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diff ratios and related things

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diff ratios and related things

Postby geeves » Sat Feb 28, 2015 12:51 pm

First question
Did ubs69 bighorns ever come out with 4.5 diffs?
Second question Which is easier to change a 4.5 front to 4.3 or a 4.3 rear to a 4.5 including a locker swap?
3rd question. can the spider gears from my 4.3 locked diff be used in the 4.5 that was in the bighorn when I bought it?
As you can guess Im not happy but I suppose its my own fault.
When I bought the bighorn I swapped the locker from the old truck without checking
First decent trip every time I took it out of 4wd it was bound up and wouldnt release until I reversed back a few metres. Just checked it at home and turning the front wheel 10 times gives 22.75 turns on the driveshaft and the rear 22.5 which is a ratio of 4.55 and 4.3. Checked the original rear diff and not only does it have 41 tooth crown wheel somthings been munching on the spider gear teeth Big bite marks all over them
Does anyone have a very good open 4.56 rear diff they dont want?
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Re: diff ratios and related things

Postby isuzurob » Sat Feb 28, 2015 12:58 pm

rear diff head is easier to change, but depends what ratio you want, i would try to keep the 4.5 if you are 4x4 still, spider gears can be swapped, i have a few sets if you get stuck from my locker swaps in my trucks, also have an open 4.5 rear out of a 2.8 mu somewhere if you get stuck, was going to use in the rear of my rodeo with a locker, never seen a bighorn with 4.5 factory as they were 3.1 with more torque so had higher ratio diffs
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Re: diff ratios and related things

Postby geeves » Sat Feb 28, 2015 1:52 pm

option code HC6 tells it all. you might not of seen a factory 3.1 with 4.5 diffs but you have seen a photo.
It would also explain why Foxton beach was such hard work.
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Re: diff ratios and related things

Postby isuzurob » Sat Feb 28, 2015 4:29 pm

4.3 and 4.5 would be fine on soft stuff, mates run 4.5 rear and 4.8 fronts in winch challenge safari and crusiers, just dont drive on grass and tarseal
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Re: diff ratios and related things

Postby geeves » Sun Mar 01, 2015 6:16 am

So Whangamomona and Aotuea in the dry Earnies place in a drought and maybe 100km on gravel in 4wd was not good for it? :o waitangi weekend saw 1000km on the car with over 300 not on normal roads
New something was wrong when dropping out of 4wd at gravel end onto seal and the front was defiantly travelling slower than the rear. Stopped to check things within 50m Untill the hubs unlocked it was undrivable on a hard surface
Now the spare diff I have is good except the spider gears. Are you sur the gears can swap from my 4.3? Is it a major or is it something they have to dismantle to fit the locker anyway. I wont be doing the engineering myself and am having trouble finding the time just to do the diff swap.
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Re: diff ratios and related things

Postby isuzurob » Sun Mar 01, 2015 6:23 am

if you are fitting the locker to the 4.5, from memory you have an air locker, so the complete centre of the 4.5 will not be used, will just use the crownwheel and pinion out of the 4.5 and the carrier/locker assembly out of the 4.3, which will give you your locked 4.5 rear diff, its a shame when that locker was in a 4.5 already
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Re: diff ratios and related things

Postby geeves » Sun Mar 01, 2015 3:57 pm

True. That 4.5 was left with the engineer that swapped it over in bits. Over a year ago and in his scrap bin :cry:
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Re: diff ratios and related things

Postby isuzurob » Sun Mar 01, 2015 4:31 pm

Thats always the way, you could always just change the front diff, but thats more time consuming, but then you could fit a locker to the front aswell, as said before 4.5 ratio is better for 4x4 though
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Re: diff ratios and related things

Postby geeves » Mon Mar 02, 2015 2:56 pm

defiantly keeping 4.5
Out of interest how many 3.1 bighorns out there have the option code hc6 for factory 4.5 diffs?
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Re: diff ratios and related things

Postby slightlydodgy » Mon Mar 02, 2015 4:02 pm

geeves wrote:defiantly keeping 4.5

That's fighting talk!! :twisted:
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Re: diff ratios and related things

Postby geeves » Mon Mar 02, 2015 4:29 pm

Not really. 4.5 is the best option and have you looked at how much work is involved in changing the front?
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Re: diff ratios and related things

Postby slightlydodgy » Tue Mar 03, 2015 4:45 am

I was referring to your being defiant in keeping the 4.5 instead of definite :D
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Re: diff ratios and related things

Postby geeves » Tue Mar 03, 2015 2:00 pm

Ill let that go as long as you have another isuzu by years end
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Re: diff ratios and related things

Postby isuzurob » Tue Mar 03, 2015 4:56 pm

fronts arnt to bad to get out, worse than rear though, i have some 4.3 front diffs aswell, but that will put your speedo out aswell, if you get stuck i can dig out that 4.5 rear, i also have a 2.6 petrol that should have 4.5 diffs now that i think about it also
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Re: diff ratios and related things

Postby geeves » Tue Mar 03, 2015 6:23 pm

Ok just had a look at the 4.5 I have Crown wheel and pinion are fine. If you told me they had done 5000km I would believe you. Backlash is fine Bearings dont seem to be rough.
But whos been eating my spider gears?
What causes this
diff1.jpg

diff2.jpg
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Sanding your knuckles before starting work can help. That way you cant skin them
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