changing diff ratio's

[BigMav]

Whats involved in changing diff ratio's from 3.9 to say 4.1 in my mav. Would it be better to get 4.3's or 4.6's? I'm running a 33" tyre and will probably stay with that size but may go for 35's some time down the track. Is the difference between 3.9 and 4.1 really noticeable? What sort of costs would i be looking at if doing this mod?

[bogged]

Whats involved in changing diff ratio's from 3.9 to say 4.1 in my mav. Would it be better to get 4.3's or 4.6's? I'm running a 33" tyre and will probably stay with that size but may go for 35's some time down the track. Is the difference between 3.9 and 4.1 really noticeable? What sort of costs would i be looking at if doing this mod?

I had quotes ranging from $500 - $1100 to change ratios in 2 diffs.


Which motor do you have??

If I remember correctly, God, alias Bazzle said it changes 300rpm per ratio in a TD42 diesel.

eg
3.9 -> 100kph - 2000rpm
4.1 -> 100kph - 2300rpm
4.3 -> 100kph - 2600rpm
4.6 -> 100kph - 2900rpm


So bit of difference.

I thought the same, I have 4.1, and want 4.3 as 4.6 would suck for long road trips at 110kph.

[BigMav]

thanks for the info bogged, i have the td42 with a turbo. 4.1 or 4.3 does sound like the go, it really cruises well at the moment at 110 with 3.9's, i think 4.6's maybe a bit extreme. Were those prices you mentioned for second hand gear sets or new and are they difficult to fit yourself? This is all probably simple stuff thats been asked a million times but i just don't know jack about diffs. sorry.

[BigMav]

If i wanted to keep my highway economy would i be correct in saying i can fit a rockhopper or marks gearset to the transfer case that will only affect low range four wheel drive. I could always get some 4.1 diffs to help a little bit on the highway and the rockhopper for when i really need it in low range.

[bogged]

Were those prices you mentioned for second hand gear sets or new

They were just FITTING... Not supply.

4.3's rare as Mozzie poo, and about $1000 per end Nissan... I looked at a set, got all excited, but they had a dodgey wear pattern on them, so would have suffered from diff whine.

4.1 pretty common and have seen numerous here.

Fitting yourself - NFI.

Rockhoppers yes, affect low only

[TUFFRANGIE]

fitting the new ratio's to the front is pretty easy, just pull out axles a bit, drain diff oil, undo prop shaft and undo the centre, remove and install new ratio's, fill back up with oil and grease wheel bearing while you are at it.

The back I haven't tried but going by what i have heard about rear wheel bearings it would be a fair bit harder

I picked up a front centre 4.1 ratio for $150 bucks

[bazzle]

Rear easy too.Drain oil
Unbolt calipers, hang to one side
Undo bolts holding axle in
Pull axles and bearing holders out.
Undo prop
Undo diff bolts
Remove 3rd member
swap in 4.1 centre.


Reverse
Add oil

Bazzle

[XterraGuy]

Hmm, I've got a 4.363 open third with zero miles, a 4.636 LSD third with 90K miles, and another 4.636 LSD third with fewer miles soon to come. All 33-spline H233B. Wonder if any of you folks would be interested in 'em, either complete (shipping would hurt at 90 lbs.) or just the R&Ps? The US-spec LSDs are pretty useless, but can be tuned up.

Brent

[bogged]

Hmm, I've got a 4.363 open third with zero miles, a 4.636 LSD third with 90K miles, and another 4.636 LSD third with fewer miles soon to come. All 33-spline H233B. Wonder if any of you folks would be interested in 'em, either complete (shipping would hurt at 90 lbs.) or just the R&Ps? The US-spec LSDs are pretty useless, but can be tuned up.

Brent

Work out for R&P to melbourne.. scare me.

[bazzle]

Back to the question BigMav

4.1s are a good compromise for 33's.
Shop around for complete drop in centres. May be cheaper than ring and pinions, and easier to change

Bazzle

[BigMav]

Thanks for the tips. Its not something i will be doing right away as there are other things that need sorting out first but it is on the list.
Cheers

[XterraGuy]

Hmm, I've got a 4.363 open third with zero miles, a 4.636 LSD third with 90K miles, and another 4.636 LSD third with fewer miles soon to come.

Work out for R&P to melbourne.. scare me.

Well, FedEx and UPS quotes are only for ~1 week or less arrival and are definitely scary (~$200 US +/- $25). But, surface parcel post via the USPS in 4-6 weeks to Melbourne 3000 is $41 US. That's for one R&P which is listed at 8240 grams in the parts system, figure a 40x40x30 cm package. A pair of 'em comes in at ~$70 US.

Just for yuks I estimated how much a 40 Kg third member would cost. USPS won't ship it. FedEx/UPS run in the neighborhood of $500 US, ouch!

Brent

[RMP&O]

you can always use DHL or any sea frieght company such as Wilson Logistics. Takes a long time but is way cheaper than by air. I have got quotes from UPS for near $1000 USd to ship heavy parts by air to S.America. It is a joke what they charge for air freight and the worst part is they have different rates depending on your location. Meaning to ship in reverse is way cheaper, I got a quote from S.America to me for 1/10th what it was from me to S.America!! I got a complete turbo with manifolds from new Zealand for about $200 by air and DHL was used. Shipping lift kits complete with new springs from Aus has ran me $200-400 with customs fees and that bs added in...by sea of course.

[XterraGuy]

Bah, DHL only offers air express at ~$200 for one estimated R&P package.

[RMP&O]

I think you could say that is an example of it being more from you to them than from them to you. If you called any place in the USA or used a USA website you will get the USA price quote. Regardless it is more expensive to export than to import because of this!! unless you use sea freight. Then it seems the same...but I do not want to export anything only import what we never got!!

BTW, $200 is more than my turbo from New Zealnd and it was DHL in two large boxes, manifolds included.

[bogged]

Bah, DHL only offers air express at ~$200 for one estimated R&P package.

[XterraGuy]

What? If you want 'em under 2 weeks, that's what it costs. But again, I can send 'em via standard US Mail for MUCH cheaper, just might take a month or so.

Mind you, these are no good for your high-pinion front diff, but you could certainly save some cash on the rear if you're interested...

Brent

[XterraGuy]

And yes, 4.363 is perfectly OK to pair with 4.375, likewise 4.636 and 4.625, 4.90 and 4.88, etc. 1% difference is dandy, 2% is about the max you can run.

So if <$50 US to ship sounds good, PM me and we'll come up with a price.