Differential swap

bobsiopener · #1 (**permalink**) 12-21-2007, 07:04 AM

Hi,
I have an 84 GTV6, with the 3.42:1 axle ratio and an 87 Milano Platinum with the 4.1:1 LSD that i use as my daily driver. I thought that it would make sense to swap the differentials so that my GTV6 would have the sporty ratio and the added benefit of the LSD and my daily driver would benefit from the lower cruising rpm on my long highway commute to work.
I glanced over the differential overhaul procedure to get an idea of what is required. It looks like you have to take the whole trans apart to get access to the diff. Is this the case?
If thats the case then i guess the best solution is just to swap the whole transmissions. I think that there could be some problems with the gear selectors. Am I correct in assuming that gear selector shaft (from shifter back to trans) is diffrent lengths in the Milano and GTV6? I was wondering if it would be best to swap the gear selector input shaft of the trans when i do the swap to retain the isostatic in the Milano and the simple selector in the GTV6. Since i have both cars and money is tight for me at this time i was trying to do this without having to get anything fabricated.
thanks,
Bob

barbone105 · #2 (**permalink**) 12-21-2007, 10:55 AM

Bob, you can easily swap the diffs. need to drop the ps axle, rotor caliper, and remove the side cover on the diff. case. diff pops right out. have to swap ring gears as well (they should stay with their respective pinion gears).
is a lot of work but you'd have to do most of it anyway to swap the transmissions.
andy

barbone105 · #3 (**permalink**) 12-21-2007, 10:57 AM

the shift rods are different lengths (GTV6/75). however, i think can attach the non isostatic shift rod to the isostatic linkage - however, not sure.
i do know, will need some serious BFH massage to the underside of the gtv6 to clear the isostatic linkage.
imho, probably not worth the work.
andy

**Alfar7** · #4 (**permalink**) 12-21-2007, 01:53 PM

Your 1984 GTV6 came with a 4.1 R&P. You have some work ahead of you but swapping the diffs is out, and swapping the LSD will require re-setting bearing preload and backlash. Best not to go there either.

If you remove your transaxle You can have a knowledgable Alfa mechanic swap the GTV6 shift rod from yours to the Plat box. You have a better set of gear ratios in the Plat box and the bearings are bigger. Your spedo drive unit should work in the Plat case. The Plat`s sender will not drive your Speedometer i don`t think.

As for the As for the crappy Plat/Verde Iso shifter unit, toss it away. Your earlier unit is much more dependable and exact.

This is not a simple swap.
Good luck
Rj

bobsiopener · #5 (**permalink**) 12-21-2007, 02:21 PM

Hi Richard,
The stock 84 might have come with a 4.1 but i can assure you that is not what mine has. I was thinking of swapping the shifting rods and maybe swapping the 2nd gear syncro for a fresher one because its pretty bad on the plat. Swapping the whole trans does seem like the simplest solution at this point.