Topic: R151 versus W56 - which gearbox behind 350 Chev?

[green200b]

Hi everyone, I own a 1982 Hilux with a 350 Chev. Currently this is fitted with a G52 gearbox and gear-driven transfer case. This is my second G52 as the first one blew up third gear, however this one is starting to make a lot of bearing noise in third and fifth, so I don't know how much longer it has.

Now I always planned on upgrading the gearbox, my initial plan was to get a W56 and fit the internals from a W58 I have sitting here, mainly to get the .785:1 fifth gear. However I am having trouble locating a forward shift W56 and I'm also wondering if this will be too much stuffing around. I want to keep my gear-driven transfer case and after doing some research have found that an R151F also has this transfer case. It also seems to be the same length and stick location as my current setup. Do people think I would be better off going for the W-series or moving up the R-series?

I don't know what strength difference there is between an R151 and an R150 but using an R150 with a transfer case adapter is also an option, just possibly a more costly one. Thanks in advance

[twistedtoy92]

R151 is stronger and has the 23 spline output shaft, also more gear options for 1st.

[green200b [OP]]

Thanks for the reply. So the R151 is stronger than the W56? How about compared to the R150? I have read conflicting reports elsewhere online but R150s are easier to find out here.

[Snowtoy]

If you go with the R151, you will have to use it's t-case, or rebuild the one you have due to the trans being 23 spline and your current t-case being 21 spine.  If you go with the R150, you will have to buy an adapter plate to bolt a 23 spline t-case to the R150 trans, or use the the R150's chain driven t-case.

As far as strength goes, the R151 was behind a 134hp/178trq engine, and the R150 was 150hp/180trq engine w/the 3.0 and the 190hp/220trq of the 3.4(254/270 w/the TRD supercharger)

If the R series transmissions were all built the same, then either one should live behind the 350, guys in the Supra community can run 400+rwhp w/no premature failures of the R154 behind a built 7mgte or 2jzgte.  You might give Marlin a call/email, and see what gears can be used in the R151 and R150, if they are interchangeable w/the R154,  the 154 has a 0.753 5th gear.

w

[green200b [OP]]

Thanks for that Snowtoy. I think I will work out the time difference and contact Marlin Crawler soon and see what they say. For ease of locating and the fact that I can't use my existing transfer case with an R151, I am now leaning towards an R150. Will talk to Marlin and see though. 0.753:1 fifth gear sounds nice though!

[84_yota_4wd]

No need to call Im here bud! 

You can use your exiting case you only need a 23 spline input gear.

You will also need that if Run a r150f But you will also need my adapter.

The biggest problem with the R151 is that they are very rare. Had to find and you will pay a pretty penny for one.

Also you no be running the bell housing anyway you will be using a adapter bell housing.

If you go with the R150 you can run our adapter on the rear to go to a gear drive case.

Long story short run what you can find, & what is cheaper as the strength is the same.