fj 40 drive trains

[kruza wazza]

hi there, have 74 fj40 kruza with 307 in it, goes hard, ( normally !) , wairarapa 4wd club , mates with "onoescudo" off this forums, having drama with drive train back lash, could be diff, transfer box and or coupling , could upgrade to a 5 speed out of fj 60 or bj 70 but would they fit, are these gear boxs stronger, what sort of strong as gearbox would you reccomend, how do you adjust a rear diff on on of these, who mmakes new drive shaft couplings, comments all good,cheers warwick

[muddy]

5 speed out of an FJ60 is basically the same with an extra gear on the end - so no stronger. It makes the gearbox about 90mm longer so moves the transfer case rearwards needing a longer front D/S and shorter rear D/S (or a good time to flip the springs or put 60 series springs in to extend the wheelbase - that way you can keep the same rear D/S) Probably not a solution to your problem though... Diffs are all the same but may have different pinion flanges. Are you sure it's excessive backlash, and not spring wrap when you throw all that torque at the axles? You may need to brace the top of the diffs to the frame to stop them twisting on the springs...