A833 gearbox 4th gear doesn't work

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l6hmus

l6hmus

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Hi,

My 4th gear is missing and 3rd gear doesn't come out.

First time this happened we opened the gearbox and saw that 3rd and 4th syncro ring pin's have popped out of their place and that's why the 3rd gear is stucked.

We put the pins back to their place and it worked for about 6 km (first few KM I ever drove my car with this gearbox).

Now we opened it again (first time I did it my self and didn't know what to look for).

We have two questions why is this thing happening (the pins pop out)
here is a picture:

https://dl.dropboxusercontent.com/u/19022509/pins.jpg

Second question is that is this normal:

https://dl.dropboxusercontent.com/u/19022509/teeth1.jpg
https://dl.dropboxusercontent.com/u/19022509/teeth2.jpg

it seems that some of the teeth have been cut out (half) ?

problematic parts have marked red.

In my country we don't have a shop/garage who knows this gearbox, so we need to figure this out ourselves.

Any ideas ?
 
The only time I have ever seen the detents (pins) pop out so far they locked the slider ring was because the slider ring traveled too deep into the gear teeth and allowed it.
I have also seen the detents (pins) have the exposed end pop up and out of their slot and do the same thing.

Obviously someone modified that trans, and the only reason I can think of that the interlock teeth would be cut out like that is they thought for some reason it would shift easier (I don't see how it would because of that though)

You may find other areas where this thing was cut or ground on in the shift linkage or forks.

Looks like someone was experimenting to me.
 
the 3 things that are coming out of position are called struts, there are 2 strut springs with a tang that go inside the back of the struts. something is not assembled correct or worn. a shifter with stops adjusted correct may help. the remove of every other tooth is called slick shift race modification by chrysler, done to speed shifting, did not involve grinding on shift linkage or forks
 
Does this "slick shift race modification" mean that this gearbox isn't streetable (read from some forum that you have to double clutch to shift down)?

If so what to check/replace to make this gearbox drivable ?
 
That is what we called a crash box. I use to run a Ford Top loader 4 speed (because it had a 2.78 first gear) in my 69 Camero bracket car. This helped eliminate missed shifts. But the problem is it is a race piece only. When not racing you had to push the clutch in and snatch the shifter into the next gear. Second and third is probably done the same way?
 
No hold on boys.
I have modded my box the same way, and its dynomite on my streeter.Notice the brass synchronizer rings are still in there. And the hubs are not modded. So its only half crash-boxed. As long as the brass is good it will be fine for street. You wont notice any difference, except it shifts like butter at 7200.
Now, I see one problem, the brass rings are sitting very low on the cones.So if the shifter over-shifts it will scoot those brass out to the end and the backside will pop out.
Question is why is it overshifting? Ima gonna guess it an early side-cover with the brass forks, and the interlock pin is missing or too short.The following test does not apply to the late-style roostercomb interlock cover.
Heres the test ; 1) lay the cover down on the bench, 2) shift the rear, 1-2 lever into a gear, 3) attempt to shift the front, 3-4 lever into a gear. There should be almost zero lever movement available.Maybe 1 degree.
If you have more, say 4 or 5 degrees, take the thing apart and either replace the interlock pin or weld it up to work.I suppose its also possible that somebody replaced one or both of the ball-bearings with smaller ones.They should be the maximum size that fits in the tube.

Oops, almost forgot. Before you do anything, check the back bearing for endplay.There should be zero. The test is to pry the geartrain back and forth. The output shaft should not move longitudinally. Its possible the bearing is worn out or the wrong bearing was installed in there. That bearing is special, so check it carefully.
 
AJ/FormS said:
Now, I see one problem, the brass rings are sitting very low on the cones.So if the shifter over-shifts it will scoot those brass out to the end and the backside will pop out.
Click to expand...

The overshifting was my original thought, but after looking closer at the ring wear I have to wonder. (didn't the syncro rings have a notch in them that those slide ring detents fit in?
And wasn't that problem caused by the syncro rings wearing and getting too far away and allowing the ring detents to move out too far like in the pictures?)
Been so long I can't remember for sure.
I'd like to see that thing on the bench in person. :)

Oops, duh.
That's what you said. :D
 
Sorry for not replying but it turned out quit good.

The mechanic took the trans apart and inspected everything, put the trans back together and said that he didn't find anything wrong.
I adjust the shifter stoppers (they were very loos). Now I have drven the car for 200 KM and no problems.
So it seems that the reason was overshifting.

Kristjan.
 
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