13 speed OD gearbox

180wannabe wrote:

I have an idea i read somewhere once that the 6613 is an updated version of the 613, i think something to do with differently cut gears, but again happy to be corrected.

Brett.

I think they were a Finer cut gears & had 2 teeth in contact at all Times & were a Lot Quieter than the earlier Boxes..
The bigger Series Boxes they went from Straight cut teeth to helical Cut Teeth. But can't remember When!! Possibly with the 12 Series.??...maybe..??

It's been a while since I've been inside something that Small or Old... So I may have it arse about.. But happy to be Corrected..

I reckon you are right 'seed, and those finer cut gears/2 tooth contact, upgraded their rating to 660 lbs/ft.

I see no point swapping from a 10 sp........unless youre working in a Chinese coal mine .........another point about the small boxes,is you cant swap the gears around to get a overdrive.......you be needing all six front gears and the shifter clutch ,which are /were sold only as a set.

Maurice, if it's the overdrive that you are particularly after, an RTO-609 will give you a faster overdrive than an RTO-610 or RTO-613, 0.74:1 compared with 0.80:1.

Brett.

As John K says if working in a chinese coal mine cant beat 18 to 1 in low as against 12 to 1 in a ten speed (from memory) and it is a v8 petrol As the old saying goes better to have em not need em, than to need em and not have em

Thanks Brett

if you are really keen on overdrives ,you can get the 913/9513 series with a double overdrive........the splitter is an overdrive,and add a overdrive in the main box,which is quite possible by just swapping the gears around ,then you may have a 50% OD...........the Mack quad boxes had double overdrive ,so why not.

The overdrive kit for the 610 is only a couple gears, the rest are repostioned. I have both and RT and RTO610. Got lucky with the RTO as it had a new kit in it, paid 500 and the kit was double that cost at that time.
Bit of info,
www.4btswaps.com/threads/fuller-trannys-...68/page-2#post-51947
Steve

The small box parts were always very expensive.......9 and 12 series stuff was cheap as dirt.