Pzj77 1hdt swap (1 Viewer)

[noahsarrrk]

Hey how’s it going
I’ve bought a 1hdt to replace the 1pz in my 77 series and am considering my gearbox options.
Will an h151f from an 80 fit in the transmission tunnel fine? I’m assuming I will have to do some fabrication regarding the crossmembers and lengths of drive shafts?
Or has anyone used a PZ r151 behind a 1hz/hd before using the hz flywheel and clutch? or are there issues with the input shaft, bell housing etc

Cheers thanks for any advice

 

[FJ73Texas]

Take a look here although the user doesn't really seem to be active these days on mud. May be some answers you need regarding R151 behind your 1HDT

Builds - HDJ77 Build for Midwest Overlanding - https://forum.ih8mud.com/threads/hdj77-build-for-midwest-overlanding.963621/page-2

 

[rick_d]

@bottombracket

He runs a R151 behind a 1hdt. The 300mm flywheel does fit with a very minor amount of grinding to the bellhousing to clear the teeth. (I know this because I was the owner of the 74 when the engine and transmission went in).
The H15x might fit, but the shifter positions are off and neither the std forward H15x OR the rear 100 series "separated seat" H15x fit the holes in floor (tried and failed in 2009/2018 cab).

 

[joekatana]

Hey how’s it going
I’ve bought a 1hdt to replace the 1pz in my 77 series and am considering my gearbox options.
Will an h151f from an 80 fit in the transmission tunnel fine? I’m assuming I will have to do some fabrication regarding the crossmembers and lengths of drive shafts?
Or has anyone used a PZ r151 behind a 1hz/hd before using the hz flywheel and clutch? or are there issues with the input shaft, bell housing etc

Cheers thanks for any advice

1HDT will bolt right up to your 1PZ R151 trans , you can use either 275mm 0r 300 mm flywheel as the physical dimensions between the 2 are the same only the machined surface is different , I have run R151's behind 1HZ , HDT and HDT FT engines and prefer the shifting from a R151 over a H55

 

[bottombracket]

The simple answer is just to run whatever transmission you have in there right now. If it’s an R151, you can just bolt it right up to a 275/21 spine clutch, though I might upgrade to a heavy duty clutch setup if your right foot is heavy. If you want to run a 300 mm flywheel, you will need this Exedy ISD136U 21 spline/300 mm clutch which will work just fine.

If you want to run an H15X transmission, you will need a lot more parts and need to do some fabrication. The transmission hump cover from a ViDJ79 should fit. The HDJ79 cover is no longer available. You’ll need VDJ/HDJ floor mats to make your shifter holes in the flooring line up. The VDJ crossmember as well as frame to crossmember mounts are readily available from multiple sources.

If you switch to an H15X transmission, you will most likely want to run an HF1A t case. If you do that, you will either need to find one used (ping me I can help) or buy new and assemble the shifter new from parts. Stedman can help you with that.

Simple answer: run what ya got behind the 1PZ now.

 

[noahsarrrk]

The simple answer is just to run whatever transmission you have in there right now. If it’s an R151, you can just bolt it right up to a 275/21 spine clutch, though I might upgrade to a heavy duty clutch setup if your right foot is heavy. If you want to run a 300 mm flywheel, you will need this Exedy ISD136U 21 spline/300 mm clutch which will work just fine.

View attachment 3492178

If you want to run an H15X transmission, you will need a lot more parts and need to do some fabrication. The transmission hump cover from a ViDJ79 should fit. The HDJ79 cover is no longer available. You’ll need VDJ/HDJ floor mats to make your shifter holes in the flooring line up. The VDJ crossmember as well as frame to crossmember mounts are readily available from multiple sources.

If you switch to an H15X transmission, you will most likely want to run an HF1A t case. If you do that, you will either need to find one used (ping me I can help) or buy new and assemble the shifter new from parts. Stedman can help you with that.

Simple answer: run what ya got behind the 1PZ now.

View attachment 3492192

Cheers, sounds like I’ll stick with the r151 at this stage then. I’ve heard that the input shaft or the bell housing length is different on the r151 behind a 1PZ in comparison to 1HZ r151? Or is this incorrect?

 

[Rigster]

Cheers, sounds like I’ll stick with the r151 at this stage then.

This is by far the most cost and time effective. Did you happen to get the flywheel from the donor engine? If so, use that and get a stock clutch. Otherwise you will eventually start seeing slippage with a stock 275mm flywheel. I am generating around 200HP on my turboed 1HZ and it was slipping every time I really pressed the right pedal down in 4th and 5th gears, then eventually 3rd.... you get the idea.

I went with the 4Terrain HD clutch out of Australia (Brett's Truck parts had the best deal) specifically made for the 1HZ 275mm flywheel, and it has so far put in over 10,000kms, some of that pulling a trailer without error. What is your driving style? If you are not hard-wheeling, hard shifting, hard on your machine, the R151F should do just fine behind a more powerful power plant. There are also shops that have kits to "fix" some of the weaker points of the gearbox that you can take advantage of if/when you need to rebuild.

Sorry, I cannot be of more assistance with the length of the input shaft between 1PZ and 1HZ. @OGBeno may know off the top of his head. Best of luck with the conversion, this should be a wonderful upgrade.

 

[noahsarrrk]

This is by far the most cost and time effective. Did you happen to get the flywheel from the donor engine? If so, use that and get a stock clutch. Otherwise you will eventually start seeing slippage with a stock 275mm flywheel. I am generating around 200HP on my turboed 1HZ and it was slipping every time I really pressed the right pedal down in 4th and 5th gears, then eventually 3rd.... you get the idea.

I went with the 4Terrain HD clutch out of Australia (Brett's Truck parts had the best deal) specifically made for the 1HZ 275mm flywheel, and it has so far put in over 10,000kms, some of that pulling a trailer without error. What is your driving style? If you are not hard-wheeling, hard shifting, hard on your machine, the R151F should do just fine behind a more powerful power plant. There are also shops that have kits to "fix" some of the weaker points of the gearbox that you can take advantage of if/when you need to rebuild.

Sorry, I cannot be of more assistance with the length of the input shaft between 1PZ and 1HZ. @OGBeno may know off the top of his head. Best of luck with the conversion, this should be a wonderful upgrade.

I haven’t got a flywheel yet as the motor came out of an auto 80. Sounds like I’ll try get the 300mm flywheel and if not get a heavy duty clutch with the 275. Not planning on anything too hard on the vehicle just a touring set up and a bit of towing every now and then.
Cheers bro

 

[bottombracket]

300mm flywheel 13405-17020
Locating dowels x2 90250-10192
Flywheel bolts x8 90105-12169

There are a couple of threads out there on having a competent machine shop redrill a 275 to 300, as the flywheels are dimensionally the same. @gifu was in the stages of active contemplation as 275s are all over the place and a new 300mm is $450 plus shipping from someplace likely far, far away.

 

[RandyMarsh88]

This is all good info. I’m going down the same path and I’m not sure what the tranny of choice will be. I see a lot of hate for the r151f out there, but mine feels great with 200k behind a 1pz. I’m leaning towards putting heavy duty parts in my existing r151, but I dunno. Let me know if your r151 mates up nicely with the 1hd-t. I’ll let you Guinea pig it for me haha