i was debating on one of these or the marks gears for the split tcase. id much prefer the 4-1, but, it reads like you need an AA factory mechanic to get this thing set up right...
i hadnt dug that deep into it, yet. basically i have an h55f and the stock t case is gonna get cracked open for a rebuild... i figured id like lower gearing, then i priced the gears.. pert near the cost of an orion, so i started looking into this option...
thats as far as i got before reading about it popping out of gear.
i handn't looked into splines yet. not something you wanna overlook though. (im used to GM drivetrains in my 40's, im new to a real toyota)
Many people who did have problems used parts that were worn, leading to the problems
AA has updated the original design and parts included to avoid these issues anyway.
I have only installed one set of the marks gears... Not a lot of datapoints there, but I was disappointed in the product and Marks support... AA (who was the middle man) was, as always excellent. As they have been with issues involving other things I have sourced from them.
The Orion is an EXCELLENT UNIT. But if you have a 19spline tranny it does not matter.
More info. on the transmission for us curious folk. Is there a diff. between h55f and h55 ? Was there any changes to this transmission during production or are they all the same ? Is the 3 to 1 gearset for t-case an aftermarket item or is that found in an oem t-case ?
The landcruiser 5-speed is the H55-f. There has been some discussion that an H55 (notice no 'f') may exist. I forget if it was a Dyna or 2wd Hino truck???
There is one major difference in the H55-f. It either bolt to a B series engine, or an H/F series engine (the difference lies in the input shafts).
A few minor differences come to mind:
steel vs aluminum bellhousing
an extra few degrees of clocking in the bellhousing (I think this change was incorporated with one of the above steel/Al bellhousings)
a crossmember that fits the 'clocked' or 'non-clocked' bellhousing
I believe if you get everything (tranny, bellhousing, crossmember) from the same donor you're fine. You may run into a few minor snags if you get the parts from different year donors (though they're not all that serious).
