trying to gather as much info I can on swapping a 5 speed on a 1998 R34 25gt skyline.
planning on swapping trans from stock 25GT FS5W71C 5 speed to the GTT FS5R30A 5 speed
so far I have researched and it tells me that pretty easy swap,
what i will need/to do:
swap the trans install new FS5R30A , a new SPec brand stage 1 or 2 clutch setup as the stock trans used a push type and GTT trans uses a pull type/ is this as easy as disconnecting the line to slave cylinder and reconnecting to a pull type slave cylinder, or will pedal assembly /hose line etc. or other have to be altered/changed?
I read tthat he trans mount cross member is different, but what is different with cross member? something that can be welded/by modifying a stock 25GT trans cross member?
and the drive shaft is shorter then the 25gt one, so I will shorten or source a good used GTT drive shaft
and install a GTT shifter , all else will line up, connect etc?
is this all correct? is there something I am missing?
like is the flywheel compatible?
Hi. The front slip yoke is 24 spline on an R34 GT manual. On the GTT it's 30 spline .. so not compatible.
From what I've been told, the other joint at the rear of the front shaft should be the same on both with 10mm bolts (R33 non-turbo has 8mm bolts apparently)
I haven't got exact measurements for the props but one of the photos here shows a tape measure on the turbo gearbox (32") ... Choosing a gearbox conversion for your 180SX, S13, S14, or S15
My own measurement of the non-turbo gearbox is 33.5 inches (give or take)
... so I expected the GT prop would be a bit shorter than the GTT prop but if you've got info to the contrary I'd be pleased to see it as I've got a GTT prop that would need a GT slip yoke welded on for my manual conversion.
As far as I know (and this is just stuff I've read so I'd suggest research here and the other forums to confirm) ...
Flywheel should be same between RB25 manual models
I think you're right about the different gearbox mount but not sure if it can be modded. Try and get a box and mount together. You might be able to get the prop front half included too.
Block bolts, sandwich plate, starter etc. should all line up.
Shifter will line up ok cos both boxes fit to same engine block in same chassis. Your existing GT shifter should work.
Pretty sure you're right about needing just the slave cylinder and new pull clutch kit. Fork is different between push and pull but the box should come with that.
ok, thanks, so I found a front prop shaft with the proper 30 spline for a gtt. I ordered a trans, spec clutch and a pull type slave cylinder. my last question now is what a bout speedo, how does it connect (cable/sensor etc) and will it be compatible with my current setup from 25gt r34 5 speed FS5W71C 5 speed to the GTT FS5R30A?
Nice! There's a sensor on the transmission - your box might come with it fitted so if the wiring loom plug is the same you should be ok? Otherwise, the parts catalog seems to list the same speedo pinion number for both models but I can't say for sure. What I do know is that the speedo works fine on my GT auto which is using a GTT manual ECU for my +turbo conversion. So the signals are compatible from two completely different sensors.