Hi everyone...driving to the city the other day i felt like the 138 needed a fourth gear..Will i lose alot of value to the car if i put a 4speed gearbox in??.The gearshift is already on the floor...i have been told a toyota 4 speed would suit best is this right??
hi there  im no expert so my opinion may be worth nothing..but the ratio in top gear on 3 or 4 speed is the same..so nothing would be gained if you were looking  for taller gearing.  if you went to 5 speed toyota ,you'd have the ultimate but you would rarely use 5th gear because its an overdrive..the car would struggle on hills.   personally  i think the phillipino 4sp boxes from uc toranas & early commodores(4&6 cylinder cars had same box) are  nicer than the aussiebox& cheaper..my boys have thrashed em & never killed em!! but top gear ratio is still the same
 to fit a toyota 4 or 5 spd would be fairly costly     so  i suggest ya leave it as it is unless you need to replace it for mechanical reasons
     cheers trev
why not change to a taller diff ratio,that way you dont need any mods
The standard ratio is 3.89.
You could try a 3.55 or a 3.36 from later models.
They will fit into the existing diff housing okay but the standard grey might not have enough grunt - depends on your driving requirements.
An otherwise stock grey runs great with a 3.55 diff. I know blokes who have run a grey with a 3.36 but personally I think that's going a bit too far.
cheers
RET
I have run both 3.36 and 3.55s behing my stock grey and I'd agree with RET that the 3.55 is the best option. 3.36 is just a little bit too tall down low and at cruising speeds you don't really notice the difference.
David
Forgot to mention that I started with a 3.89.
Some useful numbers to consider. 3.55 is 10% taller than 3.89, 3.36 is 15%. This extra 5% is just pushing it over the edge- you always need to work to get the car up to speed. You don't feel this with 3.55 but you can hang on to 1st for longer. With the 3.89 I always felt that you'd only just be rolling and you'd have to change up.
David
thanks heaps guys..i was never interested in cars untill i bought my FC last month..now between the manual and work mates ive learnt heaps....much appreciated...Nick.A