Gearbox problems

[valimar]

Hi All,
After driving for a few years with minor problems with my gearbox I think now is time for a complete overhauling! A couple of days ago after driving hard (190km) for about one hour, the gearlever got stuck in 5th gear! I had to stop the engine a few times, to be able to change gears, and with some difficulties I could reach home. Putting the car in the garage backwards I had also problems: it was just like the wheels were blocking causing some resistance, not willing to go backwards. I suspect some synchromesh must be jammed. With the wheels was nothing wrong, so I took the gearbox selector out and checked the cables (AB) and oil level, but everything was fine! I know that taking the gearbox out is one hell of a job, but I don’t see any alternative. My question is: in case I bring the gearbox for overhauling (to a reputable specialist) has Lotus still parts available to do the job, or is it wise to try to find out a used gearbox? The problem is with used stuff you never know in what condition it is and here in Portugal there is not much choice in used parts! Any clues would be appreciated.
Cheers, Rodrigo.

[Dave Eds]

Rodrigo

click on my link below and you will see many gear parts listed.

[Specky]

Hi there,

IMHO the problem you have is quite common...

Several people in the past year have had a 5th gear Phaff...

It would seem the gearboxes are OK for plodding around, but once you give them the beans for a while they tend to break..

There are a few reason why you can't get out of 5th...

1) There's a cam in the selector that prevents a reverse selection straight out of 5th, this sometimes slips not allowing the gearbox selector out of 5th

2) Allegedly when you remove the gearbox end cap there's a nut in there that comes loose this allows the 5th drive shaft to slip..(This can be accessed with out removing the gearbox) I've asked on another thread for a picture on which nut this is, and a better description as I have the same problem as you..

3) An internal fault in the gearbox

Overall I'm going to have a look in the end cap at the beginning of April, I'm also waiting to see if RIP can shed some light on the matter after he's had his visit to GST. Failing that I have another gearbox to go in, driving around with only 5 gears is getting a bit annoying...

The thing to be careful is not to snap your gear change cables, I've managed to snap two now...

TTFN

[rip]

Sounds very like mine. I need to select reverse before 1st. When I engage the clutch this happens with a lurch forward as something internal appears to move. I can then find my way through the gears up to 5th (but it is a little crunchy).

After removing the (RHD) near side wheel, I could remove the gearbox end cover:



You can see the 2 geartrains. I believe the gear wheel on the right is 5th. Apart from the gears moving against each other, engaging 5th is the only time you see movement from this end.
The nuts Specky is talking about are the big ones (32mm I believe) on the end of each geartrain. The service manual gives a torque of 127NM for the 5th gear one, but I found no mention for the front one. It is the same size & for the same purpose, so I assumed it would need the same torque.
The nut on 5th gear was tight, but the other one was REALLY loose & took several complete turns to tighten.

Made no difference though. I am dropping the car off at GST's on Saturday to have this looked at.

[valimar]

Sounds very like mine. I need to select reverse before 1st. When I engage the clutch this happens with a lurch forward as something internal appears to move. I can then find my way through the gears up to 5th (but it is a little crunchy).

After removing the (RHD) near side wheel, I could remove the gearbox end cover:



You can see the 2 geartrains. I believe the gear wheel on the right is 5th. Apart from the gears moving against each other, engaging 5th is the only time you see movement from this end.
The nuts Specky is talking about are the big ones (32mm I believe) on the end of each geartrain. The service manual gives a torque of 127NM for the 5th gear one, but I found no mention for the front one. It is the same size & for the same purpose, so I assumed it would need the same torque.
The nut on 5th gear was tight, but the other one was REALLY loose & took several complete turns to tighten.

Made no difference though. I am dropping the car off at GST's on Saturday to have this looked at.

Exactly, that lurch forward, as you call it, was just what i had for quite a while! About the nuts you and specky mention if I understood correctly tighten it didn't solve the problem? Or do you want to check it by a specialist? If tighten the nuts would solve the problem would be a blessing 'cause i'm not very glad if I have to take the gearbox out! Please explain me why tighten the nuts didn't solve the problem.
Cheers

[Specky]

I wonder if you've found the cause Rip,

Long story short...

The forward nut came loose...and eventually you trashed the gearbox as the shaft slid out...

I guess several superstitions could be made...

1) You might lose the torque on one or both nuts
2) Our symptoms are very very slightly different. (Not clunky)
3) Owners it could well be worth Torque checking on your own car at the earliest opportunity
4) Make it part of your servicing schedule when you change the gearbox oil..

I'm going to go out on a limb and say mine will be loose on the rear, because the symptom is slightly different

TTFN

[rip]

Good point about the nut coming loose, Specky. The shafts mesh with each other, so that makes me wonder if one is more at risk from this than the other?

[Monty]

I wouldn`t mind checking my Nutz

The question is do i need to drain the gearbox oil before removing the end cover?

[Specky]

I wouldn`t mind checking my Nutz

Now you're Torque-ing....

I know a certain lady who could tighten your nutz if that'd be any help...

When I took the cover off my other gearbox about half a cupful came out, but I don't know how much was in there to start with...

TTFN

[Monty]

Now you're Torque-ing....

I know a certain lady who could tighten your nutz if that'd be any help...

Won`t you need your own wife for tightning your Nutz up 1st

[rip]

When I took the cover off my other gearbox about half a cupful came out, but I don't know how much was in there to start with...

TTFN

Sounds like yours was properly filled then.

[valimar]

Hi All,
I just open the side cover of the gearbox and just like by Rip the left 32mm nut was loose! As you can see on the pictures it was already damaging the 3 nuts on the inside of the cover. I took the oil out (MTL Red Line) and it looked very clean without any metal particles. Now I'm going to fasten the nut (127nm?) and seal the cover with liquid gasket because the OEM one is damage! Then i cross my fingers and hope everything works fine!!!

[rip]

My gasket tore too. I took the end cover off at my parents' & dad had a sheet of gasket material from which he cut me a replacement.
Good luck with yours. I hope the tightening sorts it.
Mine is off to get some attention from a proper Lotus mechanic on Saturday. I will hopefully know by the end of next week what the solution was.

[valimar]

Rip
I looked today and the service manual gives, in fact, the torque for both big nuts: Just take a look in the Service Notes section FF page 23! 127Nm for both as you mentioned.

[rip]

Mine's at GST now.
Gerald told me that he remembers this being a more common fault when the cars were newer.
The '5th gear bolt' works it way loose & allows the gears & synchro rings on that shaft to slip along the slightly, so they no longer align with those on the other shaft. Simply tightening up this bolt will not move them back again so he suspects my gears are all out of line.
The bit you can see moving on the rear shaft when engaging 5th, is 5th synchro, not 5th gear.
As I posted earlier, I suspect the direction of rotation encourages this one to loosen & the other to tighten.
He seemed to be quite optimistic about being able to reseat these without having to remove the gearbox & that (hopefully) there will be no further damage.
I suspect that to do it without removing the gearbox will take a little more experience than most of us have.

I'll find out later in the week when Gerald has had a good look.

[rip]

I got good news from Gerald today.
The gears on the front geartrain had indeed slipped along the shaft when the bolt became loose.
After removing 5th gear, he was able put these all back into place without having to remove the gearbox. 5th had suffered minor damage, but not enough to prevent its re-use. He advised me that there is a possibility 5th may not engage as smoothly as before, but it will probably feel no different.
He also expected that a Lotus dealer would almost certainly have replaced the entire gearbox.

The only negative is that I cannot get to Newmarket until Saturday to pick it up.

[valimar]

I sincerely hoop the news are really good... yesterday i fill up the gearbox with new oil and went for a ride. shifting was more or less good till i shift into 5th, then the gearlever block! I had to stop the engine to be able to get to the garage! So, as long as I don't use the 5th speed I can shift! I think my gearbox has to come out anyway.
I didn't know it was possible to remove the 5th speed shafts with the gearbox "in loco"! It gives some new perspectives!
Has anyone experience with this please let me know! Rip, i hoop in your case the problem is minor!

[rip]

Sounds like yours is suffering the same as mine, only not quite so bad.
I would expect it needs someone with a bit of experience to align the gears with the shaft in situ. I'm glad I took it in ASAP. Good luck with finding a Lotus mechanic who is not a dealer.

[RayD]

Out of interest Rip, could you try to find out what’s stopping the various parts sliding back into position when the nut is re-tightened?

Thanks Ray

[rip]

Out of interest Rip, could you try to find out what’s stopping the various parts sliding back into position when the nut is re-tightened?

Thanks Ray

I'll have a chat with Gerald when I pick up the car on Saturday.