Gearbox mounting

[Tyrone]

How can I tell if it is goosed? After hitting a bridge recently I thought I had escaped lightly but it is now apparent that one of my engine mount rubbers is goosed and the gearbox mount might be.

 

I jacked the car up, then put the jack under the gearbox at the junction of the casing and the extension casing. I could see the bracket with two bolts and a circular hole. Gently raising the jack the gearbox lifted and the car didn't. What, I'm guessing, was part of the mounting rubber pulled away from the circular hole in the bracket. The Tony Weale book doesn't help. Has the mounting failed and can it be replaced with the gearbox in situ.

[The Pikey]

The gearbox mount is about as flexible as a piece of oak so I would say it is well and truly knackered.

 

Jason

[Tyrone]

But how has it failed? Diagrams I've seen seem to suggest the gearbox is bolted by a central bolt through the mount to the bracket, but there is no central bolt on mine or a hole for a missing bolt to fit in to.

[The Pikey]

From memory with it all in place you will only see the two bolts that attach the mount to the chassis plate. The bolt that fixes the mount to the gearbox is hidden by the chassis plate. Sounds like the bolt has snapped or come undone.

 

What gearbox have you got?

 

Jason

 

Edited by - Jason Fletcher on 22 Jun 2011 00:43:57

[DJ.]

Jason is right, you won't see the central bolt, because the plate is in the way.

I haven't tried it, but I think it should be possible to replace the mount if you have space to move the engine and gearbox far enough forward to get access to the hidden bolt.

 

Weird things happen after an accident like that. I had a heavy shunt in a Lotus Elan, and had a lot of backlash in the diff after it was repaired. In the end I think what happened was the weight of the propshaft flying forward when the car stopped was enough to crush the adjustment washer on the pinion shaft in the diff!

 

I hope you get it sorted without having to take the engine out.

 

Duncan

[Tyrone]

I have a type 9 gearbox. The chassis plate has a hole in the centre, but this is 'filled' with a circular moulding on the base of the mounting (this is my guess and the best way I can describe it). When I jack the box up the circular moulding lifts away from the chassis plate.

[Tyrone]

I've just done a search in Google and the Locost Builders site refers to a 'funny bell shaped washer' that sits under the bolt which holds the mount on to the gearbox. I'm guessing this is what I can see through the hole in the chassis plate.

 

So, the mount bolts to the box through a centre hole then the mount bolts to the chassis plate through the two side holes? If I can see the mount and the box lift upwards, what has failed? The two side bolts?

 

Edited by - Tyrone on 22 Jun 2011 09:10:34

[Paul Deslandes]

Mount

Not sure if this helps but you can see that the gearbox sits in a tapered channel and is bolted to it from underneath. The mount base plate is then bolted to the chassis plate by a bolt either side. On my '95 chassis there is a large hole through the plate so that you can undo the central bolt to detach the mount from the box. I suspect that either one side or other of the rubber has become detached from the tapered channel or base plate or the bolt has broken.

 

Edited by - Paul Deslandes on 22 Jun 2011 09:45:53

[Tyrone]

Thanks for that Paul. It's not being able to see the central bolt that puzzles me. Anyway, I've ordered a new mount and central bolt from Redline along with two new engine mount rubbers. I do love their relaxed attitude to pricing! "Can't remember how much the gearbox mount is, it's about the same as the engine mount". Bless them, still half the price of Caterham.

[lavena]

From underneath I can see the head of the central bolt holding the mount to the gearbox.

 

The mount is held to the plate (which has a hole in the centre that I can look through) by two bolts either side. The mount is then held to the gearbox by the central bolt.

 

When you lift the gearbox is the mount lifting with it? If not then the central bolt is no longer holding (or missing) if yes then the mount has probably come away from the two bolts either side.

 

Andy

[Tyrone]

It looked as though the mount was lifting with the 'box. Until I take it apart I'm not sure what has failed.

 

Can anyone confirm how much I can jack the 'box up without causing any problems?

[Paul Deslandes]

if you put a jack under the main gearbox with a block of wood to spread the load a bit, you should be able to jack it up enough to get the mount out, so long as you can get to the centre bolt. Once all three bolts are out, the mount should come out sideways. When jacking make sure that you're not forcing the top of the gearbox and/or bellhousing up against anything important like cables, fuel lines etc.

 

By the sound of it yours will come out in two pieces.

[2slo]

Sorry to hear that Brian. Sounds like your 7 won't make the meeting on the 29th either... ☹️

[Tyrone]

It would, I've replaced the goosed engine mount and the drive up the A1 isn't really stressy. Unfortunately, I won't be at The Mouse because I have a tender bid going in on Friday and midnight oil will be burning all week! It's my birthday that day too! *mad*