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Lancia Montecarlo - Gearbox upgrades?

Posted: October 8th, 2006, 4:22 pm
by Snakeman
Hi All,

I am finding it increasingly difficult to select 1st and 2nd gear on my S2. I strongly suspect the syncro hub for those two gears is worn out, probably due to the race track abuse.

So I will either have to fix this trans, or replace with a more suitable upgrade ¢‚¬Å“ The Monte box has a very low ratio 1st gear (1st = 3.75, 2nd = 2.235, 3rd = 1.522, 4th = 1.152 and 5th 0.925). And the final drive could also do with allowing a higher top speed (Currently 14/52)

I have heard that, with some modification, a Fiat 131 box with go in. What options do I have?

Kind regards


Posted: October 9th, 2006, 5:40 am
by Guy Croft
Hi Geoff,

if it's any help the Vx gearbox has a taller final drive (or fifth gear?), I think. I imagine it will fit the Montecarlo.
Andrew at Omicron may have such gearboxes for sale. I am not aware of any commonality between the 131 and MC geabox, except perhaps internal parts.


Volumex transaxle in a Lancia Montecarlo

Posted: October 20th, 2006, 12:31 am
by tmvolumex
I have installed a Lancia Volumex transaxle in my Lancia Scorpion / Montecarlo Volumex and it is a great swap. The Volumex transaxles came in 2 differnt final drive ratios but the overall ratio in fifth gear is the same. The Volumex gearbox that came in the HPE VX has slightly lower final drive ratio than the Volumex box that came in the Coupe VX. The fifth gear in the HPE box is higher geared thus the same overall ratio in fifth. I do have a Volumex supercharger in my car so the higher gearing is not a problem due to the great torque developed with the supercharger. The transaxle swap makes the car a modern cruiser. In fifth gear 3,000 RPM is now 70 MPH. 4,000 RPM is 90 MPH. Gas mileage increased significantly after the swap also. The VX box does not have the tree climer first gear either.
The selector shaft, one output shaft and the speedo gear must be swapped from the Monte box over to the VX box.
"Some assembly required !!! "
Tom McGaffigan

Posted: October 20th, 2006, 11:30 am
by Snakeman
Thanks for the insight Tom!

I have now acquired an HPE VX trans.

I will almost certainly strip the whole unit down, but do you recall if it is in nessesary to strip the trans down to change the selector?

Kind regards


Posted: October 20th, 2006, 11:32 am
by Guy Croft
Hello Geoff

post some photos of this gearbox job/swap if you get time please.

Many thanks,


Posted: October 20th, 2006, 2:16 pm
by Snakeman
No problem Guy,

There is significant interest in this conversion among the Monte crowd, so I will probably end up completing a full written article with photos.


Volumex transaxle installation in a Lancia Montecarlo

Posted: October 20th, 2006, 5:42 pm
by tmvolumex
David Beale in the UK has also done this transaxle swap on his Montecarlo, he may be able to provide some local assistance.
You will need to disassemble the transaxle to swap the selector shaft and speedo gear. You will not need to disassemble the main shaft assembly.
Posted below is a copy of a post fromDavid Beale that I have ammended his post somewhat adding the speedo gear info and some other tweaks. I also found David to be very optimisic in his time estimates of completing the various tasks! He must work alot fater than me. Sorry David!

Volumex gearbox into a Montecarlo

The most important difference on a Beta box inc the VX box:
Is the selector shaft input stub, retained in the casing by a large 2.5' ring nut. The Beta box has different gear selection rod attachments, and is externally a different length to a Monte/Scorp one. You need to separate the main cases to get the selector shaft out.
It's a direct swap out, Undo the retaining ring nut withdraw and replace.
The only problem is going to be getting the ring nut undone.
Mine needed a blow torch and a strap wrench as it was a brass nut and I rounded it off even with a 6 point centre face drive socket. (I was able to get the nut off mine with no problem,you will need a modified socket though Tom M)
Next the clutch slave mounting plate bolt holes need to have there threads taped in the holes in the casing.
Swap the gearbox end cap for the Monte / Scorp one,
The Beta cap has an additional cast on mounting gusset that may interfere with the frame and I think the bottom of the stock S1 / Scorp air box. -
Swap the clutch release fork for the Monte / Scorp one, again the external
attachment is slightly different - but its a straight swap out. Use the Monte throghout bearing.
Swap the Beta right side splined drive shaft for the Monte / Scorp type drive plate for the CV mounting. It an easy direct swap out.
Undo the 4 retaining bolts and withdraw the drive shaft complete with the bearing and its retaining plate.
Remove the Montecarlo speedo gear from the Monte diff assembly and install in place of the Volumex speedo gear. (Tom M)
Reassemble the gearbox.
You will also need to set the differential bearings preload, this task may require new, different sized shims.
Good luck,
Tom McGaffigan

Posted: February 21st, 2007, 8:13 am
by Snakeman
Ok People,

I have now completed the conversion from a standard Montecarlo transmission to one with a Volumex HPE gearset and final drive

It has completly transformed the gearing and power transfer to the road. It's top speed is now frightening! It now 'feels' like a GT race car

I have photographed the process from start to finish and noted all the main points of interest and the required special tooling to complete this conversion.

A detailed report to follow

Geoff W

Posted: February 21st, 2007, 10:25 am
by Guy Croft
Hi Geoff,

Well done you!

Do the ratios of the new setup help to keep the engine in a better working powerband during acceleration (closer ratios and engine staying closer to peak torque during each change up) or is it just higher top speed?

I know that compared with Ford boxes of that era many F/L gearboxes tended to have a huge gap between 1st-2nd-3rd gear; it was a struggle to hit 60mph in second gear on any production TC I ever drove.


Posted: February 21st, 2007, 12:05 pm
by Snakeman
My road tests so far have only included local public highways so it's difficult to say, however the STD box was all revs no go. It was very close to hitting the rev limiter in top (circa 135mph), and 1st gear was a joke

The main difference on the VX gear set is the higher ratio 1st gear and the higher final drive. Despite the other gear ratios being the same as the STD box, the higher ratio final drive has made a dramatic difference I am sure it will go beyond 60 in 2nd.

My only concern is how it may affect sprint events and hill climbs.

I will know after my first few events this year

Regs, G

Re: Lancia Montecarlo - Gearbox upgrades?

Posted: September 18th, 2012, 10:34 am
by pv269
HI Tom:

was reading about the swap and what I am looking to do is use the R&P from a Monte transplanted into a 79Betacoupe box as it has the highest 5th gear.

WIll put he transmission into my Hopped up 81 Lancia Zagato. My current trans is nearly toast.

I am hoping that I don't walk into a problem with bushings or needle roller bearings as you noted.

Was wondering if you have further insight about the swap or if someone else may be knowledgeable and can add some advise.