Topic: Need Help from Marlin please about tranny swap

[4bangr TJ]

I have a 1997 Jeep TJ with the 2.5L and the AX5. I was wanting to upgrade my tranny and possibly transfercase. I would like to install a r151 tranny with the 4.31 first gear from 86-87 toy turbo. Is this possible and what do I have to change to make it work. I have heard if you change the input shaft from an ax15 91 and older into this tranny to make up for the 1" difference will work but will I lose the low ratio first gear. Also I have also read that a R150 tranny from a 1996 and up toyota will work with just a bellhousing swap, on the marlin crawler website it shows that you can swap the gears out of the r150 in favour of the lower gear ratio of 5.15 is that true. Are all toyota tcases passenger side drop? will my np231 bolt up to a toyota tranny?

Thanks for any info I am sure you get asked alot of questions. 

[Ferg]

4bangr try this  http://board.marlincrawler.com/index.php?topic=1933.0

Tons of info there, will make your head spin.  ALL AX15/R15X series trans info.

Get some aspirin first!

[4bangr TJ [OP]]

Marlin, This is what I have figured so far. Get a r150f tranny from a 1996 and newer toyota, get a bellhousing from a dakota with a 2.5l and ax15 tranny. Then everything should just bolt right in. Do I need to change the clutch disk though or pilot bearing? Also can I change the gears of this tranny to 5.15. Will my 231 tcase bolt up to this tranny? 

[Marlin]

I have used the 10.5" disk that is used in the 4.3 chevy conversions.
The pilot bearing would need to be adapted as required.
Because the 5.15 trans was never made with the longer input shaft, it would not fit

The NP231 t/case will not bolt to the toyota trans.
If you have a front left diff, use the stock Tacoma t/case.

Marlin

[ccannon222]

Marlin,

Is it possible to put an R154 input shaft into a R151F trans?  If so, will that change the gear ratios of the trans?

Thanks

ccannon

[4bangr TJ [OP]]

so there is no way of getting a toyota tranny with either 4.31 or 5.15 gears in it to fit into a jeep with a 2.5L?

[Marlin]

Marlin,

Is it possible to put an R154 input shaft into a R151F trans? If so, will that change the gear ratios of the trans?

Thanks

ccannon

It is impossible to just replace the input gear only because it is so much smaller.
It is so much smaller in diameter, that it would not even touch the front constant run teeth on the factory countershaft.
To obtain the 5.15 ratio, the R452 uses the turbo first gear set, but a greater countershaft underdrive by decreasing the input gear diameter, and increasing the countershaft diameter.
This combination will effect 1,2,3,5, and reverse ratios.

[Marlin]

so there is no way of getting a toyota tranny with either 4.31 or 5.15 gears in it to fit into a jeep with a 2.5L?

The problem is that the 4.31 and 5.15 trans were only available with the short, pre 96 input shaft.
I can have inputs made to fit your 2.5 thur my importer, but the mininum order is 200 inputs!