Change your lube!

When I pulled the gear case from the main case---OMG---the nightmare began. The gears were stained rusty baby poop brown. There was visible pitting on every surface above the lube line on all of the mild steal surfaces. I called the customer to try and get a history on the car. He purchased it years before and just never changed the gear lube. He was the second owner and frankly it appears the lube was never changed----from 1974 until 2013. That may be a bit long??????

How about a close-up. This is forth-fifth shift collar where the fork rides to move the collar back and forth when you shifting.

Pulled the end cap and what a mess. The shims were OK and interestingly enough the bearings were fairly clean and but cast iron was rough.

I pulled the gear clusters and stripped the pinion. The moister had intruded into the pinion splines and started to pit them. The gears are harder than the pinion splines and they were under the lube so they looked OK----even first was good and the synchro had 43 thousands clearance---I prefer at least 30 thousands minim synchro clearance on a rebuild. This is debatable and depends upon what the final usage plan is for the car.

The cross shaft was not salvageable. The detent cutout on the right side of the shaft was so pitted the removable detent the mounts on top of the small casting attached to the gear case on the right side was ground down and seized up.

Here's a view of the shaft damage where the centering detent rides. I am not using the correct technical terms on everything so if you prefer a higher tec description, let me know and I'll dig up the correct part names.

Here it is from the top.

How about the other side! FUBAR I'll post more of the rebuild later on. It does not get better but I did save it from the scrap heep.

Hi Kirk,
What brand and spec fluid do you recommend for a Zf transaxle?

Shah

mine has been sitting for 30 years and rusting above the fluid line is my big fear. hopefully it can be saved also.

What brand and spec fluid do you recommend for a Zf transaxle?

Shah[/QUOTE]

Shah,

I have always ran Valvoline and have had no issues for 38 years. There are some full synthetics that will not work properly. I have used Valvoline's synthetic blend without issue.

Did you get your cam issue worked out? Hope so.

Kirk

quote:

Originally posted by JFB #05177:
mine has been sitting for 30 years and rusting above the fluid line is my big fear. hopefully it can be saved also.

I would not run it without pulling-er, removing the bottom cover and gear case form the main case. You do not have to pull the back cover---this procedure will expose the all of the gear clusters for inspection. If you have issues, they will quickly appear. The case to case seal is gasket-less (use Yamaha #4) so the only gasket you will need is the bottom cover---some rebuilders do not run a gasket down there---I do. There are shims between the bottom cover and 2 side cover through bolts---keep them in order. There are procedures to the re-assembly I use if you want to try the inspection yourself---drop me a note and I'll get you a list.

Otherwise, depending upon where you are, there are several extremely good trans-rebuilders.

Here is a view of a side cover removed and cleaned. You can clearly see the lube line and rust line from many years of sitting in a non temp controlled environment. The transaxles breathe so they heat up and expel internal air---cool down and suck in external air. Tiny bits of moisture come in---you drive it and blend the water into the lube---40 years of this will become a problem.

Not so good on further inspection. There was not a micron of clearance between third gear synchro color and synchronizer excluding the overall gear condition.

Pulled fifth and found this mess. The thrust washer was totally destroyed and fifth could not be salvaged. And yes the bearing was a tad nasty.

Wisdom taken from the classic B-car movie most Pantera owners can relate to---Christine--- "you can't polish a turd"

Here are the thrust washer and retainer clips all cleaned and ready to toss in the scrap box.

The input gears and associated parts cleaned up. I was able to rebuild second and forth. Third and fifth---not so much. Brake time with my grandson now. Will post more later.

Here is a shot of third gear with the synchronizer installed. The synchro is on the right side of the gear with the tiny teeth. There should be up to 50 thousands of clearance between the teeth of the synchro and the teeth of the synchro collar mounted to the gear. The pushes against the gear collar slowing or speeding up the gear depending if you're up-shifting or down shifting. On ZF's, most of the time the collar is worn out rather then the synchro because of a design defect. The later M1 and the current RBT transaxle use the later better design collar and synchro through 3ed gear. Forth and fifth rarely wear out in the lube fill level is correct and changed a bit more that every 40 years. Now I do not have documented proof the 40 year time period other than the rebuild posted---just IMHO---OMG!.

Here is a comparison between a good third synchro and the worn out third. You can clearly see the gap between the synchro on collar on the left gear.

Here is a comparison view of the lube removed from the trans and a drip of new lube used during re-assembly. The drained lube was water-muddy from the gear blending it had recently had from the car's last drive. The dark drip came out of the differential after it was removed from the main case.

A view of the input shaft center bearing.

Please ask questions or add to the post any experiences you may have had. Counter point are always welcome---always looking for a better way or more usable information for future repairs. Last post until Monday----thank you for looking.

Kirk

Kirk do you think this box was exposed to water at some stage? Maybe the car was stored outdoors for years with the boot removed? Driven off a bridge? Was there water in the lube? I just think this is an exception because this would apply to every gearbox and diff, not just the ZF and I have never seen its like before. It is scary indeed.

I'm thinking water has gotten into the trans maybe via the breather tube not just condensation. I have never seen a trans this bad with the exception on leaving it outside in the rain for a few rain storms open and then put away for years. Maybe I'm just spoiled we do have a "dry heat" you know. LOL

quote:

Originally posted by PanteraWanabe:
Kirk do you think this box was exposed to water at some stage? Maybe the car was stored outdoors for years with the boot removed? Driven off a bridge? Was there water in the lube? I just think this is an exception because this would apply to every gearbox and diff, not just the ZF and I have never seen its like before. It is scary indeed.

I am guessing about the water intrusion. Based on what the current owner has told me, he bought the car from the original owner who lived in Michigan which is where he lives. The car is totally original---including the trans which had the original old clear tubing vent hose. Now here in the summer there can be extremely high humidity with big temp swings from day to night The ZF case has a much larger air space due to the main case size to house the differential. Also the original location of the vent tube was tied to the rear wheel well cross bar and ended up stuck inside the right rear wheel opening. If the car was rain driven, I would imagine the vent tube could pick-up from the right rear tire and as the trans cools, pull in the tube moisture. The second owner says he never sprayed off the trans but if the first owner took it the used a high pleasure washer on or near the side axels, the water car blow by the seals---just guessing on all if this. Regardless you should change the lube at least once a year if your car is in a high moisture and/or humid environment just for safety---IMHO.

As far as other gearboxes, it's logical to assume if the trans is similar in size, material make-up with the case, gears, lube amount and venting end location and length, it should pull water in a similar amount and if the lube has never been changed in 40 years, it may look just as bad from neglect.

Just guessing about all of this---just making the point that out of site in this case can not be out of mind--although if your trans ends up looking like this one you may loose your mind!

Changing the lube was the first thing I did when I received my car a few months ago. I think changing the lube is pretty good advice!

ZF's own service manual says, 'for passenger and racing cars, change the gearbox oil after the 1st 4-5000 km with further changes after 16-20,000 km. The early (blue) Owners Manual says to change ZF lube at 12K, 24K, 36K and 48K, but that note was left out of the more common red Owners Manual.

Note that you CANNOT drain all the lube out of a ZF, even if you remove the assembly and tip it up on its nose in a bucket overnight with the bottom cover off! There will always be at least a pint caught inside, which dilutes any lube changes. Anyone who's ever disassembled a ZF knows to expect a big mess when the cases are separated.

The differential housing---just going inside. There was allot of heavy oil muck inside along with some rust issues. Most of the internals could be saved but it took a bit to clean up.

A bit deeper in the teardown. You can see the damage at this point. The clutches and spider gear pins were bad---I saved the rest.

A shot of the gunk that was inside the carrier. What a mess!

Here is a view of another trans that came in with all of the ring bolts broken and the ring spinning on the carrier. If you have a crack on your main case or bottom cover, it would be best to drain it and pull the cover for a first hand visual inspection before this happens of worse.

A better view of the bolt carnage. I was able to save everything but the dif-carrier and some bearings. The ring gear was OK and it set back up without issue. He was very lucky.

A better view of the carrier damage. This DS-2 carries is no longer serviced and you have to replace the entire assembly--not just the housing---price 2800.00. I was lucky and had a spare---the customer was lucky also.

Here is the ring gear bolt trans back gear case pulled from the main case. This is a good looking assembly and in the condition you want to see when it's opened up.

Back to the rusty one. Here are the gear clusters re-assembled ready to install in the gear case. The 4th-5th max thickness thrust washer had to be ground to size making the final end clearance on the input shaft 8 thousands which is tight.

No school tomorrow for Alex----another snow day here in NW Ohio---what a winter we are having.

More later---thank you for looking.

Here is the main case with the differential installed ready for the assembled gear case to be installed.

Here is the final assembly ready to go back into the car. The outside of the castings were acid cleaned only with very little detail work in an effort to keep the price down a bit. The customer was more interested in function rather than looks.

Another case finish possibility that was bead blasted as another option.

The beat blasted case looks fantastic. Can the aluminum case remain uncoated or will it tarnish badly now that it has been exposed?

Beautiful. Now clear coat it.