Outer Limits 4x4 Board

ive got a gu auto running 35's, wanting to hear what people have run to best bring back to std on the speedo. Have had different oponions from different people

Depends on what the overall increased tyre diameter is for the 35's over stock - the diff ratio needs to be approximately the same increase over your current ratio to correct the speedo. Say for 20% higher overall diameter, your diff ratios need to be 20% higher to correct.

Otherwise, maybe there are speedo corrector kits out there, if your desired driving characteristics aren't met by the diff change (or cost is a concern)?

ads80 wrote:ive got a gu auto running 35's, wanting to hear what people have run to best bring back to std on the speedo. Have had different oponions from different people

what are your current diffs?

if they are 3.9 then go with 4.3's
4.1 go 4.6 etc

not so concerned about the speedo, just need to get it back to std so the auto will shift properly and the car will tow better, already have a speedo converter in the car but this caused problems the auto senses from both tailshaft and the speedo, so when you change one and not the other the auto gets a little confused

gu autos have 3.9, hoping to hear from someone who has done the change

ads80 wrote:gu autos have 3.9, hoping to hear from someone who has done the change

I have a Gu 4.2 TD and i run 35s all the time.
i fitted 4.3s to my truck, they were 3.9s originally. 4.3s are perfect!!!!

Grant.

ads80 wrote:gu autos have 3.9, hoping to hear from someone who has done the change

4.8s have 3.5's

What auto? I assume it isn't the 4 speed as in the GQ? If it is then I'd say talk to Wholesale Automatics and get a valve body for it!

As GUEEY Said

I also run 315/75's all the time and originally had 3.9's. I have bought the 4.3's to bring the ratio back to std for speedo correction and off the mark up hill starts. Sure - they're still sitting on the bench waiting to in with the lockers but hey they're there!

Will also be putting in a replacement 5th gear cog in the box to keep the advantages of bigger tyres (lower revs = better fuel economy) on 5th gear highway cruising in the future also.

benhl wrote:As GUEEY Said

I also run 315/75's all the time and originally had 3.9's. I have bought the 4.3's to bring the ratio back to std for speedo correction and off the mark up hill starts. Sure - they're still sitting on the bench waiting to in with the lockers but hey they're there!

Will also be putting in a replacement 5th gear cog in the box to keep the advantages of bigger tyres (lower revs = better fuel economy) on 5th gear highway cruising in the future also.

are you going to go with the Marks Adapters different ratio 5th gear??

i think so... i haven't really looked too far into it - just heard around the traps that it is the way to go,

benhl wrote:i think so... i haven't really looked too far into it - just heard around the traps that it is the way to go,

apparently the 5th gear is near on $800

diff ratio's are the best way to go i went from 4.1's to 4.65's and on 37's the car still drives like stock on the freeway --- have checked the speedo with a gps and its bang on .

same on 35's only runs about 120rpm more at 110k's

wouldn't mind knowing more about a new 5th gear if anyone has tryed it .
like all GU's its doing about 2500rpm at 110k's and not getting the best fuel consumption

truckzilla wrote:diff ratio's are the best way to go i went from 4.1's to 4.65's and on 37's the car still drives like stock on the freeway --- have checked the speedo with a gps and its bang on .

same on 35's only runs about 120rpm more at 110k's

wouldn't mind knowing more about a new 5th gear if anyone has tryed it .
like all GU's its doing about 2500rpm at 110k's and not getting the best fuel consumption

http://www.marks4wd.com/products/gearma ... -gears.htm