another tremec/gearbox/clutch problem

[Disturbed1]

i recently put my car back together after getting some1 else to rebuild the box... i had the syncro mating surfaces shot blasted with 120 grit garnet so they brass syncros were grippy as fuck and locked up easy as... now the gearbox was assembled and now ive got the whole car bolted together i have encounted a major problem..........

while the gearbox was being rebuilt, i also had the clutch looked at and was shown signs of wear... the clutch is a osgiken twin plate)

we had to machine 1.5mm off the flywheel cage to preload the pressure plate properly so the fingers went flat when bolted up. other then that no other changed besides resplining the clutch plates to 26 spline sinc ei upgraded my input shaft on the box at the same time it got rebuilt

so what problems am i having

with the car jacked up on axlestand, i start the car = all sweet.
press the clutch in and the clutch rattles like a typical twin plate = nothign unusual, feels nice and normal
now slowly try select a gear by slowly and softly moving stick into a gear and allthough it will not go into gear - even with considerable force, the rear wheels start driving

if i turn car off and try put into gear - it is also near on impossible, even if u try force it.
however if u rock car back and forth, they will go into gear easy as (if u rock car back, slips into gear - let it rock forward back where it was and u cant take it back out)

if u put the car into gear with motor off and start the car - the car is truying to drive itself nstantly while cranking. if the car is runnign in gear on axle stands and u press the clutch in - the wheels wont stop spinning and its impossible to stop them by spinning (even with handbrake it just stalls motor..

now i know its runnign a sintered bronze spigot bearing which was a tight fit, slipped onto input shaft easy enough, but was failry sticky to spin. the gearbox and all slipped on easy enough when assembling, but i know this wont be helping matters at all.

so basically not sure what could be the problem

either 2 grippy syncro surfaces
input shgaft been preloaded to much
spigot bearing to tight
clutch not releasing (havent touched the slave/master setup at all)

anyone else had similar situation??

i know i had problems with syncros coming loose in a r154 jamming the input and output shaft but this made the wheels want to drive even when in neutral. so dont think its the same as what im sufferign now.

[petergoudie]

Could be the spigot bearing. I was caught like this on a piece of machinery. It might just spin on the shaft when out of the car but as its a press fit into the flywheel, the inside diameter (or bore) reduces and it can stick on the shaft.

[Disturbed1]

yeah, was trying to relate the spigot bearing to not being able to get into gears with the car off though.......

[thechuckster]

if the input shaft is grabbing on the spigot bearing, it would be like the clutch being engaged and having a direct connection from motor to input shaft.

[Disturbed1]

any recommendations on the clearance/tolerance for a bronze spigot bearing??

[thechuckster]

is that bearing a plain bush, or does it have a set of rollers inside it?

[Disturbed1]

is sintered bronze (so plain bush)

apparently roller bearings are bad and can greate to much drag. and a 12/32 sealed ball bearing contains to small of balls to support the load go figure

[allencr]

any recommendations on the clearance/tolerance for a bronze spigot bearing??

If it was lubed before the trans was installed, the trans didn't need to be pulled on the last 20mm with its bolts, and the no-clutch-release problem happened immedietly, then I'd never guess that it was a pilot/spigot bearing problem & especially one that was seized enough to stall the engine.
The clutch's noisey floater plate suggests that it is disengaging completely, so I'd guess that there is flywheel to disk interference. The stuff you've done inside the trans is a separate issue.

[Disturbed1]

If it was lubed before the trans was installed, the trans didn't need to be pulled on the last 20mm with its bolts, and the no-clutch-release problem happened immedietly, then I'd never guess that it was a pilot/spigot bearing problem & especially one that was seized enough to stall the engine.
The clutch's noisey floater plate suggests that it is disengaging completely, so I'd guess that there is flywheel to disk interference. The stuff you've done inside the trans is a separate issue.

i can bolt the bellhousing onto the back of motor with clutch fork on seperatelt before mounting the box.

when i went to put the gearbox on, it fell 10mm short of going all the way on since everything is so accurately sized etc (spigot bearing/input shaft retainer...), ended up puttign a metal extension (read: pole) onto the shifter fork and pulling back on it to release the clutch plates at which point the box just slipped all into place nicely.

have driven the car once which involved starting it up in gear (2nd) and driving down the street only to do a uturn and drive up my steep driveway which is to steep to push the car up. the spigot bearign was squeeling like a bitch so is obviously not right.

[Disturbed1]

guessign smartest thing to do first would try increase the throw on the clutch just to rule out the clutch not opening enough to disengage first.

the gearbox is yet to crunch on me no matter how hard i have tried to unsuccessfully force it into gear while the car is running (either on stands or on the ground)

[allencr]

the spigot bearign was squeeling like a bitch

The spigot/pilot will ONLY turn when the clutch is completely disengaged and could only make noise if & when it is turning.
If the clutch pedal was not near or on the floor, if the car was moving and if the clutch is not disengaging as you've written, then that squeal is definitly coming from some other bitch!!

[thechuckster]

apparently roller bearings are bad and can greate to much drag. and a 12/32 sealed ball bearing contains to small of balls to support the load go figure

i call shenanigans on this - a roller/ball-bearing spigot bearing is not carrying any 'load' except when the input shaft wants to flex.

plenty of high-torque 4WD's use proper bearings for spigots. All of my cars have had proper spigot bearings and the only clutch issues i've had were throw-out bearings.

[Disturbed1]

have neglected this issue for a while

took the motor and box out yesterday.

pulled the gearbox off and the clutch off and didnt notice anything strange

went to take the spigot bearing out and it basically fell out, pulled it out with finger with ease so the tight fit on the input shaft must have become an interference fit by time the spigot was hammered into the crank and the spigot has been wizzign around in the crank and worn it down considerable. so i guess that was the high pitch squeel i was experienceing

anyway. made up another 1

smached it in crank, double checked the ID and it was spot on

put the clucth and bellhousing and fork etc all on minus the gearbox. sat it in thew engine bay - hooked up the slave and made sure the clutch plates were releasign fine, which they appeared to be. could stick my fingers up through the relese bearign and wobble both plates up and down freely.

so pulled the motor back out, bolted the gearbox on good and proper then while sitting on a hoist/tire out of the engine bay, while the gearbox was in gear, i stuck a metal pole on the clutch fork and yanked it back (effectively pressign the clutch and disengaging it) while dad spun the crank over, yet the output shaft on the box still spun with the engine. with the yoke in - no matter how hard i tried to restrain it i couldnt.

im thinking this isnt normal so holdign back from putting the motor in yet again

anyone got any new thoughs?

[RA35GT]

Hey dood,

Remove the clutch plates and pressure plate. Reinstall gearbox.
Spin engine make sure output doesn't spin. Will rule out spigot bearing. (Already ruled out I think)

Install pressure plate (with no clutch plates) and whack box back on.
Spin engine make sure output doesn't spin. Will rule out clutch plate dragging.
(I'm thinking maybe the fingers on the pressure plate can drag onto the input shaft? You can prolly check this with a clutch plate aligning tool and measure the clearance. When the pedal is pressed does the fingers get closer to the input shaft? )

Never heard of it happening but just thinking of the possibilities.

[thechuckster]

- remove gearbox
- fit a borked clutch centre over the input shaft
- put gearbox in neutral
- rotate input shaft
you should be able to hold output shaft with one hand and it shouldn't rotate.

Assuming your home-made spigot bearing is not grabbing on the input shaft (i still don't see why you need a brass bush when a sealed roller bearing - as supplied with most clutch kits - would do the job?), i'd say your gearbox is not right.