4 speed manual gearboxes

[yobbo88]

does the yoke on a vh tailshaft fit into either an m20 or m21 gear box? right now i have an m20 behind a 173 and am going to an m21 on a 253 but dont want to change my tailshaft, or diff for that matter, not yet anyway.

any ideas?

[DANNY8]

I'm pretty sure the only differences between the M20 and M21 are the input shafts so u might be ok.

[yobbo88]

thats what the guy at the wreckers said but i have come to not trust anything he says cause he is super dodgy. i'm really hopin i can use my existing tailshaft and diff cause then all i have to worry about is the exhaust and front suspension. thanks for your answer man

[Tom_1569]

Dont you need disk brakes aswell? or do you already have them?

[yobbo88]

i dont "need" them there are v8 diffs with drum brakes, but i'm sure it would be a good idea. for now though i cant really afford it so if i go a sensible speed the car will stop. this project will be done over years when i have a more powerful engine the driveline will have the overhaul too. i make 8 bucks an hour im a 2nd year mechanic money is definately a problem

[scottydo]

if its any help, i just put a m21(the short ratio box) in my 79 vb wagon that used to have a tri-matic and it fitted good. if any thing, the front half of the tail shaft is 10mm shorter than it should be.... but will still work fine.

[yobbo88]

ok ive got the engine in basically but with 2 hassles, 1 is the sump i picked up didnt end up being a commodore sump cause it doesnt fit but thats an easy fix, what i am worried about is the clutch set up on this m21 i got, it looks like the clutch fork is reversed? my m20 clutch fork was pulled towards the front of the car by my clutch cable but this gearbox looks like it needs to be pulled towards the back? is this right? and if so how do i overcome this?

[yobbo88]

ok my sump was the right one the engine mounts are duds... i cant seem to source commodore 253 brackets that bolt to the block anywhere? i would have them fabricated but dont know what measurements to give to the metal work guys... any help guys?

[Tom_1569]

I thought 253 and 308 had the same engine mounts.... Things you learn

[yobbo88]

yeah the mounts are the same for each type of car but i had mounts for a hq and need mounts for a vh. what ive learnt is the actual rubber mount that bolts to the k-frame is almost universal but there are brackets that bolt to the rubber mount to position the block correctly in releation to the k-frame. i also learnt that i will never use my local wrecker again as he wanted $100 for the brackets and holden had genuine new ones for 40... you can guess where i told the wreckers to go...

[yobbo88]

ok the clutch fork problem again, the bellhousing between the 253 and gearbox is the hj bellhousing, which needs the clutch fork pushed towards the back of the car so im gonna either need a commodore bellhousing or a bracket behind the clutch fork for my cable to wrap around and pull from behind? anyone done anything like this?

[VRSS]

m20 and trimatic are the same length and use the same yoke.

[yobbo88]

oh yeah forgot this part my car had the ****ty mc6 gearbox and i never even knew it, thats why i'm havin problems with the tailshaft, mine is designed to reach the back of an mc6, ive bought a v8 tailshaft now though so all is good there, all im worried about today is getting a bracket made for my clutch. wish me luck

[yobbo88]

ok heres how it all went down.

-tailshaft custom made for 6cyl diff and m21 gearbox
-Engine mounts new from holden spare parts
-commodore bellhousing from wreckers (still working on getting commodore clutch fork and thrust bearing)

but yeah got it running, using the wrong clutch fork right now but it works enough to drive and change gears but the pedal sits heaps high, exhaust goes on tomorrow and then im basically done. thanks for everyones help

[Clutchy]

The early clutch uses a rod that pushed the fork the commodore use a cable to pull the clutch thats ya problem.

[yobbo88]

yeah thats all sorted i got a commodore bellhousing with the right pivot point for the clutch fork so i can use my cable setup in my car.