) are used to remove the larger snap-ring. Note also there are shims in the bearing stack that must be returned exactly as they were because they set side gear preload. Losing one will cause howling from the ZF under power. And the thickness of the side-plate gasket is also part of the preload stack; if yours are torn, real ZF gaskets are cheap- do not try saving $3 here! All the vendors sell them.

Its possible to unbolt the ZF, slide it back, roll it on one side and do all the work in an awkward, uncomfortable position leaning over in the engine bay. Best to use a crane or a couple of good buddies, lift the 155 lb lump onto a bench and have some hot coffee handy. Your back will thank you the next day!

Thanks Bosswrench
I think that is the plan. I will unbolt the trans from the bell housing, leaving the bell housing on the engine, then angle the engine up slightly. The trans will slide back and out. Done it a couple of times, got it down pretty good.
Always been a bit nervous about opening up pandoras box....I mean the ZF...same diff.
I have convinced myself that this does not count as actually "opening" it up, more like tinkering around the edges.....right?

quote:

..I will unbolt the trans from the bell housing, leaving the bell housing on the engine...

I was thinking there are two bolts/studs internal to the bell housing

Right, JFB- I would also pull the bellhousing. In fact to slide the ZF back & roll it 90 degrees, you've done 98% of the work needed to pull the thing out on a bench where you're more comfortable. The only savings in doing it this way is, you don't need to bother your friends or rent an engine crane, and the diff lube may not need to be drained. While you're in there tinkering, check for vital ring gear bolt safety wire & add as req'd.

I've done the slide-back thing only to replace the clutch & other things in the same area.

quote:

I was thinking there are two bolts/studs internal to the bell housing

He has a dash 1 ZF. Only four nuts to remove.

Here's a pic from one of his posts.

John

Bosswrench, your comment about the howling on acceleration has got my attention. That is the problem I'm having and I've searched all over trying to find information on this.
My car shifts fine but just makes noise while you have your foot on the accelerator. Stops the instant you take your foot off. A previous owner has been into the transmission because it's safety wired, so did they change seals at the same time and leave out the shims or is the stack-up wrong?
I would like to thank this forum for all the information it has provided.
Thanks..

Sad to say Mr Rat, there's only two possible reasons for diff-howling in any car: one is improper preload in the assembly (shims etc). The other is simple wear. Both require R & R of the diff and both really require an expert with special tools to determine which it is and to properly fix it. Spare parts for this 43-yr-old transaxle are few, and when used pieces do come available, they're apt to be VERY used.... I've seen noise abate a little by substituting 140-wt diff-lube for the recommended 75-90 wt. But there, you're adding organics for missing metal and it won't last too long. It also eats horsepower and heats up more. In the bad ol' days, a cup of Quaker Oatmeal was sometimes poured into diffs to quiet them long enough to sell a noisy car.... If you change diff lube yearly, as recommended, and it doesn't drain very fast (or at all), that's a red flag.

If it IS plain ol' wear, the ring gear and pinion are machined as matched sets, with the set-up info etched into each ring gear periphery. So when a 'spare' used ring gear from another set is substituted into a reconditioned ZF, it can cause howling if you don't know what you're looking at. Does yours make noise on acceleration or deceleration? That will determine whether the problem is on the power side of the teeth or the coast side (assuming the preloads are correct). Sometimes, judicious shim-changes to reposition the gear-tooth contact points can reduce wear noise.... for a while.

Two recommended shops: RBT Transmissions in the Los Angeles Basin is the only source for new ZF gears on the planet. And Kirk Evans' 'Amerisport' in Ohio is known to have resurrected some hopeless-case ZFs. There are other shops world-wide, but you're on your own with them.

Bosswrench
I completely agree that taking the trans out with the bell housing is easy, except, I am physically able to lift the gear box out of the car and put it on a bench. Ad the weight and bulk of the bell housing, then I have to get my engine hoist out. I prefer to have the gear box on the bench where I will not have to fight to keep my big ass in the engine bay for any length of time
Just a question about Riverrats trans. Could worn or bad bearings be causing the howling under load? Thought I remember reading something about that somewhere, but not sure.

Ron McCall in Md. is also highly recommended.

Bearings indeed do howl- just before they seize solid- but the fact that his noise seems to be under acceleration, stopping when under coast kind of points away from a bad ball bearing. And you need to jump through the same hoops to get to a leaky seal or worn ring/pinion as to one of the bearings...

Got her out and open.
Must say, was a bit nervous opening my first ZF.
Had visions of Indiana Jones when the Germans opened the Ark of the Covenant. Stream of Fire, Face Melting....perhaps that will come when I try to put it back together. Or maybe I was spared because I had my eyes closed the whole time Yea, lets go with that.
So, I need some help with this stupid question that came to mind. I pulled the leaky axle, (seals are on their way and should be here by Saturday). I am guessing that if I pull the other axle out, there will be nothing to keep that big ring thingy from falling into the belly of the ZF. So, do one side at a time??? I see the C ring clips, looks easy enough to pull and remove the seals. Any pit falls I should be on the look out for?? If not, this looks pretty easy.
Also looks like someone has been here before, all nice and safety wired.....Cool!!

Safety wired

FWIW, Lloyd told me that all of the dash 1 ZF's were safety wired from the factory.

John

You can pull both axles out and the ring gear too. Just put it back the way it came out lol. Looks scary but not that bad if you take your time.

These ZFs are pretty cool.

You can look on the Ring Gear (and on the pinion) and see the date that the thing was assembled / matched (in the German date format).

Mine was set up on 12/22/1972.

Rocky