1960 W111 jumps out of 4th gear

[TomHM]

Hi all,

I have a 1960 220Sb with the 4-speed on-the-tree transmission. I have just got it on the road in my ownership but it doesn't want to stay in 4th gear. It seems to go in gear fine but gently throws itself back into neutral after a few seconds. Any ideas what might be causing this and how to solve it?

I had to change the shift rod ends before I could drive it as the bushings had crumpled into nothing and one was tied together with wire. Could it be an adjustment issue here? I've also seen another suggestion online that there's a flange nut somewhere on the gearbox which can come loose and cause it to jump out of gear - though apparently this is usually combined with an erratic speedo which mine doesn't suffer from.

Many thanks in advance.

[Todd Miller]

Since you've replaced those bushings, the issue is probably due to an alignment issue, in that; the shift fork in the transmission, isn't moving the shift collar fully onto the 2 rows of teeth (1 set on the synchronizer, 1 set on the side of 4th gear), and the spring loaded collets that hold the collar in position, are remaining "spring loaded"... so they just eject the shift collar back into neutral (sitting between 3rd and 4th).

If it were mine, I'd disconnect the linkage from the trans, shift the trans into 4th by hand, rotate 1 raised rear wheel in order to confirm that the trans had dropped into, and locked into, 4th, and then adjust the linkage so that it would align with 4th position, and could be re-attached, without loading or pulling on the transmission shift lever(s), and dragging the trans out of 4th, or pushing too hard toward 4th.

These transmissions usually take automatic transmission fluid, not gear oil, and they won't shift at all if something other than ATF is used. But check what should be in yours, as a 1960. Mine is a '66.

[TomHM]

Gearboxes are a bit of a dark art to me so I appreciate your really clear explanation. It makes a lot of sense. That approach for setting the adjustment is a great idea too - I'll definitely give that a go.

Thinking about it, I also had to change the bushings that are in the arms that attach directly to the gearbox. This could also have thrown off the adjustment of the rods.

I have changed the oil with a fresh fill of ATF, as specified in a workshop manual that I have. I did this before ever taking it on the road too so I'm unsure if this made a difference. That said, there wasn't a whole lot of the old oil in there which probably didn't help anything.

[Todd Miller]

https://www.quora.com/What-are-synchronizer-hubs

^^That link will take you to a blow-up diagram that is color coded. You'll have to scroll down a little, but then you can click on the image. It shows what the transmission looks like, in the area between 2 different gears. For example, between your 3rd and 4th gear. Your gear shift movement, moves the yellow shift collar, one way, or the other, in order to "snap" up against one of the gears, shown in gray. The orange colored blocks that are shown, have springs under them, allowing the orange blocks to keep that yellow shift collar from moving side to side. The collar remains held centered, and in neutral, until you shift towards a gear. Then the collar over powers those orange blocks, as it moves to one side of them. The orange blocks then snap back up, and hold the collar pressed against the gear you've selected.

So if your linkage doesn't shove that collar over far enough, the orange blocks won't force back up and hold the collar against 4th...so the collar just gets ejected back into the neutral position.

[TomHM]

Ok, thank you. I've studied that for a good ten minutes or so now and I think I've got it.

I guess the fact that the car will stay in third without any issues suggests that the struts are working just fine. So it's logical that they're not fully engaging when the shift sleeve is pushed in the opposite direction.

[Idle]

The rod adjustment might be the problem. I know that Chevy trucks from the 60s had problems with gears wearing and this would cause them to pop out of gear while driving.

The solution was to shift into third, the gear that saw the most wear and resulted in most of the pop outs, and rest your hand on the end of the shift lever as you drove. You starred with your left hand.

The added weight of your hand on the end of the shifter was enough to keep the thing in gear. This assumes you had a three speed with the shifter on the column.

And that is your high tech solution for the day!

[Sugar Bear]

@ Todd Miller...

Is there a method that the OP could use to pin/index the linkages with a drill bit on the column and then set/adjust the shift rod length to the arm similar to a four on the floor shifter? My 114 and 123 manuals had that feature.

[Todd Miller]

Originally Posted by Sugar Bear

@ Todd Miller...

Is there a method that the OP could use to pin/index the linkages with a drill bit on the column and then set/adjust the shift rod length to the arm similar to a four on the floor shifter? My 114 and 123 manuals had that feature.

I don't know, which is why I suggested disconnecting the linkage from the transmission, then shift the trans into 4th using the shift arms on the trans, and then adjust the shift linkage rods to fit the position of the arms on the transmission.

[Idle]

Originally Posted by Todd Miller

I don't know, which is why I suggested disconnecting the linkage from the transmission, then shift the trans into 4th using the shift arms on the trans, and then adjust the shift linkage rods to fit the position of the arms on the transmission.

I did that on a 1962 Pontiac. It worked.

[Sugar Bear]

sl113.org SL Pagoda group has info about the adjustment. Search on 1961 220sb shift adjustment.

[TomHM]

Originally Posted by Idle

The rod adjustment might be the problem. I know that Chevy trucks from the 60s had problems with gears wearing and this would cause them to pop out of gear while driving.

The solution was to shift into third, the gear that saw the most wear and resulted in most of the pop outs, and rest your hand on the end of the shift lever as you drove. You starred with your left hand.

The added weight of your hand on the end of the shifter was enough to keep the thing in gear. This assumes you had a three speed with the shifter on the column.

And that is your high tech solution for the day!

That's what I've been doing to date on the Mercedes. Fourth gear is lever down so I've been resting my hand on it whilst driving.

I guess it's possible that it was like this for years before I bought it.

[TomHM]

Originally Posted by Sugar Bear

sl113.org SL Pagoda group has info about the adjustment. Search on 1961 220sb shift adjustment.

Thanks. I've found the thread.