Reduction gear selection

[GUte]

Guys im torn between choosing either 43% or 85% Marks 4wd (Gearmaster) transfer case reduction gears for my GU.

I have well and truly found the lower limits of the standard low range gearing while climbing hills and being bogged in thick slop, often requiring heavy clutch riding just to keep the wheels turning.

I have always thought, if im doing a job I may as well do it properly and get the 85% gears!

But recently have been wondering if 43 will be enough? I do a bit of beach work during summer so 43 are generally more suited to this. But then I may upgrade to 35" tyres when the time comes to replace them so the 43% may not be enough? Then comes the turbo/cooler upgrades which may mean the 43 will be enough with the big tyres? But if im running bigger tyres, I may need to change to higher diff ratios anyway so if im running 83%, these may we too high with the 35's and turbo/cooler/diff upgrades?

Im not fussed about down hill's as the standard engine braking and manual box holds things pretty well. Its uphill control that im chasing! would love to idle up some pretty snotty hills.
Also thinking, 85% gives approx 30kmh top speed in 5th, if you are doing 20-30kmh in 4L surely it can be done in 4H or even 2H.

I generally run on the beach in 3rd now, so 43% will probably switch to 4th, 85% will require switching to 5th for the same stretch.
Dont plan on doing any simpson desert crossings so momentum for big sand hills isnt really a concers

I guess I can handle some time on the knobby lever as I dont like to run 4L when I dont need to anyway

So much has been running through my mind lately so Im hoping anyone that has ever driven a patrol with reduction gears to chip in about their experience

It also doesnt help that the 43 gears are $135 cheaper and dont require machining of the case to get the gears in!

ARRGH!

Want to buy them soon but its a big expense and would hate to regret buying the wrong set!

Cheers!

[Maxhead]

Mate, do you know anyone running the 43's and 85's. If you could go for a spin you could easily decide.

I would have thought 85's would be way too high for a manual trans. I've got and auto and was thinking 43's myself but it all depend on your application I suppose.

Good luck mate

[Bigrig]

I'm going 85% on Friday this week, but as Kris alluded to, I have an auto which runs away a lot more than a manual. If I had a manual (and diesel even more so) I would definitely only be going 43%. I do more hill work than mud and having to change in and out of 4 low to 4 high between attempts is a small price to pay for the added reduction to the auto.

Living in south east QLD I have been beach driving for 22 years and rarely use 4 Low. I've been bogged once and even then, it was my fault as I didn't deflate the tyres and it was on the first cutting onto the beach. That said, my previous rigs were diesel manuals (bar one of six).

43% would be ample and to be honest, I don't think you'd be driving in 4 low at all on the beach except for heavy going as even in 5th, you'd be doing about 25klms per hour maximum with 85% reduction!

Just my opinion mate for what it's worth - good luck with it - either way, you're going to notice a huge improvement for hill climbs and descents, etc!!!

[GUte]

Cheers guys, yeah thats what I have been thinking lately, wanted 85 at first for ages now thinking 43 will probably be best of both worlds! Mind changes almost hourly sometimes!

I dont know anyone personally with a set fitted so I will just have to go on opinions alone

[Bigrig]

Cheers guys, yeah thats what I have been thinking lately, wanted 85 at first for ages now thinking 43 will probably be best of both worlds! Mind changes almost hourly sometimes!

I dont know anyone personally with a set fitted so I will just have to go on opinions alone

Talk to the guys at Marks Adapters mate - they are usually pretty willing to chat about the pros and cons of each and when I spoke to them, they weren't overly pushy on the sale factor, just which one would suit.

[gec]

If you fit reduction gears you will more than likely try more slow technical stuff then you will want the lowest gear possible, when I can afford it I will be fitting the 85s for sure.

[GUte]

Im hearing ya gec

I know of a few local hills that I wont even attempt with the current gearing and not even sure if 43% will be low enough. I have much more fun climbing hills than playing in mud/sand. With tyres deflated, I dont have any dramas running on the beach in 4H, future 4.3 diff ratios will make it even easier.

Sent an email to Marks 4wd and there are a few distributors in Perth so I will contact them to see if they have some in stock and go from there.

Still thinking 85!! haha

[Maxhead]

I find the only time i wish I had reduction gears is declines, especially in the mud/wet. Everything else is no problem. Mine's an auto tho
I have been in a few situations in the wet where the auto tends to run away and you need to use brakes( bad move). There are other techniques you can use without dropping the gears...I'm still to master those

[DX grunt]

Toss a coin. lol

Seriously... It's a big decision so do your homework.

All the best.

Take care out there.

Ross

[Bigrig]

I dunno ... Hate to be the voice of reason, but 85% reduction in a manual means that is about all he'll be doing in low range - extreme climbs and descents ... worthless for most beach work, worthless for most bush work and truth be told, not much chop for mud either as you can't build any real momentum ... may as well turn it into a comp truck!! lol

Example - my missus' jeep has standard overall low range ratio (as an auto) of 2.6:1 ... mine is 2.02:1 ... hers absolutely crawls downhill compared to mine running away (she'd be doing 4-5kph when I would be doing 18-20). A 43% reduction takes me to around 2.85:1 which would be plenty, but as said, I only use low range for the hill work I like to do, hence going 85% which will sit it around 3.45:1 - which is awesome. That's starting from 2.02:1 but what is the manual starting at? If you end up with reduction ratio of somewhere near 3.8-4.0:1, you will be crawling in low range even in fifth gear - and I mean crawling ... someone correct me and happy to be wrong, but even though you can use 3rd, 4th and 5th gear to start off with in Low range for ascents and mud etc, it's not what your transmission (not transfer case) was intended for and you end up stripping (potentially) gears that are smaller and not meant for the stress and abuse the shorter gears are meant to handle ...

Just my pickled view though ... I'll shut up now and go back to my box ...