lower crawl ratio -80:1

[Glenn-BJ74]

The BJ74 crawl ratio is 46:1 with the stock low range gear of 2.295.(4.11 diff X 2.295 low range X 4.843 1st gear)


Marks gears (from Australia) can reduce the low range to 3.07, which achieves a 61:1 crawl ratio. Cost about $1400 us for parts plus install - big plus is no drive line modifications.
What other options are there ??? the above option is expensive for what it achieves.

 

[Josie'sLandCruiser]

Hi All:

Add a pair of 5.29 ratio diff gears to that Mark's 3.07 t-case gear set will net you a crawl ration of about 78:1.

Regards,

Alan

 

[bj70_guy]

Marlin Toybox?

Does the 74 really have 2.295 T-case gears? I assumed they were the same as the 70s - 1.99:1

How big a tire are you planning to run?

 

[lowenbrau]

Marlin Toybox?

Does the 74 really have 2.295 T-case gears? I assumed they were the same as the 70s - 1.99:1

How big a tire are you planning to run?

1.99:1 is what my BJ74 is. 2.3 in my BJ70.

Best bang for the buck is a Marlin toybox I figure. You add 4.7:1 to the middle of your rig and end up with about 170:1 low range.

My truck needs some lower highway gears as well so I'm contemplating swapping in a Rover LT230 case. 1.2:1 high range and 3.3:1 low.

 

[bj70_guy]

1.99:1 is what my BJ74 is. 2.3 in my BJ70.

Best bang for the buck is a Marlin toybox I figure. You add 4.7:1 to the middle of your rig and end up with about 170:1 low range.

My truck needs some lower highway gears as well so I'm contemplating swapping in a Rover LT230 case. 1.2:1 high range and 3.3:1 low.

Hmm - did your bj70 t-case (or t-case gears) come out of an auto HJ, by any chance? I really thought all the bj70s were only 1.99:1

Has anyone racked up any big miles on a Toybox yet? I'm curious how they work out in the long haul. I like the "one less thing to screw up" factor of the Mark's gears, but you can't beat that kind of low range with the Toybox.

 

[lowenbrau]

Hmm - did your bj70 t-case (or t-case gears) come out of an auto HJ, by any chance? I really thought all the bj70s were only 1.99:1

Has anyone racked up any big miles on a Toybox yet? I'm curious how they work out in the long haul. I like the "one less thing to screw up" factor of the Mark's gears, but you can't beat that kind of low range with the Toybox.

'86 and '87 cdn spec t-cases behind the H55f had 2.296

I have no idea why the jdms went backward. Matches the 4:11s vs the 3.7s in the cdn stuff I guess.

Toybox is just a mini case in high range. Not really any durability liability that I can see. You get enough torque multiplication to do some big damage in low range though.

 

[bj70_guy]

'86 and '87 cdn spec t-cases behind the H55f had 2.296

Well there you go. I had no idea.

Toybox is just a mini case in high range. Not really any durability liability that I can see. You get enough torque multiplication to do some big damage in low range though.

Damn it. Just when I thought I had my 74 build plan figured out...

 

[Greg_B]

Toybox is just a mini case in high range. Not really any durability liability that I can see. You get enough torque multiplication to do some big damage in low range though.

Bruce, for Norms processing of options...still best to pick up a 4spd case for behind the Toybox, or do you know if this has this been addressed?

***Says he who has one...still sitting on the shelf***

gb

 

[lowenbrau]

Bruce, for Norms processing of options...still best to pick up a 4spd case for behind the Toybox, or do you know if this has this been addressed?

***Says he who has one...still sitting on the shelf***

gb

Either will work. If you are stuck on having a switch to engage the front driveshaft ( a must with rhd, I think) you'll have to re-use the five speed case. My plan was to send mine to Marlin and get him to put the box in the middle. Not becaasue I can't do it myself but because I don't think they've ever done one. I think that's why they still don't advertise the kit.

FWIW the toybox fits in the BJ74 like Toyota planned for it.

 

[Glenn-BJ74]

What is involved -Toybox

Not knowing much about this - what is involved to install a Toybox in BJ74 and why might it work iso well on a BJ74?

• a Toy truck pu t-case from the wreckers (year?)
• moving trans support back (kit for that?)
• shortening drive shaft
• kit from marlin
• cutting trans tunnel for extra stick?
• anything elsewhere

what would be ballpark cost for parts and machining?

 

[UpsideDown]

Just a bit of info here...


The 4 speeds from BJ42s and BJ60s in Canada had 2.276 gear ratios. They use the smaller idler shaft. The H55 equipped BJ6xs had 1.959 ratios (or whatever the third decimal is).

The automatics (from HJ6x) had 2.55s and use the larger idler shaft in the 'case. There are some other differences too (bearing configurations).

The mount for the H55 goes under the transmission and would not get relocated.

You would want a gear drive Hilux gear reduction box (plentiful in wrecking yards for a fair price).

Driveshaft length changes, mods to the tranny cross member for the longer front shaft.

For local fourwheeling, a crawl ratio for a BJ7x is getting decent in the mid 40s when using 33s or 35s, but could use some serious improvement for Moab and Rubicon conditions or when you want to have more control.

The ballpark is highly variable depending on what you're prepared to do yourself and what you're going to farm out. It's not going to be cheap, that's for sure.

~John

Not knowing much about this - what is involved to install a Toybox in BJ74 and why might it work iso well on a BJ74?

• a Toy truck pu t-case from the wreckers (year?)
• moving trans support back (kit for that?)
• shortening drive shaft
• kit from marlin
• cutting trans tunnel for extra stick?
• anything elsewhere

what would be ballpark cost for parts and machining?

 

[lowenbrau]

A couple of additions to John's info.

You have to lose the transmission mount and crossmember altogether in order to clear the front ds unless you have a nearly stock height truck. You replace it with something you fabricate to make use of the mini truck case mount. there is a lot of aftermarket support for these.

I think making your own adapters and using junkyard cases is false economy. Marlin prepares the whole kit and manufactures a 4.7:1 low range gear for the mini reduction section that has some improved design eleminating some weaker points on the factory shaft. Its $1900 and will give you all the low range options you could ever want. It also gets your drive shafts pretty close to the same length (in a BJ74) which eleminates the need for a cut and turn of the front housing if you springover on stock springs.

I thing 60:1 is the bare minimum for any kind of techinical wheeling

Mark's has a planetary option for the split gase as well. Its probably about the same money when you calculate the required mods.

 

[Axel Von Gardan]

My low range gear ratio is now 2.75:1, original is 1.99:1 (I suppose..?)
This gear ratio is by one finnish man who made those parts himself, gears are changed to low range, I´m planning to send these parts to other guy who changes high gear gears ;p (funny word, sorry bad english), only by changing that high gear gears, will low gear ratio set to 3.05:1
By changing those both, will final ratio be over 4:1, that supposed to be slow enough for swamp crawling , I think nobody here has done that before and I´m thinking can my axles handle that much torgue, not stock engine.