Split case gearing: lower low range stock gears. (1 Viewer)

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stevebradford

stevebradford

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Stumbled across some info about split case gearing.

Early 34mm split cases behind the h42 4 speed have a lower low range (2.276) than the later split cases also 34mm idler that came behind the h55 (1.959). So by swapping the gear sets you end up with a bit lower low range!

38mm split cases in the 62s aparently also have the lower low range (2.296) versus the 60 split case also with the 38mm idler (1.959). Again swapping gears is all thats needed.

Apparently @seapotato might have done this before... who knew he was such a wealth of information. was it worth doing?

Gear ratios.
TLC FAQ - 8.1 Transmission & transfer Case Ratios (All :1)
 
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I was wondering if anyone knew If a split case from an auto fj62 fit on a h42 trans with minor modifications ?
 
I believe it will with shorter bolts and different spacers. You would also need to tap and plug this hole.
IMG_2794.jpg


A little reading on split cases. The Wagon Way

If you would rather have a manual split case you can convert your vacuum to manual.

The Wagon Way

Vacuum to Manual t-case conversion
 
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No the H42 case should be a 34mm idler and the 62 case should be a 38mm idler they won't be able to swap parts. The idler shaft can be measured in place this circled is the idler.
IMG_2820.JPG
However just useing your better 62 case will keep your vacuum shift and 4h button. You might need to use the mounting bolts from the early case. I'm not sure what was used when it was coupled to an auto tranny.
IMG_2822.JPG
The bolt patterns are the same between cases there are a few differences. im not sure about ones that come off an auto tranny. That hole needs to be plugged on the manual 38mm tcases. Also on manual tcases the bearing on the output shaft of the transmission is at different depths into the front plate of the transfer case.
IMG_2821.JPG
So that would need a different spacer.
IMG_2819.JPG


This article covers it well. The Wagon Way
IMG_2823.PNG
 
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Does any one know the actual gear ratios?
 
I did some reading as I was thinking of doing this swap the next time I have my tcase apart.

found this.
C2E84C83-D8D0-4F49-BB8C-56D88C0F379B.jpeg

From here.
TLC FAQ - 8.1 Transmission & transfer Case Ratios (All :1)

A bit more in here.
The Wagon Way
Manufacture dates may be of more help in determining ratio’s. Or knowing what rig the t-case came out of, for example auto’s had a low range in the t-case of 2.29 (4/86-1/90). US market 60’s used a 2.27 low range (8/80-4/86) and you will find some Canadian rigs that have a low range of only 1.9 (non US models), mostly I do believe these were installed behind early H55’s. Which appeared in Canada as early as 1983 while spacer style trannys didn’t appear until approximately 1985 in the US. And I have to admit I am not sure what ratio low range was installed in the spacer style 4 speeds that were sold in the US market from 85 to 87 but it should be a 2.27 low.

Links to all this from here.
Some info saved
 
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I think read this thread: some h55f and split case tech

This is where I get most of my tech info as well for gearing etc. Technical Information

Advance Adapters has low range gear sets, they are preferred over the Marks kits but remember you will lose a
bit of overdrive with the low range kits, and there will be t case gear noise which you have to learn to live with.
 
Plus some clearance needs to be made by grinding few of the ribs inside the tcase.. I think George has a small mill in his shop that uses for making the space..
24550576_1873197236326739_991530207_n.jpg
 
Must be hard to take a new H55 and buck off the output shaft..:hmm:
24550415_1873197259660070_1335794159_n.jpg
 
Gotta say never seen that failure before..seen the splines on the output stripped..Marks gears from Australia offers a few gear options that runs much longer splines on the gear to prevent this wear. GS Cruiser parts put one in a h55 behind a 1hdt with modded turbo, thing pulled so damn hard.

Cruiser pilot could tell you Marks gears offers a spacer and only 34 mm ideler shaft with there kit, if you have the 38mm then no spacer needed.. No thrust washers are used, discarded them and preload the idler off the back of the case with a nut. Wade in if I made a mistake Johnathon.

Been so long since I was into a TCase, but I think they eliminated a spacer and build that into the gear for the extra length or splines for strength.


Those pictures of the H55 black box are from the weekend past, me and George were chatting about something else while he was building this unit. Couple little things NWF needs to change in order for the installation to be seamless.. without the changes George said it was an extra 5 hours into the install.
 
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Tcase for the autos is completely solo to the auto if memory serves me..
 
Who knew! So is it the entire gear set you need to swap or just a couple?
 
Bluebj42 said:
Who knew! So is it the entire gear set you need to swap or just a couple?
Click to expand...
Whole shebang from 4 speed into the 5. I have a couple boxes full of 5 speed tcase gears. Maybe I should make a paper weight or something...:lol:


Only goes from 1.9x to 2.3x (ish) not exactly life changing...but if you have the parts and the tcase apart, why not?
 
Well since my t-case is about to implode I might as well do the lower gears.
 
Good call!
 
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