TheSamba.com :: View topic - Lets Play Name That Part

Fri Jul 29, 2016 7:39 pm

So I have had the car for about 6 months and have put less than 1000 miles on it. Basically I have been slowly bringing her back to life and enjoying putting around in the car. Its a 1960 Ragtop with original motor and tranny that was parked and sat for about 30 years. It is a non-syncro 1st, and seems to work fine. upshifting 3rd to 4th will occasionally produce a very slight grind, but not consistantly, and not very obvious. I checked the transmission oil level when I first got it but this is the first opportunity I have had to drain and replace with fresh oil. When I pulled the forward drain plug, this was attached to it. It looks almost a roller for a bearing, but not quite, otherwise could be some sort of dowel pin? If anyone knows the insides of these transmissions, maybe you would venture a guess?

Thanks for playing :D

Fri Jul 29, 2016 10:31 pm

It looks a little small, but it might be a locating pin from the transmission case halves. Unlikely, but if too small and loose it could have fallen inside the case during assembly. Are the ends of the pin nicely finished with straight ends? Diameter = ? Those drain plug magnets are a blessing....

Sat Jul 30, 2016 6:46 am

The ends of the pin are not smooth, one end looks like it has evidnece that it stress failed, almost what you see in internal engine stress failures (see photo) and the other end is just somewhat rough 9But not the same "failure" fingerprint...

Sat Jul 30, 2016 6:58 am

It looks like part of the pin that would hold the cross shaft in the differential the spider gears ride on. If it's the original Split Case trans, the only way to get into the differential area is to open the halves of the case. If that in fact is was it is, bad things are going to happen when the shaft it was holding finally comes out, so I would stop driving it.

Addition: Although this is an IRS Differential, this is the pin I was referring to. It gets driven through the shaft above it in the picture to lock it from coming out of the diff. The IRS pins were actually roll pins, but the Swing Axles had solid pins that were peaned over on the end. Picture courtesy of bartman in the gallery.

Sat Jul 30, 2016 7:44 am

measure the dkameter and post it. if diameter matches what others find for the retaining pin, then that is good evidence as to what it is, was. if it is that retaining pin, tranny repair would seem to be prudent thing to do.

good luck

Sat Jul 30, 2016 8:29 am

I don't have one opened up otherwise I would look. In the 52 -57 Bentley manual I only see two pins. One holds the Reverse sliding gear shaft and the pins mentioned on the differential.

The reverse sliding gear shaft pin is only accessible after splitting the case and removing the main shaft. The pin is held in place by the rear (engine side) main shaft ball bearing. This is shown on page 5-5 picture 8. There is no way this could come out in normal operation. The end of the shaft would have to have broken off to allow that pin any chance of coming out. Even then it would probably required part of the case to have broken off too and you would also have the end of the shaft in there too so I think that is extremely unlikely.

The other pin is referred to as the Lock pin in the Bentley manual on page 7-1 on the diagram for the differntial.

The weird thing is that you said that you found this on the forward plug. That would be the transmission side. Due to the fact that the transmission side is separated from the differential side on the case casting with only a few fairly small holes for oil to reach the differential side from the transmission side, it would be extremely difficult for part of the differential pin to make its way to the transmission side.

This is a '54 transmission. The pin went through a hole in the reverse sliding gear shaft and was a hollow pin.

Later pins appear to have been solid dowel pins.
This picture shows both pins quite nicely

'58 and later transmissions switched from a roller bearing to a needle bearing pinion bearing. I doubt that is a needle bearing "needle". Even if it is then that means that the bearing has started to break apart. Pretty unlikely but that is the only way it would be loose. The transmission would make one hell of a noise and again you would have other chunks in the old if that is where it came from.

If it were me I would not drive the car any further and would split the transmission to find out what is going on. The bad thing is that the split case gasket sets are no longer available so that is a definite issue. If that is part of the differential pin.

I guess it is possible that it was put there intentionally to help the magnet catch more material. Seems very unlikely however we have all seen some really weird things done to cars by previous owners.

As suggested it could also be something that was accidentally left in the case during a rebuild. It could be the reverse sliding gear shaft pin that got lost in the case during a rebuild and the mechanic just left the pin off the reverse sliding gear shaft. That wouldn't be good either.

Sat Jul 30, 2016 8:30 am

I don't have one in front of me, but I would say the diameter would be around 6mm, or 1/4 of an inch.

Unless you are going for a factory restored vehicle, it will most likely be less expensive to get a rebuilt 4.37 trans with short axles from the mid 60's to put in its place.

Sat Jul 30, 2016 10:45 am

Running a later transaxle is a common swap, even if the stock 36 horse engine is retained. The gearing will be closer to stock split case transaxle if you use a 4.125 R&P gearbox. Of course, the 36 horse isn't a power house so it will feel a bit stronger with the lower gearing provided by a 4.375 R&P.

Sat Jul 30, 2016 10:58 am

Any of the Split Cases I've taken apart had a r&p ratio lower than 4.37. It's been a long time, but I think it's a 4.43. They did have a little higher 1-4 ratios though.

Addition: After taking a closer look, you are correct. The higher 1-4 ratios with the 4.43 r&p actually do make the overall ratios closer to a 4.12.

Sat Jul 30, 2016 11:45 am

The split case R&P that I have seen are 4.43 R&P but 4th is a tall 0.82 giving a final drive ratio in high of 3.63. The 4.125 with a 0.89 4th works out to 3.67 in high, about the closest stock gearing match. 1st through 3rd are also a little taller in the split case, so those ratios end up closer with the 4.125 tunnel transaxle too.

Sat Jul 30, 2016 12:00 pm

gkeeton is correct.....I measured the spider gear cross shaft retaining pin on my Zwitter transmission, and it looks to be 6mm in diameter. The pin (part number 111 517 181?) looks to be 40 mm long. One end has a slightly increased diameter by dishing of the end, and the other end is peened much more irregularly. The cross-shaft diameter looks like 16 mm. The pin bores in the differential carrier on either side of the shaft are about 10.5 mm long. So, if it is this pin, you could measure the length of the broken piece, subtract it from 40mm, and perhaps visualize the position of the remaining piece, assuming it broke off flush with the differential gear carrier.

But......what obstruction could a loose pin have hit? And how could the broken piece get to the front drain plug?

Sat Jul 30, 2016 12:36 pm

I would say from the last picture splitjunkie posted, a loose pin could have made contact with the pinion head. I've found lots of stuff in later transaxles in opposite ends from where they were located. I can't remember how big the oiling holes are in a Split Case, but if it will fit throught the hole, it could make it forward.

Sat Jul 30, 2016 8:41 pm

Thanks for all the information and suggestions. I will measure the pin next time I am out where I keep the car. It lives on the CA coast and only gets driven around town a little on the weekends. I do not think it is a roller from a bearing. It is about the right size but the surface finish is not right, and the ends are not finished as a bearing would be. From Memory, the pin is roughly 1/4" in diameter and about 5/8" long. It definitely came out of the forward drain. I do not think that the transmission has ever been rebuilt. It is also likely that if I were to rebuild/replace it, I would find one of the later trannys because I would prefer to get the syncro 1st gear and do away with the split, so I may keep driving it for now, start looking for a replacement tranny, and pull this one and put it in a corner in the event it may be worth something to somebody for parts someday. Thanks for all the information. My best guess is that it is the pin from the differential and it somehow found its way forward. Crazy thing is how the heck did it go forward and not just end up on the rear magnetic plug. There is always a chance that is is just random junk that somehow ended up in the transmission, maybe during an oil change? I found a cigarette filter in the engine sump during the first engine oil change. The guy I bought it from had three kids, if kids see a hole, why not shove something in it? The crazy thing is, this car, that sat for so long, and is all original, with some cleaning up, TLC and fresh liquids has been running great and not making metal. They really dont build em like they used to...

Sun Jul 31, 2016 4:30 am

I would NOT keep driving it. If the piece you pulled out is the locking pin, there's no real way of knowing if there is any of the pin left holding the cross shaft in place. If the cross shaft were to come out, I would imagine it would slowly work it's way out, hitting the pinion head. While this may make start making a noise that would get worse, and worse, it may also slide out quickly jamming against the pinion head locking the rear wheels up. This might happen pulling out of the driveway, or it may happen going down the road forcing the car into oncoming traffic. Regardless of if/when/how it happens, it's definitely going to destroy the transaxle. If you ever want to have the original transaxle to offer with the vehicle if you decide to sell it, pull it out now while it still may be able to be repaired.

Sun Jul 31, 2016 5:55 am

gkeeton@zbzoom.net wrote: I would NOT keep driving it. If the piece you pulled out is the locking pin, there's no real way of knowing if there is any of the pin left holding the cross shaft in place. If the cross shaft were to come out, I would imagine it would slowly work it's way out, hitting the pinion head. While this may make start making a noise that would get worse, and worse, it may also slide out quickly jamming against the pinion head locking the rear wheels up. This might happen pulling out of the driveway, or it may happen going down the road forcing the car into oncoming traffic. Regardless of if/when/how it happens, it's definitely going to destroy the transaxle. If you ever want to have the original transaxle to offer with the vehicle if you decide to sell it, pull it out now while it still may be able to be repaired.

I agree 100%. If it is part of the differential retaining pin then when the rest comes out you can expect a spectacular failure that at best will get you stuck somewhere with a destroyed transmission or at worst instant loss of power with locked rear wheels, a destroyed transmission and perhaps a destroyed car or two and serious injuries or death to you or others.

Sun Jul 31, 2016 10:14 am

It can't be from the diff. If it were, it would have had to pass through the pinion shaft's bearing to get to the other side.

Sun Jul 31, 2016 10:30 am

[quote="splitjunkie"]I don't have one opened up otherwise I would look. In the 52 -57 Bentley manual I only see two pins. One holds the Reverse sliding gear shaft and the pins mentioned on the differential.

The reverse sliding gear shaft pin is only accessible after splitting the case and removing the main shaft.

Let me assure you that pin is completely accessible if you find it in the sand after putting the trans together. you do not get to put it into reverse after that but does make a nice tingly sound when the gears are running.

Sun Jul 31, 2016 12:51 pm

OK folks, I had a look at the case halves for a Zwitter tranny and a '59 tranny. There are indeed open passageways between the ring gear chamber, and the gear cluster chamber. The passageway in the left case half is about 1" x .75", and could allow something to pass through. These cast-in passageways are smooth with rounded edges everywhere, and are definitely not machined in. Most likely they are there to speed up the flow of transmission oil between sections, when refilling.....the 2 passageways are below the fill plug in the vertical axis. These passageways do not show in the typical workshop manual vertical and horizontal cross-sections, where you can at least see the bores for bearings and selector shafts.

The case half locating pins look to be 8mm diameter, BTW.

There are a number of subtle differences between the late '52 and the '59.....interesting stuff!

Sun Jul 31, 2016 6:09 pm

Bruce wrote: It can't be from the diff. If it were, it would have had to pass through the pinion shaft's bearing to get to the other side.

Bruce, you've never found spider gear teeth on the front magnet, or 1st gear teeth on the diff magnet? When I used to constantly work on off-road abused transaxles, I had found that MANY times. If it didn't come from the diff, what other single part inside the trans uses that type of pin?

Sun Jul 31, 2016 7:09 pm

You should be able to see the differential and pin in question through the drain hole on the bottom of the diff section of the case.