Gear alignment T25/T3

[Vodim]

Hi,
I have a T3 from 1990, diesel, 4 gears. I have been having trouble with the gears so I changed all the bushings and other worn parts underneath such as shift lever and the lever with the plastic ball joint and also the components in the lower end of the gear stick (sorry if the terminology is a bit wrong, I am neither British or very experienced with cars). After this I did the set up with the 23 mm piece as a guide within the shift mechanism housing. There are some really good youtube videos on this and also many threads on this forum about all this. When finished I took it for a drive, the gears worked quite good and so much smoother than before. Drove 6 kilometers, stopped and turned around home. Now everything was different, all of a sudden I couldn't get third in until after much struggle. Now it acted a lot like before the repairs. Then too I could drive a while and everything worked fine until all of a sudden nothing worked (with the gears).

What I realised now however, when I got back home from the test drive, was that the neutral position had changed. After the initial setup with the 23 mm piece, neutral is in line with gear 3 and 4 but now all of a sudden it was around gear 1 and 2. I don't know why this was as everything was still tightened and in place as before. I noticed however that the lever with the plastic ball joint that is connected to a pin or a piston into the gear box cannot be "pushed in" into the gear box. And I remember that this was a bit of a trouble when I did the repairs, I could not get this arm straight in the "left-right" direction (as opposed to front-back).

So now after the drive I disconnected the front rod and back rod unscrewing the middle clamp and detaching the rods from each other to make sure it was all loose and free. And I still couldn't move the lever in and out of the gear box just pushing it by hand. With light strokes with a rubber hammer it went in and then I could pull it out again but not very easily. And it just stayed in if I tapped it in and stayed out when I pulled it out.

SO... my question is, do you think this is the problem (that the lever does not move freely in and out of the gear box)? And if so, what do I do? Is it the spring inside the gear box that needs changing?

Sorry for a long post. And thank you in advance for any advice you can give me on this.

Jonatan

[Aidan]

My guess is that the bolt for the clamp that joins the front and rear parts of the linkage has been installed incorrectly, the clamp must be fitted so the bolt is vertical and on the right side so it aligns with the cut out in the clamp, the tube, and the notch in the splined rod - in this position the bolt cannot be fitted after the rods are joined, with head on top (which appears optimal) but only nut on top as there isn't enough clearance between the clamp and the floor of the van to slip the bolt in from above: I have often seen the clamp fitted with the bolt horizontally on the top, sets up fine, then do a manoeuvre selecting reverse, and suddenly it is all out of alignment again

[Vodim]

The clamp was installed with the bolt vertically but with the bolt on the left side, bolt head down and nut up. I can turn it 180 degrees, but will that really make a difference?

You don't see any problem with the "pin" in the gear box not moving freely in and out?

[Aidan]

The clamp was installed with the bolt vertically but with the bolt on the left side, bolt head down and nut up. I can turn it 180 degrees, but will that really make a difference?

You don't see any problem with the "pin" in the gear box not moving freely in and out?

I might be wrong about which side the bolt goes, but it must align with the groove in the tube

Yes the ball should be able to move in and out of the gearbox in the neutral position (ball vertical)

if it doesn't then chances are either the relay lever for 1st and 2nd gear inside the box) has parted company with its shaft or the 3rd 4th synchrohub has broken and the box is still in gear or in a false neutral and the selector shaft cage is blocked by the 3rd 4th selector fork - with your previous symptoms the broken 3rd4th hub may be the most likely

4 speed JX, ABH code box, is fairly rare, most JX came with a 5 speed
a petrol box like ABD would give you pretty much the same 4th gearing but higher gears 1st through 3rd, you wouldn't get the same acceleration and keep the turbo spinning as you change gears as the gaps are bigger

[Vodim]

I have now taken out selector shaft to inspect the springs as it is this part that does run smoothly. Got the lid of with the spring and rubber seal and the actual shaft out. Everything looks ok though... don't know what to look for really. I thought the spring would be broken but it looks fine.

[Aidan]

have a read of the gearbox section in the Bentley manual, it all in there
Did the selector shaft come out easily ?
Is the pivot cap the top hat and spring press against intact or has the section the shaft passes through parted company with the larger outer section that sits in the case ? Top hat is the loose pressed metal part that sits on top of a circlip on the shaft, which the spring bears against in the 4 speed, so forcing the whole shaft over to the offside under spring pressure

[Vodim]

Thanks, yes I have tried to find the relevant section in the Bentley manual but about this part the only thing I find is the overview I attach here. The parts that you mention that I am guessing are what is called retainer in the image below and also the big "cup" on the shaft as well as the big spring. It looks to me like they are all intact. I attach 2 photos below on how they look.

As for the question if it was easy to get the shaft out: I couldn't get it out by hand. I had to use a rubber hammer to tap it slightly from the side where the arm with the plastic ball normally sits. I didn't have to use much force, light tappings were enough. I had to tap it all the way through until I couldn't reach it more from that side and then I could wiggle it out by hand. Just as when everything was installed, then too I had to tap i lightly to get it "into the gear box" (away from position 3,4). To get it back I think I had to tap on it while pulling it with my hand.

[Aidan]

take a look in the hole and see if the slots in the selector forks are still in line as should be the aperture in the relay lever, I suspect the 3rd 4th fork, the top one, won't be in line and thus you will struggle to get the shaft back in the box as the hammer on the shaft, the part that moves with the shaft relative to the cage and engages with the selector forks has to pass through them.

Just checking - the box hasn't been worked on recently has it ?
The currently available nylon bush that is in the side of the case under the seal on the selector ball side of the case is a bit of a tight fit and can grip the selector shaft causing the symptoms you describe as noted on the Weddle website

you can also carefully try and select 1st and 2nd gears by moving the relay lever and observing the end of its pivot shaft (the lowest hole in the case now exposed as you have the reverse switch cover off) which should also rotate, if the relay lever doesn't pivot about the axis then it has parted company with the axial pivot shaft

[Vodim]

Many thanks! I will do some translating and googling to understand all of what you wrote I will check all this and get back!

[Vodim]

The gear box hasn't been touched for at least ten years but probably longer than that. My guess is never but who knows.

Ok, so the slots (up, down and and on lever) seem to align (se picture). I also tried to move the relay lever and I could only wiggle it a couple of milimeters back and forth. And it seemed like the pivot shaft then was moving then as well (see video).

[Aidan]

nice work and pics and video
you should be able to move the relay lever more than you are doing in the video, maybe not easily whilst videoing, but you should be able to move it enough to engage either 1st or 2nd gear; but I note when you are moving it a little, the axial pin is moving side to side a little in the bore in the case, which is a bit more than averagely worn, but it is not rotating, it should rotate with the rest of the relay lever, by something like 15'-20' in each direction
Take a look at the top of the relay lever there is a slot in it which the bolt on top of the gearbox (which has a pointed end) should be in the slot, and when in middle neutral position it should be in the middle of the slot, if you can move the relay lever sideways but it isn't rotating about the axial pin then likely they have parted company, which would account for the difficulty pushing the selector shaft in and out, the relay lever is the obstacle pressing on the cage of the selector shaft adding friction

the selector fork nearest the hole is the reverse selector fork that will only move rearwards, the relay lever operates the 1st 2nd fork and the fork furthest from the hole is 3rd 4th, which I had expected to be out of alignment if the synchroniser hub was broken and the slider not moving freely - it too will go in both directions, backwards is 3rd, forwards is 4th

the relay lever reverses the direction of the selector fork, rotated forward it pushes the fork backwards to engage 1st gear, and vice versa

you can see the selector shaft passes over the input shaft or the gearbox, what I call the mainshaft, what others might call the first motion shaft - the cut teeth you see are 2nd gear fixed gear, the ones to the right are 1st gear fixed gear

Is there any wear on the bottom of the selector shaft suggesting that it has been rubbing on the input shaft ?

[Vodim]

Again, many thanks!

As for the bolt on the top I think it is in the middle of the slot. To me it looks like there is the same amount of space behind and front of it. I tried to take a photo of it but it is taken with a little bit of an angle so it might not look like it is in the middle.. but I really think it is.

Now I managed to move the relay lever properly into gear 1 and 2. You can see in the video that the pin is rotating as well. Good news I guess? I also managed to push it forward into gear 2 even though I can't in the video. Tight already without filming

As for potential wear on the selector shaft, there is no wear underneath, see video. It is in the front though but this could be from anything in the past. Unless it touches the teeth? But it looks like marks from an angle grinder or something.

All in all I don't know what to make of this. Any advice on the next step?
https://youtube.com/shorts/wAeIKeABy0g?feature=share

[Aidan]

okay, that's great, looks okay, maybe the rivetted join of the the two parts isn't perfect but it looks like the plate and shaft of the relay lever are still together.
I'd just check the big cup slides okay in the hole if you can, but it came out okay and isn't broken and doesn't look damaged and there not great globs of silicon in there, not sure there's enough room though to do it with box in van and shaft wrong way around.
Then check everything is in line and put the selector shaft back in (slot in cage faces backwards and aligns with the fixed steel pin in the case (which you might want to check is undamaged and firmly held in the case) and put the top hat and the spring and cover back in and see how it slides.


I'd probably drop the oil and see what if anything the magnetic drain plug has to tell us, but the box is very clean inside so it looks like it has been oil changed (well maintained) - if oil is clean can be reused. Check the filler plug undoes before dropping oil.

The marks on the shaft that look like angle grinder marks are from contact with the mainshaft, mostly the back of 2nd fixed gear, just a sign the main shaft is moving back and forwards as the main shaft bearing displaces in the case (and may be worn) due in part to the helical cut of the gears and the bearing being a ball bearing and wear to the reverse idler stop plate and end case stop that limits the movement of the bearing - a slightly flawed design

Before you assemble it you might try and lift the mainshaft whilst you are checking the pin it shouldn't move much vertically, if it does then it could be one of the bearings supporting the shaft is damaged, but the drainplug magnet will likely provide evidence of that too.

[Vodim]

Working on it now. The fixed pin seems fine and the main shaft doesn't seem to move up vertically. Although when I tried to force it upwards it jumped forward (towards the front of the car) a couple of millimeters. So that shaft is definitely moving back and forward as you mentioned. I just got the selector shaft back in now.. it is very tight and once in I can't move it an inch by hand. As tight as it is now I can't see it sliding as it should even with the spring pushing on it. As it has been laying on the work bench for a couple of days now it is a bit dry. Can I take it out and put some oil from a regular oil can on it? Or is it bad that that oil gets mixed up with the gearbox oil? I don't have any gearbox oil at home unfortunately.

[Vodim]

Don't know if these videos tell you much but might give an idea about the fit

https://youtu.be/7WcJCJqzh6A
https://youtu.be/xmWl0i5w7Vg