Technical Gearbox 5. gear ratio ??

[Lars58]

Hii all

Lars from Norway with trouble...

I have a 2003 2,8l q15 and i had to change gearbox about 3 weeks ago.
New box works well BUT it is from a q18 chassis..16 inches wheels..i have 15 inches .an very wrong ratio for me
when running on my camping trips..
Now when speeding at 96 km pr hr my rev is 3000 rpm....before about 2000 rpm...

My 5. gear is 53/31..i open and look..also my old box has same 53/31...
So Big question is which ratio to order?? i find on ebay 58x35 and others,

Any tips will be very well recieved here

 

[corcai]

Now when speeding at 96 km pr hr my rev is 3000 rpm....before about 2000 rpm...

The difference in circumference between 215/70/15 and 215/75/16 is only 6.4% so it couldn't be 1000rpm difference. There are a few speedo pinion with differnt number of teeth so your rpm may be off.

If your rim can take a 215/80/15 suv tyre the circumference will be only 0.5% smaller a neglible difference.

 

[Lars58]

Jepp but big question is that i need to change 5.gear setup...any help me please..
And need for new setup gear is my engine feels pooping out in free air when driving on highways...in 110 kmph..

 

[robin123]

i have a ducato 1.9TD and had to change the gearbox as the syncro's were worn out at 50,000miles, gearbox's for this ducato are rarer then hens teeth so i had to make one from many different parts. The gear train i used was from a 2.8D, i didn't think to check gear ratios but after three weeks to get parts and rebuild i installed and test drove it today, I didn't notice any different in gears just how nice it was to slip into gear without the grinding noise

 

[robin123]

P.S total cost for rebuild and fitting 600.00pounds

 

[corcai]

You're missing the point your old differential is 74/15, the new differential is 68/13. Changing the tyre to a larger diameter will save you from changing the differential.