Changing Diff Ratios

[Bushbasher74]

Hello All,

I am new to the forum and now a Jeep owner.

I have a 1999 TJ with 31" Muds, 2" OME lift, Snorkel, Extractors and sports Exhaust and Best of all a Rear ARB Air-Locker.

Looking for ideas on diff ratios to allow me to run 33's and still be reliable and economical to go touring, with regular off road jaunts.

To my knowledge it currently runs 3.07's and I think they are to tall to handle the 33's. I was thinking of 4.11's and how big a job it would be and if I need different carriers etc to fit them.

While apart I am thinking of fitting an ARB Front Locker to match the rear.

Long term plans include More Lift, SYE, Custom Front Winch Bar and a Custom Rear Bar Including Tyre and Jerry can Holders.

Any helpfull information would be greatly appreciated,

Cheers

[driftdave]

Hi Bush

Im no expert, but I did a search a while ago and no one else has replied yet...
your looking about $400 for the ratios each end. Plus fitting which is about $1000 up. Plus you may as well get the locker put in at the same time so im guessing about $1300 for that plus a little extra for fitting. Plus side is you already have the compressor. You may also need new carriers, not sure about that one.

Best do the SYE and rear shaft, when you go to 33s. You can get by for a little bit, but things will break eventually.

Pretty much everyone else on here know more then I do so let them correct me.

Cheers
Dave

[driftdave]

Oh its also not impossible to change your ratios yourself, but not recommended by anyone.

Cheers
Dave

[Bushbasher74]

Thanks Dave,

I going to be running 33" Tyres and I am looking for ratio recommendations and finding out what other guys are running(4.11's or 4.56's), to maintain the drivability of my Jeep when touring and going off road.

I am a Truck Mechanic by trade and have done diffs before so they wouldn't be a problem, but these days I am Driving Trucks therefore won't have the time to do the job myself so I will be looking for a Diff Shop in South-East QLD.

[krankieone]

auto or manual?
If 3 speed auto (TF 999) 3.73 (or 4.11 if you may go to 35's later)3.73 is a little deeper than stock on 33's 4.56 will rev too high without overdrive IMO.

I haven't done the maths on the other boxes

[Bushbasher74]

Originally Posted by krankieone

auto or manual?
If 3 speed auto (TF 999) 3.73 (or 4.11 if you may go to 35's later)3.73 is a little deeper than stock on 33's 4.56 will rev too high without overdrive IMO.

I haven't done the maths on the other boxes

Thanks ,

Mine Is 5spd manual so 4.11's sound like they might be the go, as it only has 3.07's at the moment and don't think I'll go any bigger than 33's.

[Born Again 4x4]

I have posed a simliar question in the past and with 4.56 ratios your revs sit a bit to high for my liking at 100kmh I have a six speed and some one said with 33" tyres and 4.56 ratios they sit around 2400rpm which is 500ish higher then standard gearing and standard tyres. So based on that I am going to go 4.10 ratios which is closer to standard gearing on 33's. Some will argue that 4.56 gives you better off road crawling speed, which it does but it is only like an 11% reduction on 33" which is bugger all in terms of crawling, not worth putting up with the revs singing on the highway and the added fuel usage of sitting at those revs especially if you want to sit over 100kmh too.

thats my 2 cents