Monaro gearbox
Discussion
mfp4073 said:
Just a couple of quick questions on the T56 as fitted to Monaro's.
For those of you that have had them rebuilt, do they now shift from gear to gear smoother without balking or having that bloody awful (slight) crunching noise as the gears start to mesh? and can they be rebuilt to a tighter tolerance, so you can reduce the (PIA) huge amount of back lash from the output shaft?
Regards John
Any "lash" you think you're feeling from the output shaft is nothing to do with the gearbox, and everything to do with the propshaft/diff.For those of you that have had them rebuilt, do they now shift from gear to gear smoother without balking or having that bloody awful (slight) crunching noise as the gears start to mesh? and can they be rebuilt to a tighter tolerance, so you can reduce the (PIA) huge amount of back lash from the output shaft?
Regards John
And how they might shift after a rebuild really depends how bad it is now, and where the problem actually lies. Could be within the trans, oil, clutch etc
But they absolutely should not be crunching
[quote=stevieturbo]
Any "lash" you think you're feeling from the output shaft is nothing to do with the gearbox, and everything to do with the propshaft/diff.
Thanks for info steviturbo,
The only bit of gear crunching I get now is shifting from 1st to 2nd gear when it's stone cold, but it is hardly noticeable. Once warm it's fine.
The diff has been totally rebuilt so that's in order, which leaves the prop. The rubber donuts look OK, but I might change them at some point together with the centre carrier bearing as they are all original. Hopefully it will then be a little less clunky....or not!
Thanks again......John
Any "lash" you think you're feeling from the output shaft is nothing to do with the gearbox, and everything to do with the propshaft/diff.
Thanks for info steviturbo,
The only bit of gear crunching I get now is shifting from 1st to 2nd gear when it's stone cold, but it is hardly noticeable. Once warm it's fine.
The diff has been totally rebuilt so that's in order, which leaves the prop. The rubber donuts look OK, but I might change them at some point together with the centre carrier bearing as they are all original. Hopefully it will then be a little less clunky....or not!
Thanks again......John
The T56 is always clunky when cold. It's the old Borge Warner T5 'box that used to be fitted to Cosworths etc that the rights were bought for and made into a 6 speed, hence the T56 name. Mine was clunky and feeling like it was shot but a change of oil and a new LS7 clutch fixed it just like yours but they are notchy and a little stiff when cold, then when they warm up they free up
Aitch 'H' said:
The T56 is always clunky when cold. It's the old Borge Warner T5 'box that used to be fitted to Cosworths etc that the rights were bought for and made into a 6 speed, hence the T56 name. Mine was clunky and feeling like it was shot but a change of oil and a new LS7 clutch fixed it just like yours but they are notchy and a little stiff when cold, then when they warm up they free up
Thanks that's good to know, I think as a T56 goes I have a good one after all...John
I would be ensuring 100% your clutch is not dragging before pulling anything apart. And then I'd be exploring oils.
If the problem was only with 1 or 2 gears, then yes you could envisage a box issue. If it's more gears, all the gears....or worse going down the gears ( when synchros/baulk rings work hardest ) again, this should give a clue as to where a problem may lie.
From a standstill, how does the car go into gear....any gear ? including reverse ? It should go very easily.
And if not...with the engine off does it select a gear any differently ? ( allowing for fact parts are not moving and may not be aligned first try )
And the clunking...large rwd diff and heavy propshaft, to a degree there will always be some lash. The rubber donuts on the shaft should help absorb some of this though and mask it from the driver. You could maybe have the CWP lash set on the tight side of things as this will remove some of the free movement the prop sees during on/off drive, but there will always be some
If the problem was only with 1 or 2 gears, then yes you could envisage a box issue. If it's more gears, all the gears....or worse going down the gears ( when synchros/baulk rings work hardest ) again, this should give a clue as to where a problem may lie.
From a standstill, how does the car go into gear....any gear ? including reverse ? It should go very easily.
And if not...with the engine off does it select a gear any differently ? ( allowing for fact parts are not moving and may not be aligned first try )
And the clunking...large rwd diff and heavy propshaft, to a degree there will always be some lash. The rubber donuts on the shaft should help absorb some of this though and mask it from the driver. You could maybe have the CWP lash set on the tight side of things as this will remove some of the free movement the prop sees during on/off drive, but there will always be some
stevieturbo said:
I would be ensuring 100% your clutch is not dragging before pulling anything apart. And then I'd be exploring oils.
If the problem was only with 1 or 2 gears, then yes you could envisage a box issue. If it's more gears, all the gears....or worse going down the gears ( when synchros/baulk rings work hardest ) again, this should give a clue as to where a problem may lie.
From a standstill, how does the car go into gear....any gear ? including reverse ? It should go very easily.
And if not...with the engine off does it select a gear any differently ? ( allowing for fact parts are not moving and may not be aligned first try )
And the clunking...large rwd diff and heavy propshaft, to a degree there will always be some lash. The rubber donuts on the shaft should help absorb some of this though and mask it from the driver. You could maybe have the CWP lash set on the tight side of things as this will remove some of the free movement the prop sees during on/off drive, but there will always be some
In September of this year I had a new clutch fitted (LS7) together with new gearbox oil (Royal Purple) and two new Pedders half shafts.If the problem was only with 1 or 2 gears, then yes you could envisage a box issue. If it's more gears, all the gears....or worse going down the gears ( when synchros/baulk rings work hardest ) again, this should give a clue as to where a problem may lie.
From a standstill, how does the car go into gear....any gear ? including reverse ? It should go very easily.
And if not...with the engine off does it select a gear any differently ? ( allowing for fact parts are not moving and may not be aligned first try )
And the clunking...large rwd diff and heavy propshaft, to a degree there will always be some lash. The rubber donuts on the shaft should help absorb some of this though and mask it from the driver. You could maybe have the CWP lash set on the tight side of things as this will remove some of the free movement the prop sees during on/off drive, but there will always be some
I can select all gears easily with the engine running, but for reverse it is better to select second gear, then put it into reverse. If I try to go in reverse straight away it will go in but with a loud thump.
Without the engine running gear selection is as you have stated, 1st gear is a bit awkward, but everything seems OK.
The only noise issue I have is the slack in the drive train, I really can't get my head around that.
I have always had RWD cars and this is the only one that makes a loud thump when on/off the throttle especially when driving around town.
I have considered a one piece prop shaft or even solid replacements for the two rubber donuts, but my knowledge about this comes stops right there!(not to mention the cost of buying something that may not make any difference)
John
You should hear mine.....big 8.8" axle, lots of play, rose jointed....it clunks like f
k ! and I do hate it. But it's strong....so I suffer it.
I really doubt a 1 piece steel shaft would make much difference...and they do come with very much reduced speed ratings due to their length
An alloy or carbon shaft would probably offer a better improvement over a steel shaft. Of course if either of those move away from rubber drive and all metal....you may lose any gains you think you would see in refinement.
DSS do some alloy shafts, and there are sellers on ebay where you could use the global shipping program ( DSS charge huge shipping prices directly )
eg...but do note the 150mph critical speed. You cannot run this shaft if you will ever see this speed.
http://www.driveshaftshop.com/domestic-driveshafts...
Carbon should have a much higher critical speed, but you'd need to check with them first. Carbon should absorb a lot of the clunkiness
http://www.driveshaftshop.com/domestic-driveshafts...
But if things are clunking into reverse etc...either the baulk rings on that gear are done....or the clutch is not releasing fully.
Not really something easy to diagnose without getting dirty. If you could gain access to the flywheel surface either via starter hole, hole in the bellhousing or whatever. Have someone press the clutch and then from underneath inspect how free the friction disc is, even try and rotate it with a long screwdriver or something using the edge.
Getting a visual on such things whilst awkward, at least gives you certainty whether it is releasing properly or not.
k ! and I do hate it. But it's strong....so I suffer it.I really doubt a 1 piece steel shaft would make much difference...and they do come with very much reduced speed ratings due to their length
An alloy or carbon shaft would probably offer a better improvement over a steel shaft. Of course if either of those move away from rubber drive and all metal....you may lose any gains you think you would see in refinement.
DSS do some alloy shafts, and there are sellers on ebay where you could use the global shipping program ( DSS charge huge shipping prices directly )
eg...but do note the 150mph critical speed. You cannot run this shaft if you will ever see this speed.
http://www.driveshaftshop.com/domestic-driveshafts...
Carbon should have a much higher critical speed, but you'd need to check with them first. Carbon should absorb a lot of the clunkiness
http://www.driveshaftshop.com/domestic-driveshafts...
But if things are clunking into reverse etc...either the baulk rings on that gear are done....or the clutch is not releasing fully.
Not really something easy to diagnose without getting dirty. If you could gain access to the flywheel surface either via starter hole, hole in the bellhousing or whatever. Have someone press the clutch and then from underneath inspect how free the friction disc is, even try and rotate it with a long screwdriver or something using the edge.
Getting a visual on such things whilst awkward, at least gives you certainty whether it is releasing properly or not.
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