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Gearbox Identification HELP!
Posted: 23 Dec 2018, 19:04
by The Hairy Camper
Anyone have any idea what code this is? Previous owner had no idea as he bought it as spares. No bell housing so i think i pretty much just have this code to go by!
First letter looks like a "D" Second an "L" maybe?? Can't find a box with a DL code though.
Cheers!
Re: Gearbox Identification HELP!
Posted: 23 Dec 2018, 19:21
by Aidan
two letters before the rib, probably a ABD from 1984
check the number of teeth on the crown wheel probably 29, maybe 34
Re: Gearbox Identification HELP!
Posted: 23 Dec 2018, 19:27
by 937carrera
I think you are looking in the wrong place.
The format for a 4 speed is as follows, according to Bentley, page 56:
AA dd [gearbox web]mm Y, where AA is the gearbox code.
Your picture shows the gearbox web, 01 for January and 4 for 1984
The 5 speed is in a different location, same structure, but no web in the middle.
I found using a brass brush in an electric drill worked best to clean the case up, followed by an oily finger to highlight the number.
(Aidan the expert beat me to it

)
Re: Gearbox Identification HELP!
Posted: 23 Dec 2018, 19:49
by The Hairy Camper
Aidan wrote:two letters before the rib, probably a ABD from 1984
check the number of teeth on the crown wheel probably 29, maybe 34
Thanks for stopping in Aidan, can you see ABD in the picture? Or have i scrubbed the wrong spot?
I will have a count of the crown wheel teeth tomorrow.
Re: Gearbox Identification HELP!
Posted: 23 Dec 2018, 20:03
by The Hairy Camper
937carrera wrote:I think you are looking in the wrong place.
The format for a 4 speed is as follows, according to Bentley, page 56:
AA dd [gearbox web]mm Y, where AA is the gearbox code.
Your picture shows the gearbox web, 01 for January and 4 for 1984
The 5 speed is in a different location, same structure, but no web in the middle.
Hi carrera, i think you may be right about that being the date. It was where the code was on my old 5 speed, but this may indeed be a 4 speed??
This box seems to say 01 20 94.
Re: Gearbox Identification HELP!
Posted: 23 Dec 2018, 20:04
by Aidan
AB(rib)D12 03 4 that's 12 March 1984, the rib was deleted from the area that is stamped after 1984
Re: Gearbox Identification HELP!
Posted: 23 Dec 2018, 20:21
by The Hairy Camper
Aidan wrote:AB(rib)D12 03 4 that's 12 March 1984, the rib was deleted from the area that is stamped after 1984
What would we do without you Aidan
I'll count the crown wheel teeth and update the post tomorrow.
Cheers!
Re: Gearbox Identification HELP!
Posted: 24 Dec 2018, 18:44
by The Hairy Camper
34 teeth on the crown wheel. I also noticed the numbers 42 and 236 written on the crown wheel. Are these clues Aidan?
Cheers.
Re: Gearbox Identification HELP!
Posted: 25 Dec 2018, 08:17
by Aidan
34 tooth crown wheel 7 tooth pinion so box is 4.86 final drive so is a very early ABD, after 84 they have 29/6 crown and pinion sets 4.83 final drive
crown and pinion matched pair number 236 and pinion height is 63.42mm
Re: Gearbox Identification HELP!
Posted: 25 Dec 2018, 09:12
by The Hairy Camper
Merry Christmas Aidan. Thanks for replying today.
Turns out that it's not a suitable box for me then, but at least i know what i've got now

Re: Gearbox Identification HELP!
Posted: 25 Dec 2018, 16:46
by Aidan
but worth keeping in case you fit a 1Y or similar in future
Re: Gearbox Identification HELP!
Posted: 25 Dec 2018, 19:24
by The Hairy Camper
Thanks Aidan, I'm slowly fixing up a 1Y. I would need different gear linkage I believe, as mine is currently a 5 speed
Is this early ABD box better than a late one? Or not a lot of difference?
Re: Gearbox Identification HELP!
Posted: 02 Jan 2019, 13:44
by Aidan
Not a lot of difference, it should have the later 3rd and 4th gears in, but it's possible it has the earlier fine toothed ones like a DU as it's crossover period hence it has the 34/7 crown and pinion same as a DU. It will have the early synchrohub on 3rd 4th if it hasn't been replaced yet which 97/100 times is cracked/will crack. It could be argued the 34/7 crown and pinion set is superior to the 29/6 one as it is Klingenberg rather than Gleeson pattern and the extra teeth means that duty cycle is less for each tooth.
Re: Gearbox Identification HELP!
Posted: 03 Jan 2019, 00:14
by The Hairy Camper
Cheers Aidan, I'm not sure why i enjoy absorbing all this information...but i do
Except the part where you said i basically have a 97% chance that the "synchrohub" will be cracked or will crack
