Just to weigh in...
When we swapped a 1HD-T into what had been a 1HZ 105 we did not change the transmission from the original R151F other than to put in the Terrain Tamer taller 5th. It shifted nicely and I told myself that I was not pushing the truck hard enough to be a problem. Well I was doing a Ramadan Iftar out in the sand and got stuck and was cranking it pretty hard. It survived and I got out of the desert but it started popping out of 1st very regularly. Turned out I had broken the large spacer washer in front of 1st gear into four pieces. The transmission still 'worked' but you had to baby it.
I decided that it did in fact need an H series transmission for that 1HD-T, but I needed some time to figure out what to do and where to get it from. So we put in another R151 that was sitting around from another diesel 105 project and I am running on that now. It pops out of 5th occasionally.
What I finally did was contact a couple of AUS suppliers and found one that does a lot of R to H transmission conversions on 105s and asked them to build and supply a new transmission for the 105. They start with a new H-series transmission and then get an old casting for the rear mount shifter portion that was used on the standard gas 100 series trucks. I'm awaiting that new transmission now.
And on a troopy where we did a gas to diesel conversion we kept the original H-series transmission and just changed the bell housing (available new from Toyota) and the input shaft I think. The troopy shifts very nicely on that H series transmission. The 1HZ in the troopy has a Safari mild turbo in it so the H series gives me some piece of mind.
Finally, on the latest HZJ79 pickup project, I am staying with the normally aspirated 1HZ. The truck came with an R151 and I am staying with that albeit with the taller 5th gear from Terrain Tamer.
When we swapped a 1HD-T into what had been a 1HZ 105 we did not change the transmission from the original R151F other than to put in the Terrain Tamer taller 5th. It shifted nicely and I told myself that I was not pushing the truck hard enough to be a problem. Well I was doing a Ramadan Iftar out in the sand and got stuck and was cranking it pretty hard. It survived and I got out of the desert but it started popping out of 1st very regularly. Turned out I had broken the large spacer washer in front of 1st gear into four pieces. The transmission still 'worked' but you had to baby it.
I decided that it did in fact need an H series transmission for that 1HD-T, but I needed some time to figure out what to do and where to get it from. So we put in another R151 that was sitting around from another diesel 105 project and I am running on that now. It pops out of 5th occasionally.
What I finally did was contact a couple of AUS suppliers and found one that does a lot of R to H transmission conversions on 105s and asked them to build and supply a new transmission for the 105. They start with a new H-series transmission and then get an old casting for the rear mount shifter portion that was used on the standard gas 100 series trucks. I'm awaiting that new transmission now.
And on a troopy where we did a gas to diesel conversion we kept the original H-series transmission and just changed the bell housing (available new from Toyota) and the input shaft I think. The troopy shifts very nicely on that H series transmission. The 1HZ in the troopy has a Safari mild turbo in it so the H series gives me some piece of mind.
Finally, on the latest HZJ79 pickup project, I am staying with the normally aspirated 1HZ. The truck came with an R151 and I am staying with that albeit with the taller 5th gear from Terrain Tamer.
