Split Case Gearing Thoughts (1 Viewer)

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AlaskanWheeler

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I'm trying to solve some gearing solutions with my '81 on 38's. Running with 5.29 R&P is out of the question. If I run 4.88 with a 3.01:1 gear set such as MAN-A-FRE which has a high range of 1.08:1. Would this put me in the same ballpark as running 5.29 R&P gear sets? What are your opinions on running this set-up and has anybody had any troubles with these gear sets?
Thanks
 
wesintl said:
speaking of split cases which ones came with the 2.2 low?


85 and later...iirc...
 
AlaskanWheeler said:
I'm trying to solve some gearing solutions with my '81 on 38's. Running with 5.29 R&P is out of the question. If I run 4.88 with a 3.01:1 gear set such as MAN-A-FRE which has a high range of 1.08:1. Would this put me in the same ballpark as running 5.29 R&P gear sets? What are your opinions on running this set-up and has anybody had any troubles with these gear sets?
Thanks



The only 'drawback' if there is one with these Marks gear sets is that material from the inside of the tcase needs to be removed/sanded down, so that the gears clear. Not that big of a deal to me when I installed them in a 1983-40 series....


It would improve your gearing and make your truck more drivable on road, as well as off.

:beer:


Good luck!


-Steve
 
wesintl said:
does it coincide with the larger idler or no?



pretty sure that it does...


you could look at cluster gear sets on SOR's site and possibly come up with an exact date...




:beer:
 
Hi All:

It is my understanding that the early 'split t-cases (1981-84 US-spec FJ60) had the 2.28 to 1 low range reduction, whilest the later US-Spec FJ60s (1985-87) came with the 1.96 to 1 low range ratio.

Regards,

Alan
Seattle
 
wesintl said:
does it coincide with the larger idler or no?

As I understand it, *all* US-spec split cases mated to the H42 are 2.276:1, and those mated to Canadian-spec H55Fs are 1.99:1.

Mine for sure is 1.99:1 and it's got the larger (38mm) idler. My truck is a '91 and came stock with an H55F.
 
We all have different "understandings" but I'm pretty sure this is correct:

1.99:1, 34mm idler through the end of the 84 model year-9/84

2.26:1, 34mm idler 10/84-3/86

2.26:1, 38mm idler 4/86-end of 87 model year, manual shift

2.26:1, 38mm idler 88-89 model year, vacuum shift (and different shift forks inside)
 
Exiled said:
As I understand it, *all* US-spec split cases mated to the H42 are 2.276:1, and those mated to Canadian-spec H55Fs are 1.99:1.

Mine for sure is 1.99:1 and it's got the larger (38mm) idler. My truck is a '91 and came stock with an H55F.
This coincides with every split case w/ H42 or H55 that I have counted so far. The catalog does show a slightly different idler tooth count for4/86 and later, but there is one part number (and tooth count) for all E-3/86 USA split cases. I may not have counted teeth on a 4/86-later H42 T-case, so cannot comment on the ratio of those units.
 
THanks. I've searched and every thread comes up with differing assumptions just like this one and it's hard to decipher what is correct. I have a 34mm idler and I want to get a used case to rebuild and I might as well get the 2.276 with the larger 38mm idler but then I loose the ability case parts which I guess it negligable.Thanks Jim, Henry.
 
I've got a split case apart right now from an '84 with a 34 mm idler out of an H42. I can count it this afternoon and report back.... Now I just need to figure out which two gears to count :doh:
 
First, count the input gear and the front idler.
Then, count the back idler and the low output gear.
:banana:

Now divide front idler by input.
Divide low output by rear idler.
:banana: :banana:

Multiply the 2 results together.
:banana: :banana: :banana:

Hopefully you will end up with a number like 1.99 or 2.28 :bounce:
 
My '87 60 has the split case with 2.29:1 and 38mm idler.

M
 
I have the Marks gearset and I am happy with the performance, however... they do make a bit of noise. (It sounds like a ok 3 speed transfer case.) If you are used to the quietness of a split case
forget it. Dave
 
Hey Jim-
Thanks for the info. I will check next friday when I have access to my T-case and report back.


Seth
 
85 fj60 case

here's the innards of a split case from an oct 85 fj60

by trying to eyeball and count half the teeth and using Jim's formula I end up right around 2.28:1

my eyes aren't good enough to eyball plus or minus 2mm on the idler shaft
 

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