Alfa 75 ts gearbox in 3litre

[Alfamania]

Hi, I'm interested in adding some chilli to my 3 litre 75. Since the v6 gear and final drive ratios are too tall and useless for my liking, I'm keen on swapping it for a twin spark one. Any thoughts on market value for a good second hand twin spark gearbox? I think it's a cheaper option than shortening ratios and final drive on my 3 litre gearbox....😃 I'm keen on speaking to someone that's done this before, cheers

[jazig.k]

I just did this myself recently.
Fairly straight forward swap with a few differences between the TS and 3Lt's.

The clutch from your 3lt will need to go on the TS gearbox [push vs pull setups and the doughnuts are different sizes].

The CV's are different. Simple fix is to pull the drive shafts out of the diff and swap them over. 4 bolts. The TS has M8 bolts that secure the CV to the hub and the 3lt has M10.

Swap the speedo sensors over. Swap the speedo box under the rear seat over. Swap the dash cluster over. These 3 pieces need to match each other if you want the speedo to work without hassle. The other option in a Dakota Digital SG5 calibrator.

Your best bet at doing it without spending excessively, is to buy a complete TS. The TS transaxle goes for quite a lot by itself, but for a few hundred extra you can get the whole car. Importantly, you get to drive the car to feel the condition of the box and syncros. You also get the speedo sensor, box and cluster which make the swap easier.

While it's all out, think about checking the clutch, replacing the syncros if you don't know the condition, replace the CV boots, shifter linkage rebuild and check the doughnuts and drive shaft. Although changing so much of the rotating assembly opens you to many places for a new vibration. Might be safer to change one thing at a time so if something does vibrate it should be easier to locate.

I put the 3lt transaxle into my TS too and now use it as a daily driver. Makes for a fairly boring car in comparison to the V6 but damned good on fuel!

[Alfamania]

Thanks for that, sounds promising. How much livelier is the 3lt with the ts gearbox now? How many rpm does it sit on when doing 100km in 5th on freeway? 😃 thank you

[jazig.k]

It's a gearbox, so no matter what rpm goes in the box, it will do the same coming out. About 3000RPM at 100kph, same as the TS originally revved at 100kph.

Your tacho's will read out by 30% [30% fast in the v6 and 30% slow in the TS] but apparently they have adjustment pot's behind the cluster. I'll change mine one day.

It's a whole new car. Gears run out very fast in comparison, but the car feels a like it's suitable for street driving now, rather than gearing suitable for unlimited highway use. Quick stabs at the throttle are responsive, or a couple hundred meter burst up a back street is pretty fun. On the highway, drop to 4th and massage the throttle, I get around people pretty quickly! Although, I have a bunch of other go faster mods.

If you want to feel faster, make sure your synchos are in great nick or new. Slow gear changes are slow...

[alfa75gta]

The 75 TS and 3.0 V6 gearboxes are identical save for the final drive ratio.  There is no need to change the entire gearbox, but rather, fit a 4.1:1 final drive from an Alfa 90 Super, Alfa 75 2.5 Manual or a GTV6 to the existing 3.0 gearbox.  These diffs are relatively plentiful as they are not LSD's - but the crown wheel and pinion can be used in the LSD (everyone wants a 75 TS gearbox/diff unit to fit into the aforementioned cars for the benefit of the improved ratios and LSD on the TS and 3.0 V6).  It is not too hard to do, I had it done to my own 75 3.0 by Vin Sharp.