t spark or 3.0 gearbox

[daz]

I have read a lot about the twin spark 75 box being the best box to put in the gtv6
I am about to change my original 2.5 engine to a 3.0l and i am now thinkin should i change my gearbox as well
I have a spare taller 1984 gearbox (According to the chart below)

MPH per 1000 rpms Rpms at 60 mph
(in 5th )

1981 21.78 2,750
1982 26.14 2,300
1983 26.14 2,300
1984 26.99 2,200
1985 22.17 2,700
1986 21.78 2,750

The question i would like to ask is if i was to put in a milano 3.0 gearbox or t spark would my 2.5 clutch assembley bolt straight on(it has the milano single plate anyway)
I have read that the twin sparks cluth and yoke assembly are different does this apply to the 3.0 box aswell I know i will have to change the selector shaft to a splined type (origianl on my gtv)
The reason for my question is i have chance of buying either type of box 3.0 or twin spark but both come without the cluch assembly so im thinkin if the 3.0 needs no mods then i may be bettter buying that
So to sum up
should i go with ;
1 the original "tall box
2 the 3.0
3 or the twin spark
Again neither has a clutch

[AR4me]

I think that depends on what you are planning on using the car for. Both the 3.0 and the TS have LSD and are hence more attractive than your GTV6 box. However, the 3.0 is taller geared (as far as I know) and would therefore be better for a tourer, while the TS box would probably be better for a track car, or if you prefer faster accel. to lower RPM freeway cruising.

I'm not too familiar with the clutch mechanicals of the TS box so I can't tell if your clutch will bolt straight on.

Jes

[Alfar7]

All have the same input shaft splines. All will bolt up. The shift issue is only minor. But the speedometer drive is dependant on the year & pinion shaft end design. If you have an earlier model the end is a "gear tooth" drive. Later are strait slot for hall effect pick up.
The LSD can be fitted in any 6 cyl. case. The best easy change of all the ratios is to use an Alfetta input shaft & gears on a 6 cyl. pinion shaft with the LSD fitted. think the info below is on my website and was posted in the BB earlier. The final drive is the least important consideration as the performance depends on ratios lower. All the 6 cyl. boxes were designed for economy.

Gear Comparisons for 116 Transaxles


1st 2nd 3rd 4th 5th
Verde 3.54 stk /overall 2.87/10.18 1.72/6.11 1.23/4.36 .95/3.25 .76/2.69
Economy tall gears

Alfetta Stock 4.1 R&P 3.30/ 13.53 2.00/8.20 1.34/5.49 1.03/4.22 .83/3.40
Better performance for 4 cyl or V6

Alfetta with 3.54 R&P 3.30/11.71 2.00/7.10 1.34/4.76 1.03/3.60 .83/2.94
More performance in lower gears, fuel economy about same as stock Verde in 5th

Alfetta with 4.10 R&P 3.30/11.71 2.00/7.10 1.34/4.76 1.03/3.60 .95/3.25
More performance better driveability and acceleration in 5th

GTV6 gears & 3.54 R&P 3.50/12.39 1.96/6.94 1.25/4.43 .95/3.25 .78/2.76

Mod. Verde, 4.10 R&P
with Alfetta 3rd, 4th. 5th, 2.87/11.77 1.72/7.04 1.34/5.49 1.03/4.22 .83/3.40
Closer Ratios better performance good 5th economy Requires moderate machining & set up. My favorite setup especially if used with RJR .95 5th gear for a 3.89 overall ratio for hot street short track racing

RJR RaceTransaxle
mix of 116 type gears
with 4.10 R&P 2.00/8,20 1.23/5.04 1.03/4.22 .95/3.90 .83/3.40
Alternate 1st 1.72/1.96/2.0, alt 2nd 1.23, 1.25, 1.34. All input shaft gears pressed & welded. Expensive to build.

[daz]

Gear Comparisons for 116 Transaxles


1st 2nd 3rd 4th 5th
Verde 3.54 stk /overall 2.87/10.18 1.72/6.11 1.23/4.36 .95/3.25 .76/2.69
Economy tall gears

Alfetta Stock 4.1 R&P 3.30/ 13.53 2.00/8.20 1.34/5.49 1.03/4.22 .83/3.40
Better performance for 4 cyl or V6

Alfetta with 3.54 R&P 3.30/11.71 2.00/7.10 1.34/4.76 1.03/3.60 .83/2.94
More performance in lower gears, fuel economy about same as stock Verde in 5th

Alfetta with 4.10 R&P 3.30/11.71 2.00/7.10 1.34/4.76 1.03/3.60 .95/3.25
More performance better driveability and acceleration in 5th

GTV6 gears & 3.54 R&P 3.50/12.39 1.96/6.94 1.25/4.43 .95/3.25 .78/2.76

Mod. Verde, 4.10 R&P
with Alfetta 3rd, 4th. 5th, 2.87/11.77 1.72/7.04 1.34/5.49 1.03/4.22 .83/3.40
Closer Ratios better performance good 5th economy Requires moderate machining & set up. My favorite setup especially if used with RJR .95 5th gear for a 3.89 overall ratio for hot street short track racing

RJR RaceTransaxle
mix of 116 type gears
with 4.10 R&P 2.00/8,20 1.23/5.04 1.03/4.22 .95/3.90 .83/3.40
Alternate 1st 1.72/1.96/2.0, alt 2nd 1.23, 1.25, 1.34. All input shaft gears pressed & welded. Expensive to build.
__________________
Excuse my ignorance but what do these figures mean are they ratios (R&P ?)

[sh0rtlife]

for the swap...

you need a "dakota digital" SGI-5 this will fix the speedo drive issue(its either that or your stuck re-useing your ring and pinion which means swapping EVERYTHING in the transaxle..IMO not worth the hassle buy the 75$ sgi5 and be done with it)

the clutch...you will need to change the slide sleeve that the throwout rests on
you "should" also need to swap out 3 studs on the case as "some" of the milanos and ALL of the TS boxes(or so im told) use a different clutch slave as it pushes from the front of the box not the rear like the gtv6

im VERY happy with my TS box in my gtv6..but i still have the 2.5

does the 3.0 milano case have the LSD?>....i know the TS does..while your in there add a few extra disc's!!!!

[Alfar7]

Quote:

Excuse my ignorance but what do these figures mean are they ratios (R&P ?)

[AR4me]

Quote:

Originally Posted by sh0rtlife does the 3.0 milano case have the LSD?

[daz]

do you think the taller original gtv6 box would be ok for the 3.0 or would you reccommend either milano gearboxes again as you have concluded im not racing the car im just wanting the right gearbox for the 3.0 upgrade

[AR4me]

Personally, I would take the TS or 3.0 box because of the LSD. If you prefer lower RPM freeway cruising I would go with the 3.0 box, but if you prefer faster acceleration I would go with the TS box. The least amount of work is to stick with your GTV6 box, but then you don't have the LSD. If that isn't important to you, then perhaps the GTV6 box is a perfectly sensible choice for you. (note that swapping the input selector on the Milano box to your GTV6 input selector still requires both boxes to be split open, but it is quite simple and quick to do).
Jes

[sh0rtlife]

got one for ya....if a gtv6 had a peg leg 4:10 set in it and you swapped in a 4:10 TS unit...isnt freeway cruising going to still be the same or is 5th gear got that much more to it?

dont have a the speedo working just yet

[gtv27]

the 3.0 and TS are the same ratios except for the diff TS is 4.1 and 3.0 is 3.55 (or thereabouts) both are LSD, which is a big gain. Their closer 123 are much nicer to drive than the std gtv6 box with its stump pulling first gear. Either would be better, but I think the TS is best. Still pulls <3K at 100kph, but has lots of accel. I have a TS box in mine and the only thing I'd contemplate a change to is an all indirect autodelta box with a sequential adapter and straight cut gears and a 4.5 LSD - but of course, that would be hell on the street.

[daz]

Thanks to all on the subject. I will probably purchase the t spark box and as i i have a spare gtv box i can take my time getting the clutch and selector shaft sorted