Keeping gearbox under control!

[gouldsborough7]

I think I raised this item when I first bought my Berli, but never really resolved the problem totally. Either the roads are getting more bumpy (yes, without doubt) or my gearbox is getting more mobile on its mountings (could be).

Very early on I replaced the engine & gearbox mountings with bog standard Ford fittings. With help from my local village garage's hoist, I established that the back of the gearbox was knocking on either the transmission tunnel or the handbrake mechanism. Fiddling around with shims caused alarming results, with (at worst) the propshaft trying to drill a hole through into the car interior (sounded like it anyway!).

I did manage to reach a compromise, where only really bad potholes produced knocking underneath. Rather than experiment with stiffer proprietary mountings at great expense (and no guarantee of success), I am wondering whether I could fabricate some additional mounting brackets, to bolt some rubber mounts between rear of gearbox and the underneath of body somewhere.

Has anyone got any ideas on this, please?
Cheers
Mike

[ozebrowns]

Re: Keeping gearbox under control!

Mike, I had this problem when I did my build. I hadn't realised just how much things move around under a car ! I may have been lucky but the shaft didn't actually hit the tunnel, just some fixing bolts which I was able to shorten. Also I had to trim back the hand-brake mechanism quite a bit. I didn't look into restraining the gearbox since these mods solved the problem.
Stu.

[gouldsborough7]

Re: Keeping gearbox under control!

Hi Stu
I've not had a reply to messages as far away as Oz before, so thanks for your interest. Realistically, the transmission tunnel design is too small for all of the kit that has to be squeezed along it. Then, on top of that the propshaft has to move up & down as well as rotating.

If we had smoother roads in th UK, the problem would not arise. However, I live in a rural area, where lanes are surfaced with cheap quality surfacing (I believe you call Roading), and potholes appear overnight! Hitting some of these causes a machine-gun noise underneath, which I am sure is the narrow end of the gearbox where the prop joins.
Originally, I thought it might be the back axle, but the banging occurs twice when going over sleeping policeman (traffic calming measure not human-being), so it is not symptomatic of one axle.

I was thinking to bolt some angle-iron or similar tough stuff across the bottom of the car, attach some home-made brackets to the gearbox, with engine-mounting rubbers bolted between. Easier said than done. Not so bad if I could use my local garage's hoist, and get the car 6 feet in the air. I have trolley-jacks, axle-stands and ramps, which don't offer the same opportunities of access.

Cheers
Mike

[Dane_Rescueman]

Re: Keeping gearbox under control!

Hi, I replaced my rocket box with a type 9 recently. It is a tight squeeze. On my installation (2.1 pinto) the smallest gap is at the front of the gearbox top cover! I have less than 3mm between this and the tunnel cover. This is despite moving engine and gearbox 10mm forward during the last rebuild. I have reasonable clearance between the propshaft and handbrake linkage but had to add 5mm spacers to the gearbox mount to allow access to the speedo drive. I live along a disrepaired country lane and occasionally the gearbox does contact the tunnel cover during excursions across the almost mandatory pot holes. It is only a gentle tap so I'm putting up wth it for now.

[gouldsborough7]

Re: Keeping gearbox under control!

Dane,
When I had my Berli 6ft in the air on a hoist, the garage proprietor couldn't believe the lack of space between heavy lumps of machinery and the bodywork. I had given him the job of fitting a new gearbox mount, as I was finding it impossible with the car only 1ft up and grovelling around on a trolley. He experimented with shims, and what I have at present is his best effort. Still bangs when hitting potholes or sleeping policeman bumps, but not too bad.

I must get under the car to assess the possibility of bolting some extra rubber mountings, or even little hydraulic dampers that for example very early Minis had to stop the engine assembly moving backwards and forwards. My problem I guess will be trying to attach something to the gearbox. Perhaps I might be able to bolt some heavy duty rubber lumps to the bodywork, i.e like half an engine mounting. I feed back any ideas I come up with to this message site.
Cheers
Mike

[h_m_cumming]

Re: Keeping gearbox under control!

Although my experience is with Roadsters, are you guys using the origional manufacturers engine mounts. If so they were designed to allow a lot of movement to help keep the noise down. I use Landrover engine mounts and even 'though there is minimal clearence between particularly the bellhousing and the tunnel I've never had it touch it. What I have had very occasionally is the nose of the diff. touch the top of the end of the tunnel going over some bumps when fully laden and going too fast.
My rear g/box mount is the standard Marina one with a modified mounting and it seems to keep the tailend of the box in check OK.As you may be able to see in the pics it tends to allow a fair degree of vertical movement but not a lot of sideways.
The other pic is of the L/R mount on the N/S at the front. Hope this gives you food for thought.

[Dane_Rescueman]

Re: Keeping gearbox under control!

Hi Hugh,
I use two large heavy duty bobbin mounts for my engine. They do not allow much movement. I think I obtained them from CBS.
My gearbox is attached the normal Ford way, albeit with a brand new mounting.

[gouldsborough7]

Re: Keeping gearbox under control!

Hugh
I'm the same as Dane - engine mountings from CBS and bog-standard Ford gearbox mounting - all new. Despite this, my local garage proprietor was able to push the gearbox up-down, when he had the car on his 6ft hoist. Rather than find an almost rigid replacement, I think I will experiment with additional rubbers.
Cheers
Mike

[Dane_Rescueman]

Re: Keeping gearbox under control!

I have just had a thought. I wonder if the stud threads on my CBS bobbins are the same thread as the gearbox support single bolt hole. If so, some time in the future I might experiment with a new steel chassis cross piece supporting the bobbin which in turn is screwed in to the gearbox. These bobbins are very strong and may provide the answer to our questions. Moll is running well at the moment so I am not planning to tear her apart again until winter '09. (unless in the intervening period, as usually happens, something goes tragically wrong with one of her widgets!).