[maloo11]

Jus got my t case back with 6.5s, put it in and im getting a tiny bit of drive, enough to move the car, when in nuetral? What the? If i put my foot on the brake it stops moving (doesnt stall or anything), jus idles normally. It only happens when i put it in nuteral(gearbox) and as i let my foot of the clutch it generates drive. Whats going on?

[Nik]

Haha that had me stumped for ages, found the answer in some obscure thread on somthing else.
Its the gears turning in the gearbox whipping up the oil and it turns the next gear even tho you are in nuetral!
I use to drive down my driveway in nuetral on cold mornings when the oil was still thick.
I cant idle in neutral on initial start up (no choke) because of this!
Nik

[maloo11]

And i take it a bit of a whine is just the gears meshing in together?

[31zook]

yep the whine will go away, but nik i think your wrong, so you prob's put some bigger tyres on it and the gearing was out the window, then you put the 6.5's in and now it's possible over geared, and there is a little drag in the clutch from before....

[Gwagensteve]

No 31zook, Nik is right. my car runs 6.5's and 5.12 diffs and creeps merrily along at idle for the reason Nik stated.

It's is 100% not clutch drag. Clutch is engaged (i.e foot off the pedal) , gearbox in neutral, transfer in low range, car at idle.

It's the effect of very low gearing and the drag of the gears being turned by the oil in the transfer.

Steve.

[31zook]

well there you go, you learn something everyday

[matty87]

what is happening is similar to how a slush box auto works loosely of course.

[mrw82]

ALL the gears in the gearbox (and transfer for that matter) are in constant mesh, it's not the actual gears that make that horrible sound when you fuck up and 'crunch the gears'/'brush the teeth'... its drive teeth which are part of the gear cluster and synchro hub that the shift fork engages that grind.

anyways.... it's beacuse of this constant meshing of the gears if theres enough resistance provided (ie. through thick oil in the bearings) it can provide drive and make the car move.

see in the pic below the gears are in constant mesh and spin freely on the input shaft with needle roller bearings. the collars on the input shaft are engaged by the shift forks, these collars all rotate with the shaft, so when you engage it onto a gear (by moving forwards or backwards) that gear is then locked onto the shaft with it

All the gears on the output shaft are locked solidly onto the shaft (all except 5th and reverse are actually one big cluster, the 5th and reverse cluster are fitted onto a spline)

[31zook]

Mine's a constant drive Gbox

[303zuke]

A thinner gear oil like Castrol VMX80 will put a stop to it.

During winter in this neck of the woods, I use ATF in the gearbox. Works a treat and the synchros love it. No more crunching into a gear on a cold morning. Dump it for summer and go back to VMX80.