changing 5th gear set

[pumad]

Hi there,

Since i'm somewhat annoyed by the high revs my Puma makes on the motorway i did a little bit of research on the ib5 gearbox. This showed my that the 5th gear of a Puma is geared 0.88, and on the normal fiesta's and focus's is 0.76. in combination with my own gearbox, those set of gears will drop the RPM at 120 kmph, from 3700 to 3050. A lot more comfortable for a bit of highway cruising.

it should be possible to switch it over if i buy a focus of fiesta box... but does some of you tried this already, and is this possible without taking the box of the car?

greetz

 

[ElDude at Allison Automotive]

Hi there,


it should be possible to switch it over if i buy a focus of fiesta box... but does some of you tried this already, and is this possible without taking the box of the car?

greetz

Not impossible probably.. but fiddly!.. plus, you'll need the 5th gear puller..

sometimes a basic puller can pull the older ones off, but they can be VERY tight needing the proper SPX tools one which is 100 notes..



Chris

 

[pumad]

a bit of fiddling is beter then taking the box apart! I will be doing it at a Ford garage so i think they should have the puller.... hopefully.. then its on looking for a cheap box! thanx

 

[jacko]

should be do-able...

check out my gearbox / changing clutch guide in the how to section. thats with gearbox out of car....but should be able to undo gearbox mounts and just lower it a little to clear the chassis rail

 

[pumad]

Yes that were my thoughts to! Undoing the gearbox mount on the car will cause the engine included the gearbox to tilt... and should be able to give enough space.... theoretically :lol:

first i have to find a IB5 transmission from a Fiesta mk4, mk5 or a focus mk1/2 1.6/1.8!

 

[oilburner]

If you get a Focus gearbox you'll need to put the Puma gear linkage on as the Focus has a cable operated gear shift

 

[jacko]

i think he just wants it for the 5th gears...not the whole box

 

[pumad]

yep, just changing the 5th gear... so if you know anyone with a broken gearbox!

 

[PumaNoob]

Ive done the exact same operation you describe, but i put a 5th gear in that was too tall, and just dropped the mount off the top and rear of the gearbox, and took the 5th gear off and replaced it with a ST150 5th. Its really quite easy, but as said above, i tried a few different 3 legged pullers with no sucess, so i had to buy a proper IB5 5th gear puller.

Just a note, i know you probably already know, but you need to take final drive ratios into consideration when selecting gears to use, because crown and pinion gears are different ratios, so it might be a good ratio in a focus, but when you fit it to a puma box, they can be higher revving then the puma! Best thing to do is count the teeth. I have 1.4 fiesta 5th gears, fiesta ST150 5th gear, and a focus 1.6 5th gear if you need any main and layshaft teeth counts.

 

[pumad]

Just picked up a gearbox from a fiesta 1.25. I've done the math of the ratio's and this one have to do it perfectly.

It offcourse will have a bigger gap from 4th to 5th.

But the Fiesta ST150 has a 0.88 ratio on 5th isn't it ?

 

[PumaNoob]

I cant remember the exact ratios, but it was a lot better for me. With a turbo, you need to be able to get to them high revs pretty quick, but with the 1.4 gear, it took about an hour to get into boost :lol:

 

[pumad]

I cant remember the exact ratios, but it was a lot better for me. With a turbo, you need to be able to get to them high revs pretty quick, but with the 1.4 gear, it took about an hour to get into boost :lol:

:lol: yeah, would love to have that problem! haha! But with the ratio you have now, whats your topspeed?

Since i live 2 km of the german border i regularly drive on the autobahn, then is a bit longer gearing not a luxury but a need

 

[PumaNoob]

With the ST150 gear, it was about 150mph at 7000rpm. But i broke that gearbox so i have a different set up now!

 

[corley]

lol you killed it? what gearbox are you using now? is it true that the differentials in the ST150 box are quite weak and when they go they tend to destroy the box?

 

[PumaNoob]

I wouldn't know about the ST diffs, that's the 1st thing I changed, for a Tran-x LSD. All I know is the bearings are supposed to be stronger in the ST box, but this is just from what I've read on forums.

Now I'm using another hybrid gearbox. It's a Mondeo mk3/focus mk2 casing (the only other ford box that will bolt to my engine), and internals are a mixture of focus RS internals and mondeo internals. So far seems to work well.