16 replies to this topic

[Sammy D]

I've got no idea what's going on here :s

When I turn the bottom transfer gear as the engine would, the gearbox just locks up and I have no idea why! I don't think I have anything in the wrong way round, well it would be impossible to fit anything in the wrong way!! I've got no idea!

I've put together a quick video to try and make best sence of it, any help would be greatly aprechiated!

GoogleVideo upload
http://video.google....475139256218143

MegaUpload (slightly better quality)
http://www.megaupload.com/?d=PAMD2VZH

The problem is in 1st, 2nd, reverse and neutral. I'm really ready to mate box to block now, so I really need to get this sorted!

Sam

[ginigwunkle]

just seen the video so wrong comment.....sorry

Edited by ginigwunkle, 01 April 2008 - 05:15 PM.

[HARBER07]

Might seem silly but are you turning the first motion gear the right way to start with? It should spin Anti-clockwise i think (when looking at it) Or do you mean its turning the wrong way relative to the way you are turning it?

Edited by HARBER07, 01 April 2008 - 05:24 PM.

[Ethel]

When gears aren't engaged they should freewheel on the mainshaft so look to see if there's any evidence of them sticking. did you check the mainshaft endfloat? If you slip the lay shaft out you can check the gears freewheel when not engaged.

[Sammy D]

When gears aren't engaged they should freewheel on the mainshaft so look to see if there's any evidence of them sticking. did you check the mainshaft endfloat? If you slip the lay shaft out you can check the gears freewheel when not engaged.

Yeah they all turn very nicely when the lay shaft assy is out, as soon as I even rest the lay gears onto the main shaft gears, it wants to jump off the teeth (like even when the layshaft is not in the gears)

and yes, end float is fine, I'm actually using the same copper thrusts and same lay assembly as what was originally in there and the tollerances are ok.

:S

Edited by Sammy D, 01 April 2008 - 08:24 PM.

[Sammy D]

Hmmn, could it be the first motion shaft (4th gear) in anyway?

I'm really confused, all I did was take everything out, replace the double roller bearing, replace all the baulk rings and put it back together!

[Ethel]

Perhaps it's worth looking at the baulk rings if they are the only change that's likely, it does sound like something is causing one of the gears to drag on the shaft, I'd actually suspect 3rd or 4th if it causes problems in 1&2.

Have you torqued up the 1st motion shaft gear?

Edited by Ethel, 01 April 2008 - 09:42 PM.

[Sammy D]

Yeah its wierd, you can turn but it with a SERIOUS amount of force. When it's all jammed up I'll check and see if I can wiggle the baulk rings on 3rd and 4th.

Yeah both ends are torqued up to 150ft/lbs.

I might pull out 4th gear and have a closer look. Hmmmmmn! Not looking forward to taking off that nut again!

[Minicross498]

It could be something as simple as a baulk ring sticking on a gear. Try puttin a little dribble of oil on the rings to see if they are sticking. The syncro hubs look the right way round. but i dont think they can go the wrong way round. Just make sure something hasnt gone tits up with the selectors in the bottom and its trying to select 2 gears at once. Also while you've got it off the engine check the sidways play in the selector forks by wobbling the syncro hubs. i found that was a problem with crunching gears on my car.

[Sammy D]

You can wiggle the syncros a little by hand yes, or do you mean when they are in actually slid across into gear?

For some reason I am quite suspect about the first motion gear. I was fiddling a lot with it when I managed to seperate the syncro by accident just after I'd got it in the box and bearing drifted in, doh! balls and springs everywhere and getting them back together while in the case was a challenge!

If the baulk ring was sticking to 4th gear would this happen? I'm lying in bed right now but I'm tempted to get dressed and get out to the garrage!

[Minicross498]

There should be very little play in the selector forks wen in neautral 0.5mm each way i suppose. Lube the syncros up a bit and try it. is if was sticking on 4th it would bugger the whole box up. if that doesn't cure it Take it out start again. double check what you have done. its not worth taking the risk. its not exactly a 2 min job to get the box out again is it. im gettin kinda good at this mini g/box stuff. im re building mine at the mo from the minicross car. 2nd time in 6 meetings. 2 selectors forks, 3 baulk rings, 1 syncro hub and a new 3rd gear this time. bloody minis!

Edited by Minicross498, 01 April 2008 - 10:41 PM.

[Sammy D]

Ok, I'm going to chuck lots of oil at it and see what happens.

Should the diff actually be turning though when its in neutral? :S

[Sammy D]

Ok, update...

With it all in neutral I can hold the syncrohubs and wobble them about 2mm each way. This is whats causing the locking up. The syncros are wobbling accross and the baluk rings and gripping on the tapers of the gears.

That's not good, I need new syncro hubs and main shaft.

[RobJaxon]

expensive job i must say!

[Minicross498]

Ok, update...

With it all in neutral I can hold the syncrohubs and wobble them about 2mm each way. This is whats causing the locking up. The syncros are wobbling accross and the baluk rings and gripping on the tapers of the gears.

That's not good, I need new syncro hubs and main shaft.

Changing the selector forks will stop the wobble. And they are much much cheaper. It would probably be ok when its being driven properly.