Alfa Romeo Owners Club of Australia Forum

Technical => 160 Series (90, 75, 164 Sedans) => Topic started by: Divano Veloce on January 22, 2024, 02:04:33 PM

Title: 75 auto LSD - can it be transplanted into a 5 speed box?
Post by: Divano Veloce on January 22, 2024, 02:04:33 PM
Can the LSD from a 75 Auto be used in a manual box?

Thanks!
Title: Re: 75 auto LSD - can it be transplanted into a 5 speed box?
Post by: MD on January 23, 2024, 10:40:25 AM
It's a transaxle. The LSD component is just part of the final drive. I cannot imagine that Alfa would go to the extent to specify something different for such a low volume seller other than use what is generically available.
The automatic part is in the gearbox but the final drive should be generic.
Title: Re: 75 auto LSD - can it be transplanted into a 5 speed box?
Post by: LukeC on January 23, 2024, 12:49:11 PM
I am pretty sure they are different. I have 105, 116 and a centre sourced from an Auto Alfetta (same as a 75 box) here in the workshop. I am pretty sure the centre of the Auto Transaxle is the same as a 105.

I would have to double check though...
Title: Re: 75 auto LSD - can it be transplanted into a 5 speed box?
Post by: LukeC on January 24, 2024, 11:21:14 PM
OK... I was: that W word!  :o

They appear to be compatible.
Title: Re: 75 auto LSD - can it be transplanted into a 5 speed box?
Post by: Divano Veloce on January 25, 2024, 09:28:28 AM
Thank you Gents!

I will pull it out and report back... if i can make a "TS" out of these bits its a win!
Title: Re: 75 auto LSD - can it be transplanted into a 5 speed box?
Post by: MD on January 26, 2024, 08:51:50 PM
Good job LukeC for going the extra mile.
Title: Re: 75 auto LSD - can it be transplanted into a 5 speed box?
Post by: aggie57 on January 29, 2024, 04:19:56 PM
Yes, you can make it work but it's not a straight bolt in.  Several of us did it many years ago using LSD centres from automatic Berlina's in GTV6's.  As I recall there was a spacer needed on one side of the LSD, and the stub axles in manual boxes had a different diameter on the spline than the LSD so we needed to source some parts to sort that out.  Vin Sharp set mine up and machined up the spacer.  Excellent outcome though, well worth it.
Title: Re: 75 auto LSD - can it be transplanted into a 5 speed box?
Post by: Divano Veloce on August 25, 2024, 09:28:16 PM
The 75 Auto box does indeed contain an LSD, but it is NOT compatible with a V6 manual 4.1:1 CW/P

The V6 Auto LSD diff carrier has a 10 bolt CW
The 4.1:1 V6 manual open diff carrier has an 8 bolt CW.

The spigot diameters are different too.

As the automatic pinion rotates in the opposite direction to the manual, the differential is removed from the LHS of the transaxle and the teeth are cut in the opposite direction.

Also, the pinion head is "between bearings". Tough box!