4.0:1 Split Case Gears

[cruisermatt]

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

What exactly is worn out on your gears?
And which gears haven’t you been able to find?

Like Georg said you can machine the 34mm case but it will punch thru the case and needs to have plates welded on. I’ve done this a few times on personal stuff. I’ve also opened up the bore in the case from 34 to 38mm a few times. If you have your own equipment this is fine but most don’t.

Another option that isn’t discussed often is buying a brand new bare 38mm housing (about $750) and send that to Georg (or me) to machine for the low gears.
You’d buy a 38mm rebuild kit which would have the idler shaft, all the bearings and seals, and re-use the shift forks and output shafts and output flanges from your 34mm case, or buy new.

 

[cruisermatt]

Kind of unrelated to the thread but here’s some pics of a new bare housing I used on a project a few months ago.

I sourced this one for a local customer restoring a Nicaraguan HJ45 who’s T-case ended up being almost completely unusable.

Built into a new H55f with long spline input gear and a really good used FJ62 takeout idler gear and output gears. New longer output shaft and parking brake drum. He ended up with a really nice combo without having to buy an entire new T-case which he hadn’t budgeted for, granted I gave him the FJ62 takeout stuff, also a note he would have had to buy the parking brake parts and input gear regardless since those don’t come with the new case assemblies.

Definitely some Cruiser Outfitters and Valley Hybrids goodies sprinkled in here. Glad to be able to work with these guys.

 

[William839]

The whole idea was to just refresh my case , it’s in a 4BT swapped 80, I’m not familiar with 60s too much so these T case differences are all new to me. The gears have play in between them ( input drive gear and idler gear have wear) they’re not horrible but would rather do this right the first time. If possible I would like to use what I have , but if I could source a new complete built t case that would work too , then I could put the OD and UD gears.

 

[cruisermatt]

The whole idea was to just refresh my case , it’s in a 4BT swapped 80, I’m not familiar with 60s too much so these T case differences are all new to me. The gears have play in between them ( input drive gear and idler gear have wear) they’re not horrible but would rather do this right the first time. If possible I would like to use what I have , but if I could source a new complete built t case that would work too , then I could put the OD and UD gears.

Ok, so that’s new information. Your situation is a bit specialized and will get a bit off topic from the original thread - but my thoughts/opinion on this.

The big downside with the OD gears is the input gear isn’t available in a long-spline configuration, when a brand new gear is installed onto a brand new H55f output shaft, all behind a 150hp 2F or 3FE this is no big deal but behind a 6BT in a heavier 80 series this can become a spot for some premature wear.

For your specific use-case my recommendation would be to change out your transmission adapter and put a HF2A (80series T-case in it). You can get Overdrive gears and 3:1 gears for that too. The splitcase is great but the HF2a’s are just better. Stronger case, bigger (and more) bearings, better oiling, better shaft support.
You can run that as AWD or put a part-time kit in it.

My opinion and experience is Cruiser drivetrain parts behind 4BT/6BT is just borrowed time. Just a completely different weight class of engine.

I just sold Georg (@orangefj45) a HF2A core a few weeks ago and I’m sure he’d love to rebuild it for you with all the goodies. I mostly stick to splitcase stuff.

Also - what transmission, tires and axle gears do you have?

 

[orangefj45]

We had a great turnout today for our “split case tech day”.
Tai and Garrett built their split cases onto H55F transmissions we recently rebuilt for them. One has the 4:1 low range gears, the other has 3:1 low range gears.

Georg @ Valley Hybrids @ Cruiser Brothers

 

[cruiseroutfit]

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?

Correct, 3:1 kit stays 1:1 in HR

The 4:1 changes as such:

Older chart, I'll post a newer one next week bit the basics are covered:

All the details here:

YWST: Low Range T-Case Gear Sets for the 1980-2007 Cruisers

Yeah, we stock that! Land Cruiser Transfer Case Low Range Gear Sets Sumo Gear sets are made to OE specifications in Japan. These popular gear sets offer transfer case gear reduction with the highest quality components on the market. Give us a call if you have any questions or would like to...

forum.ih8mud.com

PS, did you email our tech team about this same 3:1 - 1:1HR question yesterday? I could swear I saw some very similar questions they answered.

 

[William839]

Ok, so that’s new information. Your situation is a bit specialized and will get a bit off topic from the original thread - but my thoughts/opinion on this.

The big downside with the OD gears is the input gear isn’t available in a long-spline configuration, when a brand new gear is installed onto a brand new H55f output shaft, all behind a 150hp 2F or 3FE this is no big deal but behind a 6BT in a heavier 80 series this can become a spot for some premature wear.

For your specific use-case my recommendation would be to change out your transmission adapter and put a HF2A (80series T-case in it). You can get Overdrive gears and 3:1 gears for that too. The splitcase is great but the HF2a’s are just better. Stronger case, bigger (and more) bearings, better oiling, better shaft support.
You can run that as AWD or put a part-time kit in it.

My opinion and experience is Cruiser drivetrain parts behind 4BT/6BT is just borrowed time. Just a completely different weight class of engine.

I just sold Georg (@orangefj45) a HF2A core a few weeks ago and I’m sure he’d love to rebuild it for you with all the goodies. I mostly stick to splitcase stuff.

Also - what transmission, tires and axle gears do you have?

I’m running a 4L80E trans with advanced adapters adapter mated to the 1983 FJ60 Tcase , with stock 80 axles and stock gearing on 35s. I’m on a bit of a budget here so I would hope to not have to completely change everything. Was hoping to beef up the T case more during this rebuild if possible .

 

[cruisermatt]

I’m running a 4L80E trans with advanced adapters adapter mated to the 1983 FJ60 Tcase , with stock 80 axles and stock gearing on 35s. I’m on a bit of a budget here so I would hope to not have to completely change everything. Was hoping to beef up the T case more during this rebuild if possible .

I could see wanting a bit more top end with that setup, especially out west with the long highways to get places.

Three options for you really. None going to be cheap.
1. Swap to 38mm case with 10% OD gears
2. swap to Hf2A case with 10% OD gears (same result but stronger/more longevity), would need new adapter
3. Buy the 3.54 ring/pinion gears from Australia. Stock ring/pinion is 4.11 so this is a 14% bump but might kill your low range a bit. 3.54 Marks4wd differential gear install reports - https://forum.ih8mud.com/threads/3-54-marks4wd-differential-gear-install-reports.874243/

 

[William839]

I could see wanting a bit more top end with that setup, especially out west with the long highways to get places.

Three options for you really. None going to be cheap.
1. Swap to 38mm case with 10% OD gears
2. swap to Hf2A case with 10% OD gears (same result but stronger/more longevity), would need new adapter
3. Buy the 3.54 ring/pinion gears from Australia. Stock ring/pinion is 4.11 so this is a 14% bump but might kill your low range a bit. 3.54 Marks4wd differential gear install reports - https://forum.ih8mud.com/threads/3-54-marks4wd-differential-gear-install-reports.874243/

Looks like I will most likely go with a new 38MM case and build it with the OD gears , and the UD gears for a lower low range .
Appreciate the help. Regearing to 3.54s was what I was thinking before but like you said I hate to kill my low range like that, and I don’t really want to have to change my setup now with the FJ60 split case. As the 38mm should bolt right in to my existing AA adapter to my 4L80E.

 

[matzell]

I could see wanting a bit more top end with that setup, especially out west with the long highways to get places.

Three options for you really. None going to be cheap.
1. Swap to 38mm case with 10% OD gears
2. swap to Hf2A case with 10% OD gears (same result but stronger/more longevity), would need new adapter
3. Buy the 3.54 ring/pinion gears from Australia. Stock ring/pinion is 4.11 so this is a 14% bump but might kill your low range a bit. 3.54 Marks4wd differential gear install reports - https://forum.ih8mud.com/threads/3-54-marks4wd-differential-gear-install-reports.874243/

How fast do you want to go? haha! What am I missing Matt? My work truck has 4:10's and 33's behind a 6.0. It will go plenty fast. As far as the 34mm idler shaft, it is still bigger than a NP205 that came in one tone full size trucks. Not trying to bust any balls here, I just think the 34mm is plenty for almost any build. ?????

 

[cruisermatt]

How fast do you want to go? haha! What am I missing Matt? My work truck has 4:10's and 33's behind a 6.0. It will go plenty fast. As far as the 34mm idler shaft, it is still bigger than a NP205 that came in one tone full size trucks. Not trying to bust any balls here, I just think the 34mm is plenty for almost any build. ?????

I think you missed @William839 has a 6BT and is trying to keep RPM down. And the OD gears don’t mesh with the 34mm idler gear which is why the case change is required.

Also, a 205 idler pin isn’t in constant use down the freeway like a Cruiser case… direct center rear output.

Looks like I will most likely go with a new 38MM case and build it with the OD gears , and the UD gears for a lower low range .
Appreciate the help. Regearing to 3.54s was what I was thinking before but like you said I hate to kill my low range like that, and I don’t really want to have to change my setup now with the FJ60 split case. As the 38mm should bolt right in to my existing AA adapter to my 4L80E.

That would definitely be the most cost effective and bolt-in option.

I would love you help you get set up however Valley Hybrids (@orangefj45) or Cruiser Outfitters (@cruiseroutfit) will likely have a faster turnaround time then me.

 

[suzuguru]

I have a 1HDT I will be running in my 40, and I had previously planned to go with an H55F/Split Case setup with 4:1 gears. Would I be better off running an HF2A with part time kit? I know nothing about the latter, and have no idea if it would fit better in the 40. Don't know much about any of it, to be honest. I was very happy with the 4:1 gears in my Samurais, but have no experience with the 40's, let alone one with a 1HDT. Of course I'm looking to save money where I can, but I'm more concerned with a quality product that going to be reliable and last me a long time.

 

[William839]

I have a 1HDT I will be running in my 40, and I had previously planned to go with an H55F/Split Case setup with 4:1 gears. Would I be better off running an HF2A with part time kit? I know nothing about the latter, and have no idea if it would fit better in the 40. Don't know much about any of it, to be honest. I was very happy with the 4:1 gears in my Samurais, but have no experience with the 40's, let alone one with a 1HDT. Of course I'm looking to save money where I can, but I'm more concerned with a quality product that going to be reliable and last me a long time.

I’m going with a split case still , since it’s held up this entire time with no issues , I pulled it simply to refresh , but the gears had a little bit of wear and figured while it was out might as well upgrade . Pretty sure my 4BT has more power than a 1HDT . That’s just my experience but I trust all these guys way more

 

[William839]

I think you missed @William839 has a 6BT and is trying to keep RPM down. And the OD gears don’t mesh with the 34mm idler gear which is why the case change is required.

Also, a 205 idler pin isn’t in constant use down the freeway like a Cruiser case… direct center rear output.



That would definitely be the most cost effective and bolt-in option.

I would love you help you get set up however Valley Hybrids (@orangefj45) or Cruiser Outfitters (@cruiseroutfit) will likely have a faster turnaround time then me.

Appreciate the help a ton, sucks to have to fork out the money thinking this was gonna be a quick refresh, but if it’s an upgrade it’s worth it .

 

[suzuguru]

I’m going with a split case still , since it’s held up this entire time with no issues , I pulled it simply to refresh , but the gears had a little bit of wear and figured while it was out might as well upgrade . Pretty sure my 4BT has more power than a 1HDT . That’s just my experience but I trust all these guys way more

I would be curious to know the power and weight differences between a 1HDT and a Cummins 4BT, but that's a different subject.

 

[cruisermatt]

I would be curious to know the power and weight differences between a 1HDT and a Cummins 4BT, but that's a different subject.

Definitely stick with the splitcase in your 40.

In the case of the 4BT 80 that truck weighs like double a FJ40, hence my suggestion of the HF2A, which is the transfer case designed for an 80 series.
The differences on the cases in terms overall length and expense would not be worthwhile on a 40

 

[suzuguru]

@cruisermatt- Thanks for the info! I'll stick with the splitcase plan.