try this
john
Am i correct in thinking that the 6 speed was a proper crash box , as i was a young lad ‘passenger’ in my dad’s, i’m sure that when he upshifted gears, that he let the revs ‘die down’ before shifting into gear 
Also he used to say they would start ‘first time’ no matter what the weather 
Hiya …yes they had a crash box. i worked at Adams butter and when they had their first Atkinson(220 ■■■■■■■ and fuller box) i was showing
one of their older drivers how to change gear.( instead of letting the revs drop to tickover you just changed as fast as you could) i went
round the yard two or three times with a loaded trailer with stacks of revs(and the dynair fan also howeled) the transport manager(who could,nt
drive) banned me from driving any more trucks and was only let work in the garage he did,nt seem to notice that the other drivers was driving the
atkinson diffrentley to the AEC,s if adams rented odd lorries like gate change scammells or electric change ones the drivers would ask for a
drivers mate. they would ask for me then i would drive for them as most of them was used to AEC crash boxes.
John
Sorry to have to pour cold water on the ‘AEC’s used crash boxes’ statement but this is something I’ve come across quite a bit, many drivers thought they were using a crash box when infact it was a Constant Mesh box, the Constant Mesh box has been around for a very long time, well before the Second World War and AEC along with many other makers have been using them since then. There are basically three types of manual gearbox, Crash, Constant Mesh and Synchromesh, we all pretty much know the Syncro its the same as in our cars. The confusion is between the Crash and Constant Mesh, with both a need to double de-clutch was needed and its because of this action that some drivers presumed they were driving a crash box, true they might well have played tunes on it like a motorway pile up but it would have been a Constant Mesh and somehow just the fact that de-clutching was needed the myth has prevaled for many years that these were crash boxes. As regards the AEC Mandator Mk V like the one shown in the Adams Butter pic it came with a 5 speed direct drive top constant mesh box, but could also have and frequently did, a 6 speed overdrive type of the same box, so sorry constant mesh not crash. Graham Edge’s excellent book on the AEC Mandator does though mention Adams Butter having Mk V Mandators on trunk as prototypes to evaluate fast and sustained motorway driving on parts of the newly opened M1 (early 60’s) and were fitted with high speed diffs and higher than normal revving engines with special low friction pistons, no gearbox is mentioned but this couldn’t be done with a true crash box but with the 6 speed overdrive constant mesh. Hope this has helped clear that myth, I’ve so often heard guys say they had a crash box in the Sedd Atki, Transcon or even Ergo Cabbed makes when trucks made thirty years or so before these from the same makers were using constant mesh boxes. Cheers Franky.
Frankydobo:
Sorry to have to pour cold water on the ‘AEC’s used crash boxes’ statement but this is something I’ve come across quite a bit, many drivers thought they were using a crash box when infact it was a Constant Mesh box, the Constant Mesh box has been around for a very long time, well before the Second World War and AEC along with many other makers have been using them since then. There are basically three types of manual gearbox, Crash, Constant Mesh and Synchromesh, we all pretty much know the Syncro its the same as in our cars. The confusion is between the Crash and Constant Mesh, with both a need to double de-clutch was needed and its because of this action that some drivers presumed they were driving a crash box, true they might well have played tunes on it like a motorway pile up but it would have been a Constant Mesh and somehow just the fact that de-clutching was needed the myth has prevaled for many years that these were crash boxes. As regards the AEC Mandator Mk V like the one shown in the Adams Butter pic it came with a 5 speed direct drive top constant mesh box, but could also have and frequently did, a 6 speed overdrive type of the same box, so sorry constant mesh not crash. Graham Edge’s excellent book on the AEC Mandator does though mention Adams Butter having Mk V Mandators on trunk as prototypes to evaluate fast and sustained motorway driving on parts of the newly opened M1 (early 60’s) and were fitted with high speed diffs and higher than normal revving engines with special low friction pistons, no gearbox is mentioned but this couldn’t be done with a true crash box but with the 6 speed overdrive constant mesh. Hope this has helped clear that myth, I’ve so often heard guys say they had a crash box in the Sedd Atki, Transcon or even Ergo Cabbed makes when trucks made thirty years or so before these from the same makers were using constant mesh boxes. Cheers Franky.
Hi Franky ,
not doubting your mechanical knowledge 
, but the reason i asked was having driven eaton- fuller & spicer constant mesh boxes myself, when upchanging it is a rather simple procedure of double de clutch action to change gear, but like i mentioned a different method was required in the AEC i.e letting the revs die down before moving the lever into gear- making rushed changes impossible . Any explanations
Toni it was because the gear ratio’s were a lot closer together on the fuller,eaton and spicer boxes but the revs still had to drop but not as much were as on the older 4,5 and 6 speed boxes had wider ratio’s and with the overdrive top there were some wagons which would not take top while over 40 mph unless really flat road. I am no mechanic it is only my opinion and I have never drove one of the latest wagons as I have been off the road over 10 years but did drive most wagons from the late 50s to the 90s and I still reckon the eaton twin splitter was the best gear box.
cheers Johnnie
Sammy gave a good answer to your question Tony, I can only add we have to take into account many variations such as different engines, drive lines etc as to why gear changing can differ so much from one make of vehicle to the next, despite them having the said constant mesh box design in all of them. Also some had clutch brakes and some didn’t in the early years, the clutch brake basically allows the engine and gearbox to reach a matching revolution speed to allow smooth gear change or meshing of the clutches in the box when selected, the actual gears are as the name suggests meshed constantly whereas the true crash boxes had the straight toothed gears separate and they had to be engaged, with some deftness it has to be said, to the next gear by the driver to achieve a quiet and smooth change, its doubtful if you could change a crash box without the clutch as you could with the constant mesh just by allowing the revs to drop to the required speed.
My Father first taught me this on his Seddon, Gardner 150/ David Brown 6 speed box (constant mesh), being a young lad then I always thought the clutch was needed for a gear change. He did drive true crash boxes in the army and I think those that did any military driving had a good basis of learning and experience gained compared to their civilian counterparts, due to the varied types of vehicle and drive systems they had, some of which were quite crude, It was many of these ex servicemen who became the trunkers and trampers of the Fifties/Sixties and probably without them being aware the heavy motor industry had changed over to constant mesh boxes on the civilian commercial market but they still did their driving and gearchanging as before so to them they were still using crash boxes and so it went on until the 70’s/80’s even when drivers thought they were driving crash boxes because a ‘double de-clutch’ was the correct way to change and this would be passed onto newer drivers. Only my interpretation of course and in the end not a great problem but still many drivers will defend the statement ‘I drove a crash box’ when infact it would have been the much maligned constant mesh. Cheers Franky.
Hi Franky was the Scammell gate change a proper crash box ?
Frankydobo:
Sammy gave a good answer to your question Tony, I can only add we have to take into account many variations such as different engines, drive lines etc as to why gear changing can differ so much from one make of vehicle to the next, despite them having the said constant mesh box design in all of them. Also some had clutch brakes and some didn’t in the early years, the clutch brake basically allows the engine and gearbox to reach a matching revolution speed to allow smooth gear change or meshing of the clutches in the box when selected, the actual gears are as the name suggests meshed constantly whereas the true crash boxes had the straight toothed gears separate and they had to be engaged, with some deftness it has to be said, to the next gear by the driver to achieve a quiet and smooth change, its doubtful if you could change a crash box without the clutch as you could with the constant mesh just by allowing the revs to drop to the required speed.My Father first taught me this on his Seddon, Gardner 150/ David Brown 6 speed box (constant mesh), being a young lad then I always thought the clutch was needed for a gear change. He did drive true crash boxes in the army and I think those that did any military driving had a good basis of learning and experience gained compared to their civilian counterparts, due to the varied types of vehicle and drive systems they had, some of which were quite crude, It was many of these ex servicemen who became the trunkers and trampers of the Fifties/Sixties and probably without them being aware the heavy motor industry had changed over to constant mesh boxes on the civilian commercial market but they still did their driving and gearchanging as before so to them they were still using crash boxes and so it went on until the 70’s/80’s even when drivers thought they were driving crash boxes because a ‘double de-clutch’ was the correct way to change and this would be passed onto newer drivers. Only my interpretation of course and in the end not a great problem but still many drivers will defend the statement ‘I drove a crash box’ when infact it would have been the much maligned constant mesh. Cheers Franky.
Thanks Johnie & Franky ,
I think i understand now 
My father- like yours Franky would have learn’t on proper ‘crash’ boxes as he drove all varieties of lorries during the war, so it became natural to them to change gear that way as i don’t remember hearing him ever crunching the gears
Incidentally ,
has anyone got any interior pics?
Hi Franky was the Scammell gate change a proper crash box ? Fraid not mate Constant mesh too, it really was a design from way back, while putting up these posts I remembered I had an old Comm Motor from the Sixties, I dug it out earlier (looking a bit worse for wear now) and it has a list of the Tractive units obtainable in Britain, in the index for abbreviations it lists C for Crash, CM for Constant Mesh and A for Automatic along with others for Air Operated, Epicyclic, Synchromesh etc, not one vehicle listed has a C under the gearbox heading, I thought I’d at least find one. So we could say if you started your driving career after the Fifties then there was very little chance any of the vehicles driven had the old crash box unless you were unlucky enough to have an ancient ex war dept truck. I have to say I’m not an expert on the crash box and someone might correct me if I say I doubt they would come with more than four forward gears as it would usually be routed through a transfere or auxiliary box to gane further ratios as indeed the early constant mesh boxes were. In the Twenties/Thirties when crash boxes were common the trucks of the day didn’t need 6 speed boxes for the weight and speed limits then imposed. Anyway lets get back to the Mandator which I always thought was an unusual name and having been an AEC apprentice fitter I’ve always had a soft spot for the Ergo cabbed mark and the Mandator as it was the top motor along with the Mammoth Minor another favourite. Franky.
tonyhogi:
Incidentally ,
has anyone got any interior pics?
the truck did,nt have a interior yet alone any of us. the drivers seat was on a pedistool that did go up and down with a winder not air
the steering coloum was just a round tube with the wheel perched ontop. there was a rectangular box about a foot below the steering wheel
with the speedo and a couple of guages on .the fuel guage was on the diesel tank out side. a stalk was fastened on the steering coloum with the
indicator dip switch and horn on . the bonnet was a round topped thing made of glass fibre and you opened this to check and fill the oil.
and on extreem occasions rebuild engines this was done mainly by doing a head stand as the cab did,nt tilt. at the side of the seat was a large
cast ally box with the lights and heater switches on OH and a switch for the ignition you didnt have a key in the 60s just a flick switch and
a button nr the speedo. there was no head lineing or padding anywhere… then last but not least at the bottom of the drivers windscreen
a slot the looked like a demister for the windscreen when the air pressure dropped a pointer would raise up through a quarter of a circle
that was red in colour and said STOP reading top to bottom. when this poped up it was to late you could,nt stop as spring lock brakes was not fitted
to AEC s at this time. there is a photo on TN somewhere of a MK5 aec dash as it showed a aec with a techo and later without but it was maybe 8
months ago… in some peoples eyes (mine for one ) the mk5 high speed tractor was a special truck. not a F88 but quite a motor in its day.
capeable of 70 mph plus on motorways in the 60s.
good old days
john
Spot on with the MK5 description John,great wagons.I had a MK5 MM 526 GYG ex Cawoods Fuel Oils with the 2AV690 and 6-speed box complete with the CAV rotary fuel pump and it was a flyer.I used to take the door handle off when I parked up as anybody could undo two screws and turn the handle to get in .If you knocked the ignition switch up on the dash the mileometer and speedo stopped working,ideal for running a bit errrrrrrrrr well should I say slightly off route? I think I’m right in saying that the last MK5s had the 2AV691 engine fitted same as the early tilt cab Mandators,superseded by the AV760.
Hiya chris… have you no mk 5 interior photos. the adams did have 691s in them, towards the end i think one had a 760 sliped in
after a ergo whent ploughing on the A52. little story !!! the phone rang one night and the driver (Reg tea time trunk to london mamoth minor)
was coming back through Derby towards Ashbourne and the radator burst, so the garage lads grabbed a rad some hoses and off they went
as they got to the area where the waggon was,The police was all over the place. after a small search the garage lads found a trailer on its side
with the turntable still on the pin and the truck in 5 large pieces scattered around the field. the drivers last memories after banging
his head was a hissing of steam, so after coming round found a AA box and said he required a radiator. The lads looked right idiots turning
up in a transit when they really needed a host of recovery trucks and a flat to put the bits onto.Reg recovered and lived on another 10 years trunking.
John
they were compleate crap compaired to a scania you could at the same time I no iam a expert
rayluv:
they were compleate crap compaired to a scania you could at the same time I no iam a expert
by the time Scania arrived the mark 5s had 750 000 miles.on the clock.
John
3300John:
Hiya chris… have you no mk 5 interior photos. the adams did have 691s in them, towards the end i think one had a 760 sliped in
after a ergo whent ploughing on the A52. little story !!! the phone rang one night and the driver (Reg tea time trunk to london mamoth minor)
was coming back through Derby towards Ashbourne and the radator burst, so the garage lads grabbed a rad some hoses and off they went
as they got to the area where the waggon was,The police was all over the place. after a small search the garage lads found a trailer on its side
with the turntable still on the pin and the truck in 5 large pieces scattered around the field. the drivers last memories after banging
his head was a hissing of steam, so after coming round found a AA box and said he required a radiator. The lads looked right idiots turning
up in a transit when they really needed a host of recovery trucks and a flat to put the bits onto.Reg recovered and lived on another 10 years trunking.
John
Wish I had some MK5 interior photos John. 
Nice little story about the radiator.
This one had the 691 engine John,EWX 752C fleet 194,shown here in a dilapidated state at our Sheffield depot.IIRC she was ex Harold Wood and the regular driver was Bill Bullock. I was fortunate enough to have hold of this motor once or twice whilst he was on holiday as I had no regular wagon at the time.Bill kept it immaculate inside and out and it was a cracking motor.It was one of the few MK5s we had that were uprated to 26t GVW around 1970.
Photo courtesy of Tony Griffin.
Here’s a photo from our Barking depot.
The first one was ex Shell Mex and BP and the next two with the Yorks West Riding regs were ex Harold Wood.
3300John:
rayluv:
they were compleate crap compaired to a scania you could at the same time I no iam a expertby the time Scania arrived the mark 5s had 750 000 miles.on the clock.
John
I was going to say the same John as the ergo cab Mandator was out before the Scania’s were sold over here.
Johnnie
rayluv:
they were compleate crap compaired to a scania you could at the same time I no iam a expert
I don’t understand that sentence Ray .
Chris Webb:
rayluv:
they were compleate crap compaired to a scania you could at the same time I no iam a expertI don’t understand that sentence Ray
It’s OK Chris, nobody else does either - the bloke’s living on the planet Zanussi. I’ll fill you in about it later 