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MT75 Installation and Removal with Body in place

PostPosted: Wed Nov 11, 2009 6:11 pm
by gerrym
Hi, looking for others experience of removal and installation of the MT75 gearbox in and out of a Spyder chassis.

Many of these will have been built-up into the chassis without the body in-situ, then the body dropped into place.

I'm trying to see what others experience has been in a service situation (eg to replace clutch plate).

I know I can't remove the engine separately, so my starting point is that the engine and MT75 gearbox are coming out as a unit.

The sticking points I have identified are:-

a) difficult access to bolt heads for the gearbox output flange to driveshaft flange (originally had a sliding yoke which dropped out without any fasteners)

b) The gearbox lever cannot be removed from inside the body, hence the gearbox must be lowered a long way down

c) the gearbox rear mount clashes with the chassis lower frame members (Spyder space frame chassis)

d) to tilt the top of the engine upwards, the removeable chassis brace (the one sitting beneath the engine bulk just below the heater area) on the Spyder chassis must be removed.

I'm not inclined to give up on these problems and resort to body removal for servicing a clutch.

Anybody managed to overcome these issues.



Re: MT75 Installation and Removal with Body in place

PostPosted: Wed Nov 11, 2009 7:16 pm
by Spyder fan
Hi Gerry,
How many miles have you done to need a clutch change?

When I spoke to Andy at Spyder about the gearbox that had to come out of the Classics Monthly car, he said the route out for the gearbox depended on the quality of the body shell. Literally what he meant was they are so practised at getting bodies on and off at Spyder that its no more than a 3 hour difference between taking it out via the engine bay or lifting the body off. As they could 'potentially'do a lot more damage to the paintwork than 3 hours worth labour would cost, they normally go the body off route for safety. Of course they have the room and the proper lifting equipment, so it's an option for them to take this route.

To take out via the engine bay I suspect you need to be jacked up and supported to allow the gearbox to fall low enough to release the gear lever, the engine and box would then need to come out at an angle causing you all sorts of problems as you have stated: The following is a bit of lateral thinking, not sure if its practical:

Remove the centre console and consider cutting the gear lever as near to the gearbox as possible, this will enable you to remove the engine/gearbox unit without too much of a struggle........ keep the cut off part and once you have everything out, take the gearlever stumps to a machine shop for them to modify into a 2 part removeable item, the joint of which will be hidden in the gearlever gaitor.


Re: MT75 Installation and Removal with Body in place

PostPosted: Wed Nov 11, 2009 8:15 pm
by gerrym
Alan thanks for the reply and suggestions. I've posted the clutch as a "hypothetical" example. Presumably however one would want to consider the servicing implications of anything bought or built.

I have had my engine/gearbox combo out but it was a pretty horrific struggle. Not one I'd entrust even to my very well equipped and sympathetic local garage. However if the accepted method is to remove the body first because this is the only methods that works, then its better for owners to know in advance....

Regarding your suggestion for the gear lever, this is one area that needs a rethink. I've already cut down the lever to a 1/2" UNF threaded stump. The other half of the gearlever now has a 1/2" UNF female socket loctited in place. This mod considerably eases the angle required to remove the gearbox and was done in the workshop prior to installation into the car. Minor drawback is that the gearlever could unscrew in service (any ideas on a locking system, wire, split pin???).

I've also modified the Ford rubber support with captive nuts. On the tailshaft of the MT75 gearbox casing I've added M10 thread inserts. The idea is to have all the mounting hardware removed from the gearbox during installation and then ease the job of screwing it all back together from below.

Still looking for a neat solution to the upper chassis cross-brace removal.



Re: MT75 Installation and Removal with Body in place

PostPosted: Wed Nov 11, 2009 9:50 pm
by stugilmour
Gerry & Alan, I really like the idea of making the shift lever 'splittable'; will have to consider with mine. Have the body off now and engine/transmission is very easy to put in and out single handed, but was not thinking ahead. Like the retaining idea of a split pin or threaded Allan head gudgeon pin if you can manage the drilling and tapping with the lever stub in place? Thinking in my case my engine lift would not go high enough if I had to have the frame a foot in the air to get the shift lever out from under the car.

That nasty brace on the top of the frame seems to be a real issue. Note my frame does not have one. The frame is about a year and a half old, so assuming it is the latest generation. Wondering if calling Andy to see what may be involved in eliminating this brace is the way to go? Looking on the photo's on the Spyder site and a few previous posts where we discussed this item, they may have re-arranged the front frame rail design a bit to eliminate the brace.

Having lowered the assembly in several times on about a 20 to 30 degree angle, I wonder if there is enough clearance above the frame to top of tunnel on the body to even get the darned thing in with the body in place? I guess if Alan says Andy has done it this way it is possible, but thinking a pretty high degree of difficulty. Mine hangs on a cast protrusion right side of the rear housing immediately aft of the joining flange, hence need for the angle.

I guess I better make sure I do everything I can to make body removal as easy as possible!

Gerry, I think I fabbed a reasonable solution to the starter motor clearance problem; thanks again for all the help. I ended up cutting out the middle portion of the offending brace and making up a bolt-in piece attached to the welded stock brace stubs. Have sourced a mobile welder if needed, but thinking bolt-in solution is OK, certainly 'til I get the body back and can accurately check clearances to the fibreglass. Visited the body today, and ready for paint in about a week!

Re: MT75 Installation and Removal with Body in place

PostPosted: Thu Nov 12, 2009 9:42 am
by GrUmPyBoDgEr
Phew Gerry,

that's one long Snagging List you've drawn up there & I'm sorry that I can't provide any solutions but now feel more inclined to keep the Twin Cam gearbox in my Elan.
I've been very interested in the newly developed 6 speeder that's previously been discussed.
I suppose that with that Box similar fitting & removal problems can be anticipated?
These questions have been mentioned rather loosely on that thread but to date I don't think any answers have been provided?
I hope that this posting (Hijack) of mine doesn't lead your thread into a wildly different direction but that the old thread's open questions gets some answers sometime.


Re: MT75 Installation and Removal with Body in place

PostPosted: Wed Nov 18, 2009 8:20 pm
by gerrym
For access to the fasteners holding the top removeable brace in place, I might be able to use one of these.

Has anybody got one of these 90 degree drivers?. Do they work OK, is there a UK supplier for Cal-Van tools?


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