diff change

[hodgson4711]

hi, hope you can help. when i fitted my diesel engine into my 81 mk2 transit i didn't change the diff and, have since been told i should fit one out of a mk3 diesel. so far so good. my question is upto what year mk3 is it ok to use before they changed the diff. i hope you understand what i am trying to say. regards H

[Luke]

first off why do you want to change the diff petrol and diesels have the same diffs in it's not a necessity to change it

if you do - you need to know the ratio of the one you have or you might end up putting the same one back in

but in answer to the question up to about 1991 will fit (i'm pritty sure ) after 91 (mk4) i'm 100% certain wont fit

[Luke]

just a thought swb or lwb - i'm assuming its a swb

[FredTransit]

where you told to change the diff just cos you converted to diesel? Cos you don't need to if you don't want to.

[white van clan]

If you are happy with the speeds in each gear then leave it be, if not you need to work out which diff you have and decide weather you need a longer or shorter ratio

[hodgson4711]

hi thanks for all the advice. i went to the classic camper rally at the weekend and a member said that if i changed the diff from a mk3 diesel transit i would get better mph and a quiter engine as the diesel diff. had more teeth than the petrol model. he seemed to know what he was talking about thats why i asked the question on the forum to comfirm it. regards H

[white van clan]

Are you happy with the speeds it does in each gear, are the revs high when cruising at 65/70 mph

[hodgson4711]

yes the speeds in the gears seem ok but at 60/70 the engine revs seem high but the engine sounds very noisy but i don't know if that is caused by over reving or just a noisy engine. regards H

[FredTransit]

What gearbox have you got? If it's a four speed it would be easier for you to change to a 5 speed. When I say easier I mean it would be easier to find. It involves a bit of work cutting a new hole for the gearleaver in the floor and changing the prop) but it's worth it

[Luke]

hi thanks for all the advice. i went to the classic camper rally at the weekend and a member said that if i changed the diff from a mk3 diesel transit i would get better mph and a quiter engine as the diesel diff. had more teeth than the petrol model. he seemed to know what he was talking about thats why i asked the question on the forum to comfirm it. regards H

he half did you can get lower ratio diffs but is not a petrol /diesel thing

the Di's are noisy - proberbly thier biggest downside
try a bit of sound deadening 1st have a read of andyg's thread

[hodgson4711]

hi fred its already got an mt75 fitted. all it is is a friend told me that the diff on a diesel is a couple of teeth larger than the petrol version. if so i would probally get a better mpg and it would make the engine less noisy. i allready have a kit from noisekiller fitted but the quiter the better.

[FredTransit]

OK sound deadening it is then! As Luke said see AndyG's thread.

[FFP]

hi,

topic leaves a few questions for me, as its not 100% sure a mk3 diff wil fit a mk1 axle.

i'm also running lots of revs and now doing 4000 rpm in 4th and 3200rpm in o.d. when doing 60 mph (5.14 diff)
tdi engine runs 4250 rpm max, so thats about 75 mph in overdrive

i have a spare mk1 5.14 square rear axle and a mk3 4.11 axle in the garage

can i simply put he 4.11 mk3 diff in the mk1 axle without any trouble??
will the halfshaft splines etc. of the mk1 fit the 4.11 diff??

wat is actualy the difference between the mk1 and mk3 axle? only the position of the shock mounts monting of the springs or how wide it is??

until i get my round capri type axle sorted i'd like to use the square type axle with the 4.11 diff and see if i actualy need a 3. something axle

little of topic,
but the two dissabler swithes in the overdrive gearbox, is the lower one of the two for 4th or 3th gear?? ( hope its 4th) i cant use the top one as my startermotor is in the way, so i plugged that hole. Dont want to open the gearbox to find out with is with. also read the post with the warning when not using the swithes and acedently using it in reverse or first and second gear.

gr Marc