Hi,
Rebuilding my www.marcosmantula.com from scratch and are looking at the gearbox that came with it. I am putting in a bigger 5.0v8 and are trying to work out if it would be worthwhile adjusting the diff to give a better cruising speed.
For this i need to know the geatbox ratios and understand that the 5th gear depending on gearbox model was either a 0.833:1 or a 0.792:1.
The serial number of the box is 19A20557B, i have searched the www and can find no meaning of the "B" at the end and does the 19A tell me what car/year/model it was from originally and whether it was one of the stonger or weaker versions ?
Or alternatively can i by counting the cogs work out the ratios myself ?
Regards,
Martyn....
Another gearbox identification queery LT77
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with the gearbox stripped and the clusters in situe ie:the input shaft pointing sky ward
working from the top
input ............. layshaft
22 ............. 33 = 4th / pinion gear
27 ............. 29 = 3rd
32 ............. 23 = 2nd
reverse .............
31 ............. 14 = 1st
20 .............. 36 = 5th
and 5th gear below the plate
it has the same ratios as an SD1 V8 box
to calculate the ratio's ..first divide the pinion gear ie: 33 / 22 =1.5
then divide the input shaft by the layshaft and multiply by the 1.5 ..and thats the ratio
ie:
1st gear
31 divided by 14 = 2.21 then times the 1.5 you got earlier and the result is 3.32 which is right
thankyou to Ben Ashcroft for explaining to me ... it makes sense now
working from the top
input ............. layshaft
22 ............. 33 = 4th / pinion gear
27 ............. 29 = 3rd
32 ............. 23 = 2nd
reverse .............
31 ............. 14 = 1st
20 .............. 36 = 5th
and 5th gear below the plate
it has the same ratios as an SD1 V8 box
to calculate the ratio's ..first divide the pinion gear ie: 33 / 22 =1.5
then divide the input shaft by the layshaft and multiply by the 1.5 ..and thats the ratio
ie:
1st gear
31 divided by 14 = 2.21 then times the 1.5 you got earlier and the result is 3.32 which is right
thankyou to Ben Ashcroft for explaining to me ... it makes sense now
remember it's only a bodge if it DOSN'T worK
Hi,
Thanks for the prompt replies, it seems that my diff can be fitted with different final drives however as mine is already the 3.09 this is the lowest available in the Atlas ZF LSD type according to Fostek Engineering (unless anybody knows different) serial number 19A205576B SD1 SE/VP.
I will have a look at my gearbox over the next week to see if mine is the 0.77 or 0.833 5th gear, hoping its the 0.77 for a better cruising speed (and a few more MPG on the motorway),
Regards,
Martyn
www.marcosmantula.com
Thanks for the prompt replies, it seems that my diff can be fitted with different final drives however as mine is already the 3.09 this is the lowest available in the Atlas ZF LSD type according to Fostek Engineering (unless anybody knows different) serial number 19A205576B SD1 SE/VP.
I will have a look at my gearbox over the next week to see if mine is the 0.77 or 0.833 5th gear, hoping its the 0.77 for a better cruising speed (and a few more MPG on the motorway),
Regards,
Martyn
www.marcosmantula.com
