Need help understanding low range gear in an Aussie 75 series split case (1 Viewer)

[calen]

did some searching and couldnt find what i needed so I hope someone has the answer. I have a hj47 that the PO swapped an h55f into from a 60 series and added a split case from a 75 ute. on the weekend I blew a hole in the front of the case on a rock and drove it dry and full of mud for while before noticing. at that point it was too late to save it as we were 4 hours from civilization and 6 more hours from home. drove it all the way back after patching with epoxy putty and flushing and refilling. sounded liek a jet fightter cockpit on the highway. I need to replace the tcase, and i want to take this opportunity (lol) to add lower range gears. I just want to know what the lo ratio I currently have is so I can mentally compare it to what i might put in. Ive looked for the stock ratio and found the Marks 4wd crusier gear ratio list, but in the spot for hzj75 tcase it says it has a one piece case? I thought all the cruiser cases were split? this is a plit case from an ausie 75. is this a typo? an if anyone just knows what the lo ratio is is id love to know.

thanks!

 

[Hulsty]

Aussie split case, 1.9 ratio most likely. If you want deeper low range hunt around locally for a 2.3 ratio case, Mines from a late auto 60 series.

 

[rick_d]

Like Hulsty said most likely a 1.99:1 stock case. You will need a H55 compatible case so no early 1981-1985 cases. Any 1986 (10/85 gives you 38mm idler) up to 1999 will be fine. Gear sets are a trick. Mark’s and terrain tamer gears have better options but can be loud. The 2.28 factory gear set was often put behind 4spds in US and elsewhere. I don’t know how easy to find anymore.

LOW GEARED RATIO KIT TRANSFER CASE 1.100-2.449 28% REDUCTION

LOW GEARED RATIO KIT TRANSFER CASE 1.100-2.449 28% REDUCTION

www.terraintamer.com

 

[calen]

Like Hulsty said most likely a 1.99:1 stock case. You will need a H55 compatible case so no early 1981-1985 cases. Any 1986 (10/85 gives you 38mm idler) up to 1999 will be fine. Gear sets are a trick. Mark’s and terrain tamer gears have better options but can be loud. The 2.28 factory gear set was often put behind 4spds in US and elsewhere. I don’t know how easy to find anymore.

LOW GEARED RATIO KIT TRANSFER CASE 1.100-2.449 28% REDUCTION

LOW GEARED RATIO KIT TRANSFER CASE 1.100-2.449 28% REDUCTION

www.terraintamer.com

awesome, thanks for this. I read a bout marks being loud, is that only in lo? or is it considered loud in 2 hi as well? I think i can handle some whine when im in 4 low. i never mind a little noise as long as its sposed to make noise haha wondering if anyone with a 75 or a troopy could recommend a low range choice that makes 4lo 3rd my old 4lo 2nd. i need a tutor to really understand the actual gear ratio math lol. i was thinking just to go all the way with 4:1, but someone mentioned that i might not have a "rip it up the steep hill" gear anymore. which i dont want to loose. I like "ripping up the steep hill" hahaha.

 

[JuanJ]

Hello,

If I remember correctly, the ratio changed to 2.33:1 in 1999 with 70 Series trucks.

You should be fine with the older 1.99:1 in your application.





Juan

 

[calen]

Hello,

If I remember correctly, the ratio changed to 2.33:1 in 1999 with 70 Series trucks.

You should be fine with the older 1.99:1 in your application.





Juan

ok thanks, then im guessing 2.33 is whats currently in my box. so 1.99 wont do. haha cant be going faster now. looking to go slower. hoping someone's done a 3:1 or a 4:1 and can chime in on ability to tear up a hill in 2nd or thrid.

 

[coldtaco]

don't understand your question. tear up a hill in 2nd or 3rd? why wouldn't you be able to in 4LO? 4Hi -low range gearing would have no part in how it would do tear up a hill in 2nd or 3rd gear? how fast is tearing up a hill? if you have 4:1 LO then the rpm's would be higher than 3:1 LO for same mph. just have installed 4:1 LO in my split case and it crawled up a 20 degree plus slope without any issues, in first gear, but I wasn't tearing up it.

 

[calen]

don't understand your question. tear up a hill in 2nd or 3rd? why wouldn't you be able to in 4LO? 4Hi -low range gearing would have no part in how it would do tear up a hill in 2nd or 3rd gear? how fast is tearing up a hill? if you have 4:1 LO then the rpm's would be higher than 3:1 LO for same mph. just have installed 4:1 LO in my split case and it crawled up a 20 degree plus slope without any issues, in first gear, but I wasn't tearing up it.

I know "tearing up a hill" isnt a scientific term or anything, but it was said by another member and I understood what they meant. there are many steep long hills I can crawl up currently, but inevitably you will meet a hill that is long enough and loose enough that crawling is not going to do it. you need to "rip up that hill". Right now, that gear for me is 4lo 2nd or third. I can go fast enough to use momentum to climb but still doesn't loose power at the top. Im affraid of gearing so low that the only "fast" gear ill have is 4th or 5th hahah which I dont know much about, but have heard that applying that type of torque to isnt good. the hill at 5:11 is the type of hill im talking about. one shot, I was in 3rd lo and might have shifted into 2nd a third of the way up, I cant remember. either way i was mashing, and I could not done that hill in 4lo 1st no mater what. it needed momentum. so I jsut want ot make sure I pick a ratio that leaves me still with a strong gear I can use for momentum climbing. Maybe everything Ive heard is BS and its fine to mash up a hill in 4lo 5th. in that case I dont have a pronblem.

hope all that makes sense. thanks for any input.

 

[coldtaco]

Ah… I understand now. Unfortunately I don’t have a answer for you

 

[JuanJ]

ok thanks, then im guessing 2.33 is whats currently in my box. so 1.99 wont do. haha cant be going faster now. looking to go slower. hoping someone's done a 3:1 or a 4:1 and can chime in on ability to tear up a hill in 2nd or third.

Hello,

In low range with 2.33:1, you cannot go beyond 40 km/h in fourth/fifth gear. I think you can travel around 45 km/h using 1.99:1.

A 3:1 or 4:1 ratio will be even slower.

Patience and the right gear are your friends on steep hills. On steep, muddy slopes, a realistic speed with low range is around 25 km/h, mostly in third gear, with the occasional down shift to second gear (and rear locker on if you have it) to keep momentum. But that is just me.





Juan

 

[calen]

Hello,

In low range with 2.33:1, you cannot go beyond 40 km/h in fourth/fifth gear. I think you can travel around 45 km/h using 1.99:1.

A 3:1 or 4:1 ratio will be even slower.

Patience and the right gear are your friends on steep hills. On steep, muddy slopes, a realistic speed with low range is around 25 km/h, mostly in third gear, with the occasional down shift to second gear (and rear locker on if you have it) to keep momentum. But that is just me.





Juan

Im not completely ignorant of gears, just the math to achieve exactly what im looking for. very aware that the first number goes up your speed goes down. im not trying to "go fast" Im trying to go fast in reasonable relation to hill climbing. if you watch the part of the video i posted, i said before, hills like that will not be climbed via crawling. physics will not allow it, doesn't matter how patient you are, you will just dig four holes. same goes for sand. there are plenty of times where "speed" is a must and i put speed in quotes cause were talking low range. I must not be communicating this clear enough, cause what im talking about is a mandatory aspect of off roading. everyone has had to gas it up a hill as opposed to crawling up it from time to time. most videos honestly of people climbing hills is a send. i dont want to loose my ability to "send it". all said, im pretty sure if i go with 3:1 3rd 4lo is gonna be my "rip it up the hill gear" and ill be good.

 

[AirheadNut]

I've found this to be extremely helpful in comparing gearing options and getting a good visual of what different ratios will produce: Gearing Analyzer with Shift Tracer - https://www.blocklayer.com/rpm-gear

 

[AussieHJCruza]

My marks gears were loud in low and high range, 1st low with H55, 4.11 diffs, 35s is very slow, fantastic control on steep descents, but you'd probably be a gear higher than before anywhere you're after a bit more wheel speed

 

[calen]

My marks gears were loud in low and high range, 1st low with H55, 4.11 diffs, 35s is very slow, fantastic control on steep descents, but you'd probably be a gear higher than before anywhere you're after a bit more wheel speed

THis is what im looking for! thank you. I want to throw 35s on eventually. right now with 33s on the street 1st is hardly useful, so I hoping that with 35s street driving will be perfect, and higher speeds at lower rpm on the highway. Then in 4lo and the 3:1 gears the crawl will be still slower then the stock low gears on 33s im guessing you have a 2h? turboed? hows the highway hills on the 35s?

 

[Guyute]

I've found this to be extremely helpful in comparing gearing options and getting a good visual of what different ratios will produce: Gearing Analyzer with Shift Tracer - https://www.blocklayer.com/rpm-gear

That is a good gear calc page. Thanks for sharing.

 

[AussieHJCruza]

THis is what im looking for! thank you. I want to throw 35s on eventually. right now with 33s on the street 1st is hardly useful, so I hoping that with 35s street driving will be perfect, and higher speeds at lower rpm on the highway. Then in 4lo and the 3:1 gears the crawl will be still slower then the stock low gears on 33s im guessing you have a 2h? turboed? hows the highway hills on the 35s?

First gear is perfect with 4.11 and 35s on the street. Makes it much more useful.
She does fine on the hills with lots of fuel... supercharged 3F-E out of an FJ80

 

[calen]

First gear is perfect with 4.11 and 35s on the street. Makes it much more useful.
She does fine on the hills with lots of fuel... supercharged 3F-E out of an FJ80

ahhhhh ya gotta some more torque in there. hahah, Im sure Ill be fine. eventually itl get a diff motor