INTRODUCTION

After having had the Auto since 1991 in December 2000 I finally decided to convert it to a 5 speed manual. While I did like the auto, in some situations its widely spaced gear ratios and its nature to always drop back a gear when trying to slowly cruise in a high gear was frustrating.

The choice of a trans was difficult as besides having suitable gear ratios for the V8 the main criteria was it had to have a good overdrive. The auto had a 30% OD.

R154 TRANS

After some research I decided to use the Toyota Supra Turbo 5 speed, which is physically the same as the 4Runner V6 but it had better gear ratios and a 25% overdrive. It was also possible to increase this to 37% if required. This trans would also allow the use of the chain transfer.

Pic 1 is the R154 Supra Turbo 5 speed. Its ratios are: 1 = 3.25, 2 = 1.70, 3 = 1.30, OD = 0.75 whereas the auto is 1 = 2.804, 2 = 1.531, OD = 0.70.

Pic 2 shows the trannie now fitted with a shorter R151/R150 output shaft in order to fit the transfer. There are 2 types of transfer adapters. The one attached to the trannie is for manual selection, whereas the other is for the electrically assisted transfer (ADD) and it has both levers in the actual transfer adapter.

Pic 3 is a new electrically assisted transfer I was planning on using and the actuator can be seen attached at the rear and this is controlled by a 4WD ECU.

BELLHOUSING

I had another special bellhousing cast to mate the R154 directly to the Ford and to use a 157 tooth HO flywheel with the starter located on the right. Initially I thought I was going to have problems with clearances but it was better than the auto. I had to fabricate another sandwhich plate to suit and also got the flywheel matched balanced to my old auto flexplate, as I had previously had the engine balanced to suit this flexplate.

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Copyright © John Douglas