H151 Transmission (5 Viewers)

[Radd Cruisers]

volcano, if the motor/box package is from a australian 79x then the box is a R151 NOT A H151

the R151 is a smaller weaker box again

the H151 is a really strong box we have them behind the new V8 desils in OZ

to answer the ??? yes i went through 3 H55 boxs behind my 1hdt and my now 1hdft
the first box had 120 000 klms, had it rebuilt lasted 25 000 klm blew up again and thirdly went again, the problem the bottom bearing in the box cannot handle the tourque these 1hd motors produce and simply let go

apon putting a H150 (same box as a H151 but different first gear) i have not had a drama

the h150 is factory behind our standard 80x and people never have a prroblem with these gearboxs except the early sincros

the h55 is a strong box is re reced about 150 000 klms and looked after but the h150/h151 is the pick of the 5 speeds

any questions or queries just ask

i get the impression people are mixing the R box with the H box

with the 79x with the R151 we are having a lot of problems with the at about 120 000 - 150 000 klm as they cannot handle the work and simply are to small a box for a big vehicle

Great information, thanks for sharing.

Rob

 

[Kroll]

Oh and of course never pull start your 12h-t with an H55F....NO MATTER WHAT!
Just thinking about a customer from last summer who had dead batteries in his 24v HJ61. Turns out the tow truck driver decided it was a good idea to pull start the cruiser! Turned out that the tranny suffered the consequences of that decision. Sometimes I wonder about people.
Cheers.

 

[SimonInAustralia]

Since the 1HZ and drive train came out of a 2001 HZJ78 it sounds like the 1HZ is mated to an H151.

The 78 series had gearbox (R151F) problems up until about 2002.

The gearbox has a 2 piece output shaft, which ends up shearing off splines and leaving you stranded.

The design was fixed, I think in late 2002 from memory, and you can/should repair it if broken (or as a preventative measure) with a replacement/stronger single piece output shaft.

You might want to check exactly what the ratios in the box are, as I think they might be different in the HZJ78 to the HZJ75, with a different diff ratio, so not all 1HZ/gearbox combinations have the same gearbox ratios.

 

[Volcano cruiser]

The 78 series had gearbox (R151F) problems up until about 2002.

The gearbox has a 2 piece output shaft, which ends up shearing off splines and leaving you stranded.

The design was fixed, I think in late 2002 from memory, and you can/should repair it if broken (or as a preventative measure) with a replacement/stronger single piece output shaft.

You might want to check exactly what the ratios in the box are, as I think they might be different in the HZJ78 to the HZJ75, with a different diff ratio, so not all 1HZ/gearbox combinations have the same gearbox ratios.

Simon,
Thanks for the info, very useful. Per the purchasing agent all of the package, engine, transmission and transfer case were all in working order before being crated up.
Now as to the R151F, two piece output shaft, shearing off splines, leaving you stranded, gotta find/buy a replacement output shaft for this thing somewhere here in Central America???WTF. I pray to God that that is not what is hooked to my new stuff. In that connection do you know where I need to look to see any identifying serial number etc fo the transmission. At least I will then know where to look and figure out what it is that I have.
Thanks,
John

 

[SimonInAustralia]

Simon,
Thanks for the info, very useful. Per the purchasing agent all of the package, engine, transmission and transfer case were all in working order before being crated up.
Now as to the R151F, two piece output shaft, shearing off splines, leaving you stranded, gotta find/buy a replacement output shaft for this thing somewhere here in Central America???WTF. I pray to God that that is not what is hooked to my new stuff. In that connection do you know where I need to look to see any identifying serial number etc fo the transmission. At least I will then know where to look and figure out what it is that I have.
Thanks,
John

Not sure how to work out whether that transmission will have the problem or not, other than opening it up and looking at it.

If it had the problem when it was in the last truck, it may have been replaced already. If it has been replaced, I don't think there is anything externally visible to let you know it has been replaced or not.

I think it was up until sometime in 2003 that they had problems, but not really sure of the exact cutoff date, before the factory started using single piece output shafts, but you might want to search this forum, and the web in general, to find some discussion on it.


This is a post I made to another forum regarding the weak output shaft...

I called up the rental company that sold me my 78 troopy to ask about the output shaft solution they use on their 78 series rental trucks.

They rebuild their gearboxes with a stronger output shaft, along with some sort of change to 5th gear that they didn't provide details on, and all other necessary components.

They purchase their stronger output shafts from a company called Don Kyatt in Melbourne.

I called Don Kyatt, they confirmed that they do sell a stronger input/output shaft kit for the 78 troopy, priced at $538.30(Australian) inc GST.

This apparently is just the shaft(s?) themselves, and no extra bits that you would need for the rebuild.

I asked if I should order one as a spare, he said there were plenty, and would be avilable well into the future.

He also said that as my gearbox already has the stronger shaft from them, that it should be fine, and not break in the future like the standard ones.

So, there is one possible solution, but no idea how well it fixes the problem, though it seems fine on my truck I haven't pushed it hard, and with something like that I suppose you wouldn't know until it actually broke.

There is another thread on that forum discussing it specifically...
Early 78 Gearbox Internal Spline Wear/Strip Problems? - Australian 4WD Action Online Forums - the 4WD, 4x4 and offroad truck community. Get the latest tips, news, reviews, images and video clips.


One guy on that forum had his break, this is a PM he sent to me in which he discusses it...

...drove to Bathurst n Sydney via Cairns. All the time worried about the g'box (now making an awfull clunk as the drive takes up slack) . I got back as far as townsville and BANG...STOP.. F#*K... G'box grind. but no power to wheels.
Great timing??.... lucky, in town... not so lucky, floods have vehicle on a truck stuck in Mt Isa.
Rebuilt/upgraded box from perth is here in Darwin waiting to fit...... I will try to get some info on improved parts over the next week.

A company in germany sells a replacement shaft kit, and this a Babelfish german-english translation of their catalog information on the replacement kit...

Left down: That is the famous-notorious connecting shaft from the transmission to the transfer case of all HZJ71,74,78 and 79. Who heard still nothing of it: Despite the use of a new, improved transmission one probably improvised something with the connection to the transfer case. Both parts are connected by the sleeve (left in the picture) by means of a relatively fine teeth. On the gearbox side this is correct, since the sleeve rises up rather far on the transmission output wave. On the rear side, thus to the transfer case wave the sleeve seizes however only on a length of approx. 18mm (!). Since from here from whole Kraft of the engine over the transmission to the rear and/or foremost and rear axle will transfer, it came already several times, straight with area employments and sudden changes of load, to breaks. Afterwards moves no more wheel and a repair on the way is, even if one carries all parts forward as a precaution, much aufwändig, if not even impossible. Since this problem admits also to the manufacturer is, for approx. autumn 2003 a one-piece stronger wave than spare part for this two-piece wave is already supplied and/or blocked with all newer models. We recommend to exchange the wave as a precaution before a longer journey straight into remote areas. The work is however something for the experienced nut runner and a lifting platform or pit should for the order. We offer the complete reequipping kits with all necessary seals, camps, shaft seals and new Locknuts (illustrated as above) for € 375.00 on. The wave alone costs € 188.50 and one must even decide whether one " alten" Camp and shaft seals (ever 2 pieces, approx. € 155.00) continue to use and possibly later once again everything apart-built. With a very new vehicle this can surely make for sense. We have after approximately. 80.000km run achievement rather directly everything changed. Absolutely necessarily however the 2 locknuts are, 5 Paper gaskets and 1 O-ring (€ 38.00). With a vehicle with a run achievement of approx. 140.000km the wave was short vorm cutting (S. picture down center and right). For using the new seals a high temperature-steady silicone sealing compound is absolute necessarily.

...thier catalog can be found here (in German), the 3rd link down for just the HZJ gear, or the first link for the full catalog...
Tourfactory - Der Katalog

 

[Snailtrail]

Hey Volcano, are these pictures you posted in another thread actually of the 1HZ/gearbox you have purchased??

If so, im sure someone can tell whether or not the box is a R series or H series.

Any takers.....

 

[Clint79]

Not sure if this makes a diff between the r and h box's but in the aus hzj79's ive been in which would have the r151 box i spose (do they ?) the 4wd shifter is h2 pull down for h4 n then across to the right side of the vehicle for L4. My aus fzj79 which has the h151 box(i think ive worked out ??) is h2 pull down for h4 down for n down for L4 . The Main gear shifter in the sits closer to the hand brake lever in the hzj 79 compared to my fzj79 being closer the under dash air vent pipes like the older h55f

 

[Volcano cruiser]

Not sure how to work out whether that transmission will have the problem or not, other than opening it up and looking at it.

If it had the problem when it was in the last truck, it may have been replaced already. If it has been replaced, I don't think there is anything externally visible to let you know it has been replaced or not.

I think it was up until sometime in 2003 that they had problems, but not really sure of the exact cutoff date, before the factory started using single piece output shafts, but you might want to search this forum, and the web in general, to find some discussion on it.


This is a post I made to another forum regarding the weak output shaft...



There is another thread on that forum discussing it specifically...
Early 78 Gearbox Internal Spline Wear/Strip Problems? - Australian 4WD Action Online Forums - the 4WD, 4x4 and offroad truck community. Get the latest tips, news, reviews, images and video clips.


One guy on that forum had his break, this is a PM he sent to me in which he discusses it...



A company in germany sells a replacement shaft kit, and this a Babelfish german-english translation of their catalog information on the replacement kit...


...thier catalog can be found here (in German), the 3rd link down for just the HZJ gear, or the first link for the full catalog...
Tourfactory - Der Katalog

Simon,
This is really great information even though it is scary as hell. I just really hope that none of it applies to me, i.e., that I have the h151 and not he r...
Thanks,
John

 

[Volcano cruiser]

Hey Volcano, are these pictures you posted in another thread actually of the 1HZ/gearbox you have purchased??

If so, im sure someone can tell whether or not the box is a R series or H series.

Any takers.....

Yes, this is what I bought and is on the way. If anyone can id the transmission from these that would be a big help. Failing that I'm looking for where markings would be found on the outer case of the transmission which would tell me IF I need to tear into it to see if it is in fact the R ( with the problems) v. the H (without the problems)
Thanks,
John

 

[crushers]

which bearing let go?
25,000 km says either poor rebuild or poor parts used to me.

but if you don't like the H55F that is fine. personally i do not like the shifting of the H150/H151 boxes. each to their own.

as for the splines tearing out, i chatted the other day with the mine supplier about the R151/R141 trannies and he was saying the only issues they have been having is reverse. the reverse can not stand up to the abuse of the mine operators.

to answer the ??? yes i went through 3 H55 boxs behind my 1hdt and my now 1hdft
the first box had 120 000 klms, had it rebuilt lasted 25 000 klm blew up again and thirdly went again, the problem the bottom bearing in the box cannot handle the tourque these 1hd motors produce and simply let go

 

[gilghana]

We have had problems on 2007 HZJ79s with the R151 g/box - IIRC both broke thrust washers, but as far as we could tell this was from serious abuse in 5th gear with BIG loads in the back. The drivers drive them like they stole them. Day in day out only off road with really large loads - massive diesel welding set plus oxy and acetylene full size bottles, plus tools, plus say a D8 lift cylinder plus 4 guys.
On the other hand we have about 8 or so HZJ105s with the same box. Not one has had a single issue. They do big miles all the time, mix of roads and normally 4 or 5 people plus luggage. Again, they are driven hard. Not heavy duty wheeling, but certainly not mall runs!
I reckon they are tough enough but just not as tough as they could be. I drove a 105 home tonight after mine got banged a bit and this vehicle has 180,000kms on it - shifts superbly and still feels quite fresh in general. Especially in a lighter 40 series I wouldn't be over concerned.

 

[roscoFJ73]

as for the splines tearing out, i chatted the other day with the mine supplier about the R151/R141 trannies and he was saying the only issues they have been having is reverse. the reverse can not stand up to the abuse of the mine operators.

A local gearbox and diff rebuuilder who does a lot of work for mining has dozens of R151 go through his workshop on a monthly basis.
Not only the shaft causes problems,but the synchroes and bearings(and reverse) also have an early life.

The box is derived from a Supra and simply not up to the punishment the larger landcruiser engines can dish out.
It is a physically a smaller and lighter gearbox and therefore has less metal than its predecessor
Toyota installed them as a weight and friction saving measure to improve the economy of the 78/79 series.

 

[bsmith123]

thread revival

waking this thread up with a question

will a h55 bolt up to a 1HDT?
if so what year/model do I need to pull it from?

do I need the 1hdt bell housing clutch flywheel?

does someone make an adapter or do I even need one?

anyone seen a link on a 1hdt into a 40?

I have a chance to get a 1hdt really reasnoable from a wrecked 98 80 series.

I understand the 151 gearbox is too long for my 71 FJ40 but with a 55 it should fit?
https://forum.ih8mud.com/diesel-tech-24-volts-systems/245813-1hz-install-into-1978-fj40.html

this guy put a 1hz in his 40 but does not mention the gearbox/xfer case


Appreciate any help or info

 

[70sguy]

Yes, it will bolt up. See pic.
You need the H55F and Bellhousing off a 1HZ (HZJ7) as well as the backing plate.
As far as the clutch goes it depends on what you can get your hands on for a flywheel.
If you get a 300mm surface HDJ81 MTM flywheel then you need to
go the Isuzu 300mm fine spline center Clutch disc with HDJ80 300mm pressure plate.
If you end up with the 275mm surface 1HZ flywheel you can go with factory 1HZ disc and PP, or
to make up for less friction surface, go with an Exedy Safari tough 1HZ kit for the extra clamping force.

I may be forgetting something.. but that's the big stuff.

This has been discussed a fair bit here, do a search and you will find.

 

[Volcano cruiser]

Yes, it will bolt up. See pic.
You need the H55F and Bellhousing off a 1HZ (HZJ7) as well as the backing plate.
As far as the clutch goes it depends on what you can get your hands on for a flywheel.
If you get a 300mm surface HDJ81 MTM flywheel then you need to
go the Isuzu 300mm fine spline center Clutch disc with HDJ80 300mm pressure plate.
If you end up with the 275mm surface 1HZ flywheel you can go with factory 1HZ disc and PP, or
to make up for less friction surface, go with an Exedy Safari tough 1HZ kit for the extra clamping force.

I may be forgetting something.. but that's the big stuff.

This has been discussed a fair bit here, do a search and you will find.

There it is, look at the pretty baby! B, compare the pics of what I had above, the H151 and the H55, look at the difference in length and shifter positions, etc.

 

[70sguy]

Ya.. if you try and put the H55F behind a 1HD-T in an 80 series, the shifter comes up nearly under the dash. Better in a 40/60/70.

 

[american psycho]

H55F also came in the BJ42 1983 and 84

the h55f also came on the 1997 hzj73 i just bought.

 

[bsmith123]

nice

nice looking motor!, the details of what clutch to use etc are just what I need

what about the the clutch actuation in the 40?

would I need to cobble up a bracket for the slave cylinder or is it a whole different set up?

 

[lshobie]

I just rebuilt the R151 in my HZj79, it had about 4200 hours of mine use and 400 hrs use with a turbo running 15 pounds on it. The tranny was making the typical r151 "clicking" sound after many kms, never rebuilt, synchros just starting to get sloppy in second.

I took the box apart and found that 1st and 5th gears were showing heavy pitting, almost like cavitation or delamination of the surface of the gears, the bearings seemed fine. It had the output shaft with the spacer as well. I bought the single piece shaft from Oz and installed it, installed new bearings and shafts with gears from a donor box, I also installed a new bearing retainer from Marlin crawlers that is much heavier than the stock r151 type, Marlin says that one of the main problems with that box is the retainer on the main shaft loosens and allows the whole gearset to move excessively - causing bearing and gear wear. Also, using the correct "c" retainers is very important, they have to be so tight, if loose at all when reinstalling the box will not last long.

Marlin makes r151's that he uses in trucks with over 1000hp and doesnt have "problems". I would have liked to put an H151 in my truck but opted to rebuild the r151 because I had most of the parts and wanted to try a rebuild. It's back in my truck and it is so tight and shifts very well. The H55F is great, some say "bulletproof" but I'll call bull**** on that from experience, it'll mate to the 1hdt but since it really wasn't tested on the 1HDT I wouldn't be surprised if it couldn't take it. Certain engines put different forces on transmissions = some just weren't designed to handle characteristics of particular engines. I can take or leave the h55f.

The r151 can be installed and removed by one person pretty easily compared to the h55f, and, it can be rebuilt in a few short hours, I think it weighs in at about 85 pounds. It'll be interesting to see how it hold up to the rebuild and 15 pounds.

As discussed earlier from my research I found that the only real problems with the H151 was from 91-93 and it was a synchro issue.

 

[70sguy]

nice looking motor!, the details of what clutch to use etc are just what I need

what about the the clutch actuation in the 40?

would I need to cobble up a bracket for the slave cylinder or is it a whole different set up?

No bracket required for the slave. The mount is cast right into the 5spd 1HZ bellhousing.
Not sure what the 40 has for clutch pedal/master set up, boosted or not? But I think worse case you
may need to bend custom length line and get a piece of soft line in the correct length.
Minor issues methinks.