Mines packed up, the poxy piece of shit


i have a spare gearbox from a DOHC 4x4 sierra

now from what i gather, they are both the same strength, same fitment etc etc, but i'm unsure if they are the same gear ratio's - i can live with the lower gears been closer together aslong as 4th and 5th are the same - i'm 99% sure that 4th is 1:1 on both boxes, but i'm unsure about 5th and the other cogs.


any advice please?

 

boxes were the same I think only the diff ratios were different

 

Cheers Ian - i suspect the same, but need to be 100% sure before i break my back and my garage roof again


Found this on the RSOC webby about the 4x4 cossie gearbox

Internal ratios:

1st, 3.62:1
2nd, 2.08:1
3rd, 1.36:1
4th, 1.00:1
5th, 0.83:1



Just need to confirm that they are the same as the 4x4 DOHC gearbox

 

My reference book is saying that Saph Cosworth 4x4 5th gear is 0.83.

 

Doug -


do you have a refernce book for the twincam tho?

 

i thought they wouldn't fit????


you could always use the SEARCH button

 

NO

But as a guess I would say that whatever the twin cam 5th gearbox ratio is, it wont be vastly different from the Saph.........

I.E. changing from the standard Saph Cossie 15" wheels to (for example) 17" would be a much bigger difference.

 

Steve - physically they do fit

its just the gear ratio's i want to know about


and its never been discussed on here recently neither

 

the box came out of a 4x4 dohc ghia so has had an extremely easy life 60k miles of not much abuse and has been sat in my garage ever since


just desperate for the gear ratio's as its a job for next weekend i think

 

If anybody has an owners manual OR Haynes manual for the Sierra twin cam, then the gearbox ratio info will be shown

I predict a new topic title:

"FAO any Sierra twin cam owners - please read"

 

i've got all the owners manuals for one of them and it aint listed


i used to have the technical manual for the DOHC 4x4 aswell - but can't find the fooker as that would of had the info in it

 

Graceland


do a search "DOHC and gearbox"

https://passionford.com/forum/viewto...t=dohc+gearbox

https://passionford.com/forum/viewto...t=dohc+gearbox



hope that helps dude

 

Nice one Spiky


Joined: 15 Jun 2004
Posts: 30
Location: midlands
Posted: Wed Sep 21, 2005 11:11 pm Post subject:

Dont know about the diffs mate but i put the gearbox from a 2.0 dohc 4x4 sierra in my escort cossie as a quick fix and couldnt tell the difference.
I was told the ratios were different but as i say i couldnt tell the difference

 

that'll do me

time to break my back and garage roof again