4.0:1 Split Case Gears

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Yes - no change to high end.

I don’t get the link you’re making between low range gearing and highway capability. I have two rigs with 4:1 that do great on the highway at 75
 
workingdog said:
Yes - no change to high end.

I don’t get the link you’re making between low range gearing and highway capability. I have two rigs with 4:1 that do great on the highway at 75
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Yeah, but do the 4.0:1 have underdrive ratio’s or do the high range gears remain 1:1? I believe what he is asking is exactly what I have endured with my low range gears, will they be a noisy whine at highway
speeds?
 
The high range are unchanged at 1:1 in the 4:1 cases - at least the one done by AA. I know a few split cases that are noisy (doesn't matter if they are 4:1 or not) on the highway. The Atlas 4:1 is not noisy and my 4:1 split case was noisy at the beginning, but it is more or less quiet now.
 
Like all gears, they wear in and usually get quieter. Have you tried different fluids. A lot of synthetic oils are thinner, even though they are the same weight of oil. There are tons of threads on the subject and some of the bigger shops specify a thicker dino based oil for a variety of reasons. I think I might experiment with some climbing gear lube or the 140w stuff before I would throw in the towel on a set of gears.
 
workingdog said:
Yes - no change to high end.
I don’t get the link you’re making between low range gearing and highway capability. I have two rigs with 4:1 that do great on the highway at 75
Click to expand...
cruiserpilot said:
Yeah, but do the 4.0:1 have underdrive ratio’s or do the high range gears remain 1:1?
Click to expand...
workingdog said:
The high range are unchanged at 1:1 in the 4:1 cases - at least the one done by AA.
Click to expand...


Straight from Advance Adapters website page for the 4.0:1 gearsets:
"Note: This Gear set will also alter your high range ratio. The high range ratio will now result in a 10% underdrive."

716938 : Toyota FJ60/62 4.0:1 Low Range Gear Set for Transfer Caseswith a 38MM Intermediate Shaft. 34MM cases require the additional kit 716934. | Advance Adapters

4.0:1 Low Range Gear Set for 1980 - 1990 Toyota FJ60 Transfer Cases Having a 19 Spline Input Shaft and a 38MM Cluster Pin.This gear set is designed for the 38MM cluster pin case, however; we offer a stepped cluster pin that works for the 34MM case and u...
www.advanceadapters.com www.advanceadapters.com

What I was getting at, is that I would like to keep my high range 1:1 most likely, so that I can keep the most optimum highway cruising RPM for fuel efficiency and fuel range, and I would like to find a good low range gear set around 3.1:1 that does not underdrive the high range ratio.
 
Chuck78 said:
Straight from Advance Adapters website page for the 4.0:1 gearsets:
"Note: This Gear set will also alter your high range ratio. The high range ratio will now result in a 10% underdrive."

716938 : Toyota FJ60/62 4.0:1 Low Range Gear Set for Transfer Caseswith a 38MM Intermediate Shaft. 34MM cases require the additional kit 716934. | Advance Adapters

4.0:1 Low Range Gear Set for 1980 - 1990 Toyota FJ60 Transfer Cases Having a 19 Spline Input Shaft and a 38MM Cluster Pin.This gear set is designed for the 38MM cluster pin case, however; we offer a stepped cluster pin that works for the 34MM case and u...
www.advanceadapters.com www.advanceadapters.com

What I was getting at, is that I would like to keep my high range 1:1 most likely, so that I can keep the most optimum highway cruising RPM for fuel efficiency and fuel range, and I would like to find a good low range gear set around 3.1:1 that does not underdrive the high range ratio.
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3:1 Low Range Gear Reduction Set- Split Case 4/1986-1/1990 6x/7x Series
Fits Split-Cases with 38mm* Idler Shaft, also fits 1990+ non US 7x/8x split style transfer cases, please call with VIN for verification. 1:1 High Range. Requires minor clearancing to case housing. Made in Japan to OE Toyota specifications. Includes idler gear and low-speed output gear.
Part# TCG869031 - $650.00

3:1 kit doesn’t change the high gear cluster. It’s 1:1 in high range and won’t effect your gearing in the highway. If you use the 3.3 or 4:1 kits you will change out the high range gear cluster and have a reduction in highway/driving gearing.

The above is from Cruiser Outfitters site. Check them out.

 
You are right. I was wrong. From AA site "
Note: This Gear set will also alter your high range ratio. The high range ratio will now result in a 10% underdrive.

I apologize for the mis-information. I've been driving on the AA gear set for 2 years never realizing it was 10% underdrive. Now I'm going to notice it. Another vote for an Atlas when I go 4 link this summer.
 
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Looks like the TCG869031 3:1 kit is going to be the ticket for me then, thanks for the link.

Any idea if it's actually 3.1:1 as others are advertised? I've seen another advertised as 3.05:1 as well. They may likely all be the same gears aside from the Mark's 4WD gears being of different origin apparently.
3.1:1 would be a nice little extra bonus in trying to squeeze a little more crawl out of it. Stock is 2.28:1 if I recall correctly. 3:1 would be noticable, but just a hair more of a change from stock would be great as well.
 
Any idea anyone of what the Terrain Tamer R151F modified fully splined 5th gear shaft mod is all about, by the way? While I have it apart... May as well build it to be the ultimate in reliability
 
I think this has already been addressed but hewre's the short version:
1) the 4:1 low range gear set is ONLY available in conjunction 10% UD in high range. It's common ( and to be excpected ) to have some mild gear whine in both high and low range.
2) The 3:1 low range gear set does not affect high range. Therefore, high range will sound the same, low range will ( just like any aftermarket T-case gear set ) make some mild gear noise …..

We have all the gear sets on hand, including the high range OD and UD sets as well. And we have the factory E-brake components also.

Happy to help!

Georg

www.cruiser brothers.com

shop 209-475-8808
 
Resurrecting old thread again … so the 3:1 gear change for a 34MM 60 Tcase, will NOT effect 2 high ? I have a diesel and want to keep my RPMs as low as possible cruising on the highway. But lower the gearing when in 4L . How does the 4:1 change the 2H gearing when it’s 1:1?
 
William839 said:
Resurrecting old thread again … so the 3:1 gear change for a 34MM 60 Tcase, will NOT effect 2 high ? I have a diesel and want to keep my RPMs as low as possible cruising on the highway. But lower the gearing when in 4L . How does the 4:1 change the 2H gearing when it’s 1:1?
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Your question is answered multiple times in the prior posts, including the one directly before yours.

That being said. If you WANT to effect high-range AND want a lower low-range, you can use 10% overdrive or underdrive high-range gear sets in conjunction with the 3:1 low gears.

So you should consider the 10% OD High-range.

I’ve done several with the 10% OD / 3:1 low and its a nice way to get some top end without the cost of an H55 (or complication of install into, say, a 40 series)
 
cruisermatt said:
Your question is answered multiple times in the prior posts, including the one directly before yours.

That being said. If you WANT to effect high-range AND want a lower low-range, you can use 10% overdrive or underdrive high-range gear sets in conjunction with the 3:1 low gears.

So you should consider the 10% OD High-range.

I’ve done several with the 10% OD / 3:1 low and its a nice way to get some top end without the cost of an H55 (or complication of install into, say, a 40 series)
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Sorry I just wanted 100% clarification, I haven’t found any OD gears for 34MM Tcase . I have a 4L80E transmission in a 4bt swapped 80 , need to get my highway RPMs down, and the T case is already out and apart for a reseal, as to why I’m looking for this option.
 
William839 said:
Sorry I just wanted 100% clarification, I haven’t found any OD gears for 34MM Tcase . I have a 4L80E transmission in a 4bt swapped 80 , need to get my highway RPMs down, and the T case is already out and apart for a reseal, as to why I’m looking for this option.
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The UD/OD high-range sets won’t work with a 34mm gearset.
However - you could use the AA 34-38mm stepped idler shaft to make it a “38mm case”. Or bore the case to 38mm. Or get a 38mm case.
No matter what you will have to machine the case for 3:1 gears to clear
 
cruisermatt said:
The UD/OD high-range sets won’t work with a 34mm gearset.
However - you could use the AA 34-38mm stepped idler shaft to make it a “38mm case”. Or bore the case to 38mm. Or get a 38mm case.
No matter what you will have to machine the case for 3:1 gears to clear
Click to expand...
Copy that . Appreciate the help.
 
cruisermatt said:
The UD/OD high-range sets won’t work with a 34mm gearset.
However - you could use the AA 34-38mm stepped idler shaft to make it a “38mm case”. Or bore the case to 38mm. Or get a 38mm case.
No matter what you will have to machine the case for 3:1 gears to clear
Click to expand...

Matt nailed it!
If you want/need the OD, then you’ll want to source s 38mm case.
I’m also not a big fan of machining the 34mm cases for the lower gear sets; typically you have to tig weld 2-3 holes shut. That’s not an issue with the 38mm case.

We’re building a 38mm case fir my son tomorrow with the 3:1 low gears. I’ll post done pics. They’re going into his “HZJ25”.

Georg @ Valley Hybrids @ Cruiser Brothers
 
Here’s a preview to today’s “tech history day”.

Yesterday we rebuilt an H55F my sons HZJ25 project. We also built a new OEM 4:1 split case for our buddy Mark W.

Today we will be building two low geared transfer cases. The first one will be for my sons project and features 3:1 gears going on to his H55F we rebuilt yesterday.
The second split case we are building today has 4 to 1 low range gears. Our good friend and customer Tai Conlin will be building this transfer case onto his freshly rebuilt H55F transmission. We finished that transmission a couple of weeks ago.

Should make for a fun day. We have a number of customers and cruiser buddies joining us for today’s tech day.

Georg @ Valley Hybrids @ Cruiser Brothers

PS: did anybody notice that the H55F top cover in the pic is the “unicorn” 40-series version?!
😎

2B115D62-A3B3-480D-B33C-19DC7E59839D.webp
 
I was hoping to be able to machine my 34mm case for lower gears as the old gears are worn out and I can’t find any new ones
 
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