53 replies to this topic

[RallyRed]

Hi,

Did a search and didn't quite find the info....

 

Had the LJ track car out at an event today.

1st run, lap 2...gearbox dramas.

Here's the story....any advice appreciated. Obviously we will pull the box out and have a look tomorrow.

 

Gearbox was replaced recently with a newly overhauled box with XU1 ratios. Has been street driven several times after box put in, just to check stuff etc with no dramas.

I did notice that 1st gear was sometimes not easy to select, even when stationary.

 

Out on the track, lap 2 and when going up from 2nd to 3rd. had to have a few goes at it to get third?, a few corners later same again?.....then within a few metres, engine started to struggle / die , clutch in, rev it ok, but by now the gearbox started to feel like i was seizing up ( not the selectors, but the actual drive). Rear wheels locked up and skidded to a halt in the middle of the track.

Fortunately no one ran up my arse.

Tilt trayed off.

While being pushed back into garage, with the clutch in, there is a pronounced metallic grinding noise from under the car, however it sounds external to the box.??  With clutch out, rear wheels are locked.Jacked up rear, turned wheels back and forth by hand with clutch in,  and Locker diff feels normal.

Looked under car and flywheel etc look good and in place.

The gear selector moves around, but wont actually select a gear?

Back home and up on the hoist, all looks normal underneath, engine starts and revs fine, clutch is working, can see the fork moving etc.

Tailshaft looks normal.

 

I think I have heard about these boxes having an issue where 2 gears are selected at the same time, and thus they lock up...but I always thought that it was a 1st and Reverse issue?

 

Any ideas?

Thanks

Edited by RallyRed, 28 July 2018 - 06:55 PM.

[S pack]

Sounds like you've got a gear has welded itself to the mainshaft Col.

 

I had a similar thing happen to mine many years ago. Second gear if memory serves me correctly. Was driving along in 4th gear when the engine started to labour and an awful sound eminated from the gearbox.

Fortunately it freed itself up again and I got the car home.

Pretty sure I've still got the damaged mainshaft. I'll see if I can find it in the morning.

 

Cheers

Dave.

 

edit: Gear selector moves around but won't select a gear probably means the stick has slipped out of the selectors.

You may well have two gears selected at once.

 

Try moving the selector levers on the side of the box to ensure they are both in the neutral position.

Edited by S pack, 28 July 2018 - 08:26 PM.

[RallyRed]

ta Dave.. the selectors on the outside of the box are pretty well vertical...tried giving them a tickke with a shifta..no movement. Your comment about something welding together fits with the stuff I experienced..i.e engine breifly stuggled as the failure in the box occured, and then a lock up.
So much for the new fully overhauled box c/w new bearings etc.

[S pack]

ta Dave.. the selectors on the outside of the box are pretty well vertical...tried giving them a tickke with a shifta..no movement. Your comment about something welding together fits with the stuff I experienced..i.e engine breifly stuggled as the failure in the box occured, and then a lock up.
So much for the new fully overhauled box c/w new bearings etc.

Is this one of those H/Duty big layshaft 200kw Aussie 4spds boxes?

[caterham2]

Flywheel bolt backed out once in mine with much the same symptoms

[rodomo]

The interlocks inside the side plate pretty much eliminate the chance of 2 forward gears being selected at once...……..……………………….unless something breaks?

Edited by rodomo, 28 July 2018 - 10:50 PM.

[S pack]

The interlocks inside the side plate pretty much eliminate the chance of 2 forward gears being selected at once...……..……………………….unless something breaks?

AAAAAHHHHHHHH yes, I see your point master Yoda. This is why 1st and Rev normally are only the two that selected at once can be.

[S pack]

Hey Col,

 

Found the old mainshaft. It was 1st gear not 2nd as I was thinking.

 

 

[RallyRed]

Hey Col,

 

Found the old mainshaft. It was 1st gear not 2nd as I was thinking.

 

 

Thanks Dave..looks ugly!!     No my box not one of those 200kw advertised ones..I got it locally  ( thought there was some sort of drama with those 200 ones?)

[Bigfella237]

Jack up the arse end and put the diff on stands.

 

If one (and only one) of the gears has welded itself to the main shaft then you should find the car drives reasonably normal in that gear. So if 2nd gear is at fault, you should be able to drive in 2nd but no other gears.

 

If it's the needle rollers between the input and main shaft then it will only drive in 4th.

 

If it's the counter shaft bearings, or more than one gear on the main shaft, then it won't make any difference which gear you try.

 

Also before you remove the gearbox, drain and keep the oil from it in a clean container. You're looking for 1) how much oil was in there; and 2) how much metal is in it!

[S pack]

The g/box is rooted. Just rip the sucker out and strip it down.

[RallyRed]

Jack up the arse end and put the diff on stands.

If one (and only one) of the gears has welded itself to the main shaft then you should find the car drives reasonably normal in that gear. So if 2nd gear is at fault, you should be able to drive in 2nd but no other gears.

If it's the needle rollers between the input and main shaft then it will only drive in 4th.

If it's the counter shaft bearings, or more than one gear on the main shaft, then it won't make any difference which gear you try.

Also before you remove the gearbox, drain and keep the oil from it in a clean container. You're looking for 1) how much oil was in there; and 2) how much metal is in it!

[RallyRed]

Jack up the arse end and put the diff on stands.

If one (and only one) of the gears has welded itself to the main shaft then you should find the car drives reasonably normal in that gear. So if 2nd gear is at fault, you should be able to drive in 2nd but no other gears.

If it's the needle rollers between the input and main shaft then it will only drive in 4th.

If it's the counter shaft bearings, or more than one gear on the main shaft, then it won't make any difference which gear you try.

Also before you remove the gearbox, drain and keep the oil from it in a clean container. You're looking for 1) how much oil was in there; and 2) how much metal is in it!

Ta...yeah..up on the hoist ..its in a gear..dont know which one.

Oil was new and correct...did it before event..no leaks.

Will get to it later today and pull it out and have a gander inside. Thanks for the info too.

The g/box is rooted. Just rip the sucker out and strip it down.

yep

still interested in the flywheel bolt theory too...that should be easy to see soon

Edited by RallyRed, 29 July 2018 - 10:24 AM.

[sibhs]

Hi Col,

no idea on this one but keen to see pics and find out the cause.

 

Good luck

Marty

[RallyRed]

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[RallyRed]

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[S pack]

Wow that's one chewed up synchro ring Col. I've never seen that before.

The circlip on the end of the mainshaft might have failed.

496 cluster gear. 3.05:1 1st gear ratio M20. If it was sold to you as an XU1 ratio box you were scammed.

Edited by S pack, 29 July 2018 - 04:45 PM.

[Bigfella237]

Too little end float on the input shaft? Or I'm wondering if it's an oil starvation problem similar to what the T56's get under hard acceleration?

 

That input shaft looks like it's been bloody hot!

 

If that 4th gear synchro was binding it would've been getting hot in any gear except 4th, what sort of track was it, all lower gears / slower corners I'm guessing?

[Bigfella237]

DOH! Just realised I was looking at the wrong end, that's 1st gear isn't it..

Edited by Bigfella237, 29 July 2018 - 05:21 PM.

[S pack]

DOH! Just realised I was looking at the wrong end, that's 1st gear isn't it..

Yes.

[RallyRed]

Wow that's one chewed up synchro ring Col. I've never seen that before.

The circlip on the end of the mainshaft might have failed.

496 cluster gear. 3.05:1 1st gear ratio M20. If it was sold to you as an XU1 ratio box you were scammed.

all good...All I wanted was the 899 cluster, and that's in there

[RallyRed]

Too little end float on the input shaft? Or I'm wondering if it's an oil starvation problem similar to what the T56's get under hard acceleration?

 

That input shaft looks like it's been bloody hot!

 

If that 4th gear synchro was binding it would've been getting hot in any gear except 4th, what sort of track was it, all lower gears / slower corners I'm guessing?

Hi...Wakefield Park NSW...only in 4th on the main straight. Failed on Lap 1  1/2 . Very cold day.  Maybe you have nailed it?...taking it back to old mate tomorrow...pretty sure he will know.

I think it fits in with the 1st gear a little hard to select? 

Edited by RallyRed, 29 July 2018 - 06:29 PM.

[S pack]

all good...All I wanted was the 899 cluster, and that's in there

Looks like it has 496 on the cluster to me Col.

[rodomo]

Holden changed the "oiling" of these gearboxes over time. If I remember I'll try and get pics.

 

Also, this damage has occurred in another gear as when first is selected, it is locked to the main shaft and doesn't spin on the main shaft.

[ozyozyozy]

What oil are you using? Incorrect can cause those issues.
Super t10's can do the same thing.
There is some needle bearings and a washer that can fail there from doing the old clutch dumps.