My R151F needs replacing... H55 or H152? (HZJ78)

[Aidan Klimenko]

Just my 2 cents after driving 70 series for 3 decades and being around many of them . I personally prefer the R151 over the H55 because I feel it shifts smoother and the gearing is spread better . I never had a R151 go out not even on the 1HDT powered rock crawler I build on 40" tires , however I have known several R151's go boom usually being in heavily overloaded cruisers doing a lot of driving on bad roads , I feel that H55's would go out just as fast for these driving conditions and had a lot of H55's already in the past that needed rebuilding .

I have 2 R151's here at the shop and one of those is going to a good friend in California for his troopy but the other is available if you want to go the used route ? It came from a 30k mile sideswiped 2016 HZJ76 that I parted out many years ago and then I put it in my crawler and added approx another 2-3 k miles on it . I can sell this one or use it in my next build .

Thanks @joekatana. If I end up going this route I'll let you know. Also, the AC kit you sold me is great! The wife is very happy.

 

[GreaseMonkeyJP]

I hear ya. I'm just having a tough time wrapping my head around replacing a gearbox that's failed twice with the same gearbox. But money talks, and the swap to the H15x definitely would be spendy.

Does anyone know of where to get these "reinforcement kits" for the R151 here stateside? If I did stick with a R, I'd love to do what I can to prolong doing this job again for as long as possible!

Marlin Crawler does have some upgrade parts for the R-series transmission. I have them in my modified R151(different 5th gear) running behind a 1HD-FT for over 120k so far with no issues. My rig doesn't weigh so much though.

 

[Aidan Klimenko]

Hey all—I’ve decided to stick with the R series and have purchased a brand new, post 2021 model from Toyota.

A few members here have mentioned that Toyota recently updated the R trans, making it hopefully stronger.

Does anyone have any insight on what was changed/improved?

The reason I ask is, I’m trying to determine if I’d benefit from installing an “upgrade kit” from Marlin Crawler or similar. Not sure if this would be redundant after Toyotas updates to the box or if the kit would provide further reliability.

Thanks!

 

[jayp2]

H55 requires a diff bell housing than the original 151 I believe.....thats another 5-600.....possibly diff clutch bits too...something to look at confirm/deny

 

[OGBeno]

H55 requires a diff bell housing than the original 151 I believe.....thats another 5-600.....possibly diff clutch bits too...something to look at confirm/deny

Requires different everything.

 

[joekatana]

Hey all—I’ve decided to stick with the R series and have purchased a brand new, post 2021 model from Toyota.

A few members here have mentioned that Toyota recently updated the R trans, making it hopefully stronger.

Does anyone have any insight on what was changed/improved?

The reason I ask is, I’m trying to determine if I’d benefit from installing an “upgrade kit” from Marlin Crawler or similar. Not sure if this would be redundant after Toyotas updates to the box or if the kit would provide further reliability.

Thanks!

I would leave it as is , I have never known anyone to put these better together then the good people at Mr T .

 

[Aidan Klimenko]

H55 requires a diff bell housing than the original 151 I believe.....thats another 5-600.....possibly diff clutch bits too...something to look at confirm/

I would leave it as is , I have never known anyone to put these better together then the good people at Mr T .

That’s what I was hoping to hear. Thanks Joe.

 

[bottombracket]

Take the new transmission, put it in the truck and run it forever. The end.

 

[Economist LC76]

Very interesting thread!
I’ve tried to check what was changed in R151F from 2007 for the LHD HZJ71.
The catalog shows that it was several R151F versions during this period. 33030-6A412 (2007-2013), 6A413 (2010-2013) and finally 33030-6A414 (2013+).
I’ve checked a difference between 2007 (6A412) and latest 2013+ (6A414). Major parts were updated (green color). I don’t know how big was a real upgrade vs just the number change, but I assume that the gearbox was heavily upgraded.
I am thinking to save some money and buy the latest R151F for my 1HZ.

 

[Aidan Klimenko]

Very interesting thread!
I’ve tried to check what was changed in R151F from 2007 for the LHD HZJ71.
The catalog shows that it was several R151F versions during this period. 33030-6A412 (2007-2013), 6A413 (2010-2013) and finally 33030-6A414 (2013+).
I’ve checked a difference between 2007 (6A412) and latest 2013+ (6A414). Major parts were updated (green color). I don’t know how big was a real upgrade vs just the number change, but I assume that the gearbox was heavily upgraded.
I am thinking to save some money and buy the latest R151F for my 1HZ.
View attachment 3781941

Wow yeah this is great. Thanks for sending!