Jumping out of second gear on overrun

[paulnb57]

I drove a Series 3 88 diesel that is for sale and it jumps out of 2nd gear if you lift off the throttle. Is it a drama to fix?

Thanks

Paul

[Jon White]

Basically gearbox rebuild. Will probably need a new 1st/2nd synchro and probably a 2nd speed gear too.

Its never just the detent springs as people tell it is! You might get lucky and find somethings loose or similar but either way the box needs to come out and stipping.

They're easy enough to fix yourself though!

Jon

[tuko]

If the first/second syncro is on it's way out, then it's a given that the others are on their way out to.

Like Jon wrote, a gearbox rebuild is required. Doing it all at once saves you from having to pull the gearbox and fixing it again.

Todd.

[DaveSIIA]

There's a good chance the bush that 2nd and 3rd gears ride on will be worn/broken and the circlip on the mainshaft (inside 3rd gear) broken. I've rebuilt over a dozen SIIA/III boxes with similar symptoms and found these, plus 3rd/4th syncro detent springs, were the common failures. What starts out as a simple fix becomes a gearbox rebuild.

Bad news out of the way, the good news is that Series gearboxes are simple to rebuild and set up. Parts are available from the regular suppliers and the job takes a couple of hours once the box is on the bench. Attention to detail with endfloats and clearances pays dividends when you come to drive the box. All the information is in the factory manuals which can be found on various download sites.

So long as the layshaft or gears aren't damaged, the cost isn't too bad as there are a few bearings, bushes and seals. Syncro rings/hubs are probably the most expensive parts. The box has to come out anyway, so it is worth a look inside to decide whether to do the job yourself or buy a recon exchange unit.

[secondjeremy]

I've pulled a couple of Series 3 gearboxes apart recently and found on both the inner part of the 1st/2nd synchro hub had broken off in 2 places adjacent to the sluts the spring/ball/plates fit in.

I'd drain the oil (unless its been done recently) and see what comes out.

I can't see that a problem with the 1st/2nd synchro would have any effect on the 3rd/4th one which is an entirely different component.

Its possible that the nut at the back end of the mainshaft is loose and allowing everything to move (most I take off are!)

I agree that the detent springs are not likely to be the cause of the problem.

Its not difficult to rebuild the things yourself but be careful with budget parts. There's no point in buying parts until you know what's worn (most of the bearings will probably be OK) but the parts can add up.

[DaveSIIA]

I can't see that a problem with the 1st/2nd synchro would have any effect on the 3rd/4th one which is an entirely different component.

2nd & 3rd gears sit on a bronze bush that used to be a one piece assembly, now a two piece. When this wears or breaks then 2nd gear has a tendency to jump out on over run. The problem isn't with the 1st/2nd syncro but with 2nd gear moving along the mainshaft.

[tuko]

2nd & 3rd gears sit on a bronze bush that used to be a one piece assembly, now a two piece.

The one piece is far superior to the 2 piece assembly. The two moving parts tend to mushroom together at the point of contact thus giving free play on the mainshaft. When I rebuilt my transmission, I had an used but in good condition 1 piece sleeve still kicking about, so I installed it instead. To bad that they are NLA at the regular mail order suppliers, but I think that they can still be found at Dunfolds for a small fortune.

Todd.

[tuko]

Correction,

I just searched at Craddock's and they have it in stock;

Part Number : 571218

BRONZE DISTANCE PIECE MAINSHAFT 1954-81

£12.93

Maybe it could be bought on ebay ??

Todd.

[Les Henson]

Drain the gearbox and see what comes out. This quite often gives you a clue as to what has failed inside it.

Les.

[Cheesy]

I know it doesn’t really help you much but I has an early SII diesel that did exactly the same thing, the engine went terminal before the gearbox and was replaced with a petrol 4.1L straight 6….. stopped popping out, guess it must have just been the smoother motor

[jonathan day]

before you start taking gearboxes out, try tightening up the special round castlated nut on the back of the main shaft, under the rectangular cover, also seen through PTO hole, this can sometimes help this problem, good luck

[stjohn]

Basically gearbox rebuild. Will probably need a new 1st/2nd synchro and probably a 2nd speed gear too.

Its never just the detent springs as people tell it is! You might get lucky and find somethings loose or similar but either way the box needs to come out and stipping.

They're easy enough to fix yourself though!

Jon

Hi John was wondering if you had any ideas on this ?

I am fighting with this ser 3 suffix D gbox . It still jumps out of 1,2nd gear on over run and always jumps out of R g. After 2 rebuilds within a month or each other

I rebuild it , everything new everything, synkro, bush (ONE PIECE), circlips ,bearings , seals ,new reverse gear ,new springs , fork seals ,spacers to take up float.

I checked fork position but could not find the exact measurement anywhere online or in manuals (some say there is one some say you just put it in stock position ).So played around moving it back and forward , no luck , put it back to stock pos . Then checked the castle nut again , took of overdrive , checked the main shaft for movement .There was a lot , and the nut was not going to get any tighter . On 1st rebuild

So decided to take box out again and check end float and ware on casing . But then i decided NO . let me take this back to the experts as this has been going on now for 6 months . The place I took it to was a Land rover shop , that is where i bought all my parts and they have been in the Landy business sins 1972.

I had payed them the 1st time I rebuild the box , to assemble the main box for me , I could not figure out how to get the lay shaft back in , so they assembled the box . ( my 1st box rebuild )

Well I took it back to them , they are good guys , they decided to take the whole box apart Transfer and all . Go threw it peace by peace check everything again .

We then found a lot of problems , I was standing next to the mechanic while he worked on the box for 7 hrs. There was lots of end float, circlips ,one was broken , and the R gear circlip had jumped off , they put in thicker spacers front and back main shaft and , new bush just to be safe as the shaft had been mover back and forth so better safe than sorry they said and tightend up 3 and 4th as well , checked the transfer box as well all good there .

The did also find a problem where the main bearing gos through the casing on main shaft towards the front , there was ware there , So they put a collar on the front side and scored the bearing a bit ,to give it some bite and then loctite ,there was about 2 m movement there back and forth and then a new circlip .

They gave me a credit on the money I paid the 1st time, they put the box together , but 4.000 rand ( im in south africa ) later , I got home put it all back together again ,and same problem , jumps out of Revers G , and will not stay in 1 /2 gear on over run ????????????? ...

This was my 13th time pulling this box out and still not fixed . Sorry for the long story , but what the #$%%^ .. Any thoughts on what the hell is going on here I am really lost not sure what to do , I have just put 40.000.00 into totaly frame up restoring it . solar panels fridge and on and on , but can't go anywhere without Reverse gear working prop. I can't even hold it in reverse it pushes my hand back as it jumps out gear ..

I did look at box mounts and engine mounts , look fine

Thanks for any thoughts other than what I have allready done here ....

I am true lost here and so is the land rover workshop ?

[Gazzar]

Initial thoughts would be it could be you have a mix different suffix parts in there.

There are a few changes between the ABC & D boxes, have a look at the gearbox rebuild thread toward the end. One of them is the number of teeth change on one of the cogs.

If you have an "A" 1/2 and a "D" reverse you might have these problems, also if you have "C" syncro and "A" 1/2 you will have problems as the "C" on are ECM: they have coffin shaped syncro fingers - If I recall correctly, that is, could be the other way around, I'm talking from memory - which is never wise in my case.

You have a D box, check the green bible for chapter and verse, and then the parts manual for part numbers.

G.

[Jon White]

Jumping out of 1st/2nd if you've replaced the synchro mechanism already then have a look at the first/second speed gears. The teeth that the synchros lock into tend to wear also and will casue this. If youve had the replace the synchro already then the chances are that these gears are also worn.

Jumping out of reverse could be a number of things. Have you checked that the reverse gear stop bolt is correctly adjusted as it may be wrong and hence not allowing the detents to lock in. Failing that it could be either a bent or worn selector fork, or the fork being loose on the selector shaft (ive had this last one).

Firstly I assume you've checked that the castelated nut on the back of the mainshaft is tight and that there is no endfloat in the mainshaft?

Cheers

Jon

[discomikey]

The reverse gear on some models, can wear quite badly in the "fork recieving" bit and also the shaft the idler sits on can be badly worn. my box pops out of 2nd on overrun, i know its the synchro, as i had the box apart to replace the layshaft, and in a massive rush refitted the old synchro again.... leaving the new one on the bench. (only realising after test drive) i havent had time to take it apart again since.

what i might do is rebuild another box that i have and ensure its all perfect, and then fit it when ready.

being as my engines just gone poof (possibly the head, but knowing my luck its the bottom end its running on all 4 but making a very bad chuff/knock/tick noise which doesent sound like its coming from the head and shakes like its running on one cylinder ) ... ill probably pull them both out,

i have wanted to do a "front end rebuild" anyway for a while.

[JosephGozo]

Hello to all i am new to this site.

I am also a bit at a loss after a suffix D rebuilt. (6 years ago i did a suffix A series three and had no problem - just replaced bearings)

i have same problem of reverse coming off wildly and also difficulty engaging 1st and 4th gears.

i have come across this page on this forum (StJohn this might help? )

http://forums.lr4x4.com/index.php?showtopic=75814

my problem is how do i determine layshaft endfloat?

upon stripping it down again i noticed that the first gear bush endfloat is too much also in the haste i installed the first gear thrust washer the other way round. i am waiting for parts to see what happens.

joseph (Malta)

[abeljt]

Guys, a bit late.... but anyone got the solution to this problem????

[Berridale]

Hi Guys,

Pops out of 1st and 2nd.

what i notice is that on my Landy the gear lever doesn't travel far enough to lock it in either gear/

3rd and 4th go all the way in.

So what is limiting the travel of the selector?

[Peaklander]

I had the same problem on my 88” in reverse. The cause was the selector was worn around the arc where it engages with the selector ring ( is that the correct term?). This made it thinner so it didn’t push the ring as far as needed to engage the gear correctly. 

[secondjeremy]

So Beridale - what type of gearbox do you have - why do I ask? S2/2a non - synchro box is very different in respect of 1st and 2nd to a S3 all-synchro box.

Knowing the suffix letter would also be helpful.  Problem is that for S3 boxes the number for the main box is stamped on the front of the transfer case - so sometimes when dismantling a S3 box the forst challenge is to work out which one it is.

 

[Snagger]

Jumping out of reverse is most likely due to the idler shaft (the idler being the extra gear that reverses the direction of the rotation, and in this case is slid back and forth by the selector fork) wearing.  The shaft is presses into the casing and is always sat in the same position - it is fixed.  The idler gear rotates on the stationary shaft.  This eventually wears one side of the shaft, and it usually wears as a taper, so the tangential forces on the gear become thrust forces that push the gear along the shaft back to the neutral position.

Finding a company that does good work on reconditioning in Europe is difficult.  Finding one in Africa?  You’re on your own.  You’ll always get better results doing it yourself as workshops invariably cut corners and costs bumpy reusing parts that should be scrapped and not taking the time to correctly set end float, to use seating compounds on those parts which need it and generally take care in the job.

[Peaklander]

The thread was resurrected with a 1st/2nd fear jumping problem. It was me who introduced reverse and my cause wasn’t the idler but a worn selector fork, as I said. I just offered it as a possible cause. 😀

[Gazzar]

On 6/23/2020 at 9:20 AM, Berridale said:

Hi Guys,

Pops out of 1st and 2nd.

what i notice is that on my Landy the gear lever doesn't travel far enough to lock it in either gear/

3rd and 4th go all the way in.

So what is limiting the travel of the selector?

Is the main shaft nut tight? Accessable from the transfer box.

The selector fork must be in the groove in the bit that slides on the shaft ( Gear synchro). it can be in the wrong place.

The ball bearings and squares in the synchro can wear.

Finally, are the selector shafts on the outside of the box correct? A tweak of these, following the wsm, can help.