MT75 g/box
22-01-2013, 12:19 AM
#1
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MT75 g/box
hi chaps..
im slowly but surely getting a black 2wd saph sorted with a cossie bob lump.
but of course i cant use my standard 2dohc MT... it wont fit the block.
SO... i was wondering if anyone knows how long the main input shaft should be on my "newish g/box" in order to mate with the v6 block.
a comparison of measurements would be really helpful as i havent as yet ripped my saph to bits, its just sitting there without a battery waiting for a sicko heart transplant.
i've also heard that theres shafts with 25 and 26 teeth on the spline. im not so sure which one i need.
i'll obviously need to know what to look out for when getting one.
i'm set on the MT75 as it will probably not break on me... its gotta be reliable for every day use with the odd blatt!
Many thanks
im slowly but surely getting a black 2wd saph sorted with a cossie bob lump.
but of course i cant use my standard 2dohc MT... it wont fit the block.
SO... i was wondering if anyone knows how long the main input shaft should be on my "newish g/box" in order to mate with the v6 block.
a comparison of measurements would be really helpful as i havent as yet ripped my saph to bits, its just sitting there without a battery waiting for a sicko heart transplant.
i've also heard that theres shafts with 25 and 26 teeth on the spline. im not so sure which one i need.
i'll obviously need to know what to look out for when getting one.
i'm set on the MT75 as it will probably not break on me... its gotta be reliable for every day use with the odd blatt!
Many thanks
22-01-2013, 12:40 AM
#2
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try here mate
http://www.fordpower.org.uk/forum2/
I recall Dojj from here suggesting to look there regarding the gearbox
http://www.fordpower.org.uk/forum2/
I recall Dojj from here suggesting to look there regarding the gearbox
22-01-2013, 04:30 PM
#4
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You need a v6 box from a 2.8 Granada or xr4x4/xr4i sierra(mt75 4x4 v6 box not cossie one) for the front housing and youbolt your box to the vack of it using v6 shaft as its longer making an mt75 hybrid
so i take an "xrV6" box, and take the bellhousing with outer casing off it.
then slide my dohc internals into it... is this right? (ive heard i need the longer v6 input shaft in place)
i bet its not a straightforward job though is it?!
i suppose it would be cheaper to do it myself in this way, but would it be worth paying for a ready built v6 mt75? i mean it might be a bloody mission resulting in superglue all over my cuts. not to mention to bother.
22-01-2013, 06:39 PM
#5
Not entirely sane
It's not very straightforward as you need special tools to get the casings apart. Basically what has been said is correct, bellhousing/front casing and input shaft from the V6 MT75 4x4 gearbox and the back end/internals from the DOHC or Diesel box. The Diesel box will give you a top gear ration of 0.75:1, the DOHC is 0.82:1.
23-01-2013, 02:19 PM
#6
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Useful stuff chaps - thanks
This diesel ratio setup... i take it all the gears are slightly taller due to a lesser revving engine? cos if it is, this sounds like an ideal box for me.
Then i could further stretch it out with a diesel diff, which is what i was considering as an option on its own, before.
Does anyone know roughly how fast the diesel sierras go in each gear? (then i could make a rough calculation on how fast mine'd go with more revs on tap)
cos i really would like a torquey speed cruiser that crosses counties with no effort.
Fuck the government* - im trying to make a car thats just as cheap to run and better performing and better on fuel than anything the showrooms can give me, and i dont have to feel so bad about putting 75-80quid in my tank - *bastards
rant over
This diesel ratio setup... i take it all the gears are slightly taller due to a lesser revving engine? cos if it is, this sounds like an ideal box for me.
Then i could further stretch it out with a diesel diff, which is what i was considering as an option on its own, before.
Does anyone know roughly how fast the diesel sierras go in each gear? (then i could make a rough calculation on how fast mine'd go with more revs on tap)
cos i really would like a torquey speed cruiser that crosses counties with no effort.
Fuck the government* - im trying to make a car thats just as cheap to run and better performing and better on fuel than anything the showrooms can give me, and i dont have to feel so bad about putting 75-80quid in my tank - *bastards
rant over
23-01-2013, 04:22 PM
#7
Useful stuff chaps - thanks
This diesel ratio setup... i take it all the gears are slightly taller due to a lesser revving engine? cos if it is, this sounds like an ideal box for me.
Then i could further stretch it out with a diesel diff, which is what i was considering as an option on its own, before.
Does anyone know roughly how fast the diesel sierras go in each gear? (then i could make a rough calculation on how fast mine'd go with more revs on tap)
cos i really would like a torquey speed cruiser that crosses counties with no effort.
Fuck the government* - im trying to make a car thats just as cheap to run and better performing and better on fuel than anything the showrooms can give me, and i dont have to feel so bad about putting 75-80quid in my tank - *bastards
rant over
This diesel ratio setup... i take it all the gears are slightly taller due to a lesser revving engine? cos if it is, this sounds like an ideal box for me.
Then i could further stretch it out with a diesel diff, which is what i was considering as an option on its own, before.
Does anyone know roughly how fast the diesel sierras go in each gear? (then i could make a rough calculation on how fast mine'd go with more revs on tap)
cos i really would like a torquey speed cruiser that crosses counties with no effort.
Fuck the government* - im trying to make a car thats just as cheap to run and better performing and better on fuel than anything the showrooms can give me, and i dont have to feel so bad about putting 75-80quid in my tank - *bastards
rant over
Wes
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23-01-2013, 05:28 PM
#9
been there done that as far back as 1999 and was the very first person to do it so this is what you need to do
you need to find a diseasal mt75 box from a diseasal ford scorpio (not a granada scorpio, a ford scoprio, the one with the ugly face)
you then need to find a 2wd mt75 gearbox from any dohc sierra
then you need a gearbox from an xr4x4 2.9, no other box will do, and it was, at a time, cheaper to buy a complete car as you will also need the flywheel, pedal box etc from it
bolting it together in a bit
you need to find a diseasal mt75 box from a diseasal ford scorpio (not a granada scorpio, a ford scoprio, the one with the ugly face)
you then need to find a 2wd mt75 gearbox from any dohc sierra
then you need a gearbox from an xr4x4 2.9, no other box will do, and it was, at a time, cheaper to buy a complete car as you will also need the flywheel, pedal box etc from it
bolting it together in a bit
23-01-2013, 06:43 PM
#11
there were 4 different ratchets in the pedal box, white, red, yellow and black and because it's been such a long time since i stopped fiddling with sierra's i can't be sure what colour is the correct one for the clutch that you need to use
it all depends on which pressure plate and friction plate you use, i'd recommened the large turbo escos one but then you have to ensure you have the correct release bearing to go with it, some are plastic and some are metal
back to the box though
you need to break down all 3 boxes and use the rear casing and gear selector from the dohc, insert the diesasal countershaft and 5th output shaft into this and use the input shaft and front casing from the xr version with the v6 bellhousing pattern
this is also where things get confusing because you need to use the flywheel AND FLYWHEEL BOLTS from the manual engine (you may need to buy new bolts if you can get them and you have to put threadlock on them, the auto ones have smaller heads, 16mm i think as opposed to the 17mm ones for the manual box, but more importantly they are longer) but more importantly there are several different starter motors, some with 8 teeth and some with 9 and some with 2 bolts and some with 3
DO NOT USE the 2.0 dohc starter as they ONLY fit the dohc 4wd engine/gearbox/flywheel as the gear is offset but as they will only fit the dohc 4wd it may be worth keeping as you can recon them
once you have bolted everything back together you will be able to fit a 2wd mt75 gearbox to your 24V engine AND use the 0.75:1 5th gear to replace the standard 0.83:1 5th which should be good for around 30mph/1000 rpm which, when i did it, had my speedo going way off the clock with revs still left to go (before i blew it up
)
i think i had 8 or 9 boxes in my time, one lasted a whole 23 miles before it went kaput so what i would advise is to make sure you are able to drop the lump and box in one go as it's much easier to remove it that way that fiddle about trying to put 15 foot worth of extension on to get some some of the bolts at the top
it all depends on which pressure plate and friction plate you use, i'd recommened the large turbo escos one but then you have to ensure you have the correct release bearing to go with it, some are plastic and some are metal
back to the box though
you need to break down all 3 boxes and use the rear casing and gear selector from the dohc, insert the diesasal countershaft and 5th output shaft into this and use the input shaft and front casing from the xr version with the v6 bellhousing pattern
this is also where things get confusing because you need to use the flywheel AND FLYWHEEL BOLTS from the manual engine (you may need to buy new bolts if you can get them and you have to put threadlock on them, the auto ones have smaller heads, 16mm i think as opposed to the 17mm ones for the manual box, but more importantly they are longer) but more importantly there are several different starter motors, some with 8 teeth and some with 9 and some with 2 bolts and some with 3
DO NOT USE the 2.0 dohc starter as they ONLY fit the dohc 4wd engine/gearbox/flywheel as the gear is offset but as they will only fit the dohc 4wd it may be worth keeping as you can recon them
once you have bolted everything back together you will be able to fit a 2wd mt75 gearbox to your 24V engine AND use the 0.75:1 5th gear to replace the standard 0.83:1 5th which should be good for around 30mph/1000 rpm which, when i did it, had my speedo going way off the clock with revs still left to go (before i blew it up
)i think i had 8 or 9 boxes in my time, one lasted a whole 23 miles before it went kaput so what i would advise is to make sure you are able to drop the lump and box in one go as it's much easier to remove it that way that fiddle about trying to put 15 foot worth of extension on to get some some of the bolts at the top
23-01-2013, 06:58 PM
#13
dojj
I have a 2.8 v6 flywheel(cos its much lighter) and been told how to adapt box/fork for full movement. I have XR4i engine cradle with Xr4i engine arms and a mt75 2wd gearbox cradle. What engine mounts do I need? as for clocks mine are cossie clocks with v6 rev counter!
Cheers wes
I have a 2.8 v6 flywheel(cos its much lighter) and been told how to adapt box/fork for full movement. I have XR4i engine cradle with Xr4i engine arms and a mt75 2wd gearbox cradle. What engine mounts do I need? as for clocks mine are cossie clocks with v6 rev counter!
Cheers wes
23-01-2013, 07:01 PM
#15
dojj
I have a 2.8 v6 flywheel(cos its much lighter) and been told how to adapt box/fork for full movement. I have XR4i engine cradle with Xr4i engine arms and a mt75 2wd gearbox cradle. What engine mounts do I need? as for clocks mine are cossie clocks with v6 rev counter!
Cheers wes
I have a 2.8 v6 flywheel(cos its much lighter) and been told how to adapt box/fork for full movement. I have XR4i engine cradle with Xr4i engine arms and a mt75 2wd gearbox cradle. What engine mounts do I need? as for clocks mine are cossie clocks with v6 rev counter!
Cheers wes
the 2wd v6 arms will fit the 2wd cradle with normal 2wd mounts but the mt75 needs it's own mt75 mount so you have everytihng you need
23-01-2013, 07:02 PM
#16
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DOJJ - i may have spoken to you at a ford show.
i went to a classic ford event at battlesbridge with my mate scott a few years back and met a couple a people on the classic xr stand... there was a black xr4 with a 3litre 12v in it and he told us how he'd worked on it and replaced 5th gear like we're talking about... and i thought to myself, why the hell is there not more people doing this? ... and both myself and scott agreed it was a good idea.
We walked away with an inspired grin on our faces.
i went to a classic ford event at battlesbridge with my mate scott a few years back and met a couple a people on the classic xr stand... there was a black xr4 with a 3litre 12v in it and he told us how he'd worked on it and replaced 5th gear like we're talking about... and i thought to myself, why the hell is there not more people doing this? ... and both myself and scott agreed it was a good idea.
We walked away with an inspired grin on our faces.
23-01-2013, 07:07 PM
#17
the 2.8 will work and it will rev up much faster, but you have to chop and reweld the fork at some point to give it full pedal travel or else it falls off the end of the pivot
the 2wd v6 arms will fit the 2wd cradle with normal 2wd mounts but the mt75 needs it's own mt75 mount so you have everytihng you need
the 2wd v6 arms will fit the 2wd cradle with normal 2wd mounts but the mt75 needs it's own mt75 mount so you have everytihng you need
Wes
Last edited by doga-ot; 23-01-2013 at 07:14 PM.
23-01-2013, 07:15 PM
#18
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This site has been a godsend to me and i cant help but come back to it time and again cos you guys are so helpful.
I believe that in the long run i will have saved a lot of stress... blood... and money... just by asking.
Big up all'a you's that know loads a stuff - its a shame your not paid for consultation.
I believe that in the long run i will have saved a lot of stress... blood... and money... just by asking.
Big up all'a you's that know loads a stuff - its a shame your not paid for consultation.
23-01-2013, 07:18 PM
#20
This site has been a godsend to me and i cant help but come back to it time and again cos you guys are so helpful.
I believe that in the long run i will have saved a lot of stress... blood... and money... just by asking.
Big up all'a you's that know loads a stuff - its a shame your not paid for consultation.
I believe that in the long run i will have saved a lot of stress... blood... and money... just by asking.
Big up all'a you's that know loads a stuff - its a shame your not paid for consultation.
23-01-2013, 07:47 PM
#24
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doga-ot -
i rather stupidly tried to go sideways round this rather tight corner in the snow.
it sounds more stupid than it really was but, long-story-short, i hit the curb and both rear wheels looked just like your photo and it made the car crab ever so slightly!
i corrected the crab with the tracking temporarily but found in the end that it was the diff mount. not so good.
--CARBODY--
I I
\ \
I I
I --DIFF-- I
patience and muscle with the diff lowered, a blowtorch and a very big adjustable spanner closed up over the mount straightened it out. YeeHaa! but its still fine today, a few years later.
i rather stupidly tried to go sideways round this rather tight corner in the snow.
it sounds more stupid than it really was but, long-story-short, i hit the curb and both rear wheels looked just like your photo and it made the car crab ever so slightly!
i corrected the crab with the tracking temporarily but found in the end that it was the diff mount. not so good.
--CARBODY--
I I
\ \
I I
I --DIFF-- I
patience and muscle with the diff lowered, a blowtorch and a very big adjustable spanner closed up over the mount straightened it out. YeeHaa! but its still fine today, a few years later.
23-01-2013, 08:09 PM
#27
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not bad not too far away then! Need to start meeting up with local people
Have you sorted a engine/gearbox cardale for yours and engine arms?
i've already bought the BOB lump and stripped it down... lightened and balanced crank and con rods so far, one piston broke on removal... so... lets get it bored out shall we? 3litre here we come with oversize pinto forged jobbies... havent done that yet (rebore and pistons). got the arms with the engine complete with auto gearbox and loom for - get this - 50rubs - nothing wrong with the engine itself.
so the money i save in buying it can go into performance (and then some)
all the cossie management and stuff is scrap to me although the loom was burnt to shit.
i want 3 carbs with a scoop and maybe NOS too if its all running well.
i cant help thinking this is all a million miles away but this whole gearbox thing has given me a kick up the back end and ive got the money to get the block sorted.
im getting itchy trigger fingers just finkin abou it!
23-01-2013, 08:16 PM
#28
Not entirely sane
It's only the 5th gear which is different on the Diesel box, the rest are the same. Not sure if you can still get them but you used to be able to buy the Diesel 5th gear for the mainshaft and a complete Diesel layshaft from Ford. It is possible to press the 5th gear wheel off the layshaft and replace it with the Diesel one but by all accounts you need a pretty beefy press to do it.
I got T boned in my XR4x4 back in 2010, the nearside rear wheel ended up with a funny toe in angle. Looking underneath, you couldn't see anything bent apart from the ARB drop link on that side. For complete peace of mind, I replaced both semi-trailling arms, the beam, diff mount and drop links. It's fine now.
I got T boned in my XR4x4 back in 2010, the nearside rear wheel ended up with a funny toe in angle. Looking underneath, you couldn't see anything bent apart from the ARB drop link on that side. For complete peace of mind, I replaced both semi-trailling arms, the beam, diff mount and drop links. It's fine now.
23-01-2013, 08:24 PM
#29
cool bud same as me BOB is a cunt becuse so much electrics to over come thats why I went BOA, if you dont need ECU sell it to janspeed! I use my saph so when I have everything hopefully in next few weeks will try get it done over a weekend or the week at the most! if you have BOB arms they are no good for the sierra
23-01-2013, 08:31 PM
#30
It's only the 5th gear which is different on the Diesel box, the rest are the same. Not sure if you can still get them but you used to be able to buy the Diesel 5th gear for the mainshaft and a complete Diesel layshaft from Ford. It is possible to press the 5th gear wheel off the layshaft and replace it with the Diesel one but by all accounts you need a pretty beefy press to do it.
I got T boned in my XR4x4 back in 2010, the nearside rear wheel ended up with a funny toe in angle. Looking underneath, you couldn't see anything bent apart from the ARB drop link on that side. For complete peace of mind, I replaced both semi-trailling arms, the beam, diff mount and drop links. It's fine now.
I got T boned in my XR4x4 back in 2010, the nearside rear wheel ended up with a funny toe in angle. Looking underneath, you couldn't see anything bent apart from the ARB drop link on that side. For complete peace of mind, I replaced both semi-trailling arms, the beam, diff mount and drop links. It's fine now.
23-01-2013, 08:35 PM
#31
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It's only the 5th gear which is different on the Diesel box, the rest are the same.
23-01-2013, 08:44 PM
#32
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so much electrics to over come thats why I went BOA
23-01-2013, 08:45 PM
#33
the 2.8 will work and it will rev up much faster, but you have to chop and reweld the fork at some point to give it full pedal travel or else it falls off the end of the pivot
the 2wd v6 arms will fit the 2wd cradle with normal 2wd mounts but the mt75 needs it's own mt75 mount so you have everytihng you need
the 2wd v6 arms will fit the 2wd cradle with normal 2wd mounts but the mt75 needs it's own mt75 mount so you have everytihng you need
23-01-2013, 08:47 PM
#34
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if you have BOB arms they are no good for the sierra
spose i'll have to buy these too - BOA ones ok? or xr ones? i dont know
23-01-2013, 08:50 PM
#36
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Only the pivot point needs changing not the arm, well worth the effort the 2.9 one is way heavier
23-01-2013, 08:56 PM
#40
I knew it was something about the pivot ade but it's been probably 6 years since I was explained the ins and outs of what went where and what fell off 
That bent wheel looks like its potentially the arm but they also have a habit of bending the rear beam point up points as they aren't that tough when they get clouted so there are some things to check
That bent wheel looks like its potentially the arm but they also have a habit of bending the rear beam point up points as they aren't that tough when they get clouted so there are some things to check