H151F Rebuild (2 Viewers)

[DivByZero]

One very important thing of note - I think I've found a way to accurately identify the production date of these gearboxes from the outside. There is a code stamped on the front bearing retainer:

You can see the code stamped on the bottom of the bearing retainer. On my pre-92 box, it reads 142. On the reported 97 model box, it's 787. That suggests to me the first number is probably year of manufacture. Hey @OGBeno, do you know of any three code date format Toyota stamps on parts? It'd be handy to be able to confirm week, or at least month of manufacture by looking at the outside of these boxes alone.

 

[DivByZero]

Quick update. Before doing any work on the internals, I decided to get a new bench vice with a swivel base so I could rotate the gear assembly while I had it mounted. That arrived a few days ago, so I used some time this weekend to anchor it to my workbench, and I then used a couple of bolts as per the FSM and mounted the gear assembly by the intermediate plate:

I'm not in any rush, still got bearings slowly coming from a few different sources, so I'll be taking my time and playing around with this box for awhile. I'll try and document the differences between the part revisions as I go, and I'm going to have a close look at compatibility to work out what the rules are for swapping things around between revisions.

 

[ArmyFJ]

Well done! Looks like you are well on your way. Love all the great info you are posting for the community.

 

[DivByZero]

I've been taking some time to research and study the design of the H150F/H151F gearboxes, and have a close look at the specific changes that occurred over the model years. My goal here is to better understand the advantages and disadvantages of each change, so I can determine what the "best" version of this box would be, and build my own up to that spec.

First of all, some fundamentals. It's impossible to evaluate these transmissions without understanding the physics of how they operate, and the engineering principles behind them. I strongly recommend watching this short 3 minute video, which gives a great visual primer:

And optionally watch this longer one for a real-world example and some info about wear:

And if you want to get really nerdy, here's a journal paper which goes into some more detail:

https://www.ijtsrd.com/papers/ijtsrd38370.pdf

For reference below, here's a simple named overview of a pair of gears synchronized by a single blocker/synchro ring between the hub and each gear, with the same design Toyota used in the H150/H151:

To break things down significantly, IMO the best revisions of these boxes are manufactured from 1992/08 to 1996/08. I'll explain why.

In the beginning, all the the hub sleeves in the H150/H151F had symmetrical, straight feed dog teeth, like this:

The same is true for the teeth on the synchro/blocker rings, and the teeth on the synchroniser cone attached to the gear. This is the classical design for this kind of synchro going back 100 years, and all H150/H151 gears used it in the first iteration in 1990/01.

In 1992/08 Toyota engineers made a tweak. You see, symmetrical teeth give the same experience shifting up or down, or in other words, when the gears needs to be slowed down to match the output shaft (shifting up, say from 1st to 2nd), and the opposite when the gears need to be sped up (IE, shifting down from 2nd to 1st). This isn't what's needed in practice though. In reality, people can, and do, shift straight from 1st to 2nd very quickly with just a flick, to get quick acceleration, and to a lesser degree from 2nd to 3rd. In reality people don't downshift as quickly or as often. Due to gearing as well, the lower gears need to deal with a much bigger mismatch of rotational speeds than the higher gears, because the difference in ratios is more extreme.

I suspect the first gen gearboxes were more prone to grinding gears on very quick shifts, which occurs when the synchro/blocker ring fails to match the gear speed to the hub speed quickly enough, and also fails to "block" the shift sleeve from passing the teeth on the synchro and allows it to grind against the teeth on the synchroniser cone attached to the gear. To address this Toyota tweaked just the 2nd and 3rd gears, adding an angle offset to the teeth on the hub sleeve facing 2nd and 3rd, and the corresponding teeth on the synchro rings and the gears for 2nd and third, like this:

This angle change improved two things. Firstly, the angle reduced the depth of the teeth on the blocker/synchro ring, giving more time for pre-synchronisation to occur prior to teeth contact, which would reduce wear over time due to less blocking action. Secondly, the more aggressive angle gave a stronger blocking action on upshift, greatly reducing the chances of grinding occurring on upshift, at the expense of slightly weaker blocking action on downshift, which is a good trade-off for how people typically shift the gears. All in all, this was definitely an improvement.

Toyota also made a change on the H150F box in 1992/08, going from a single synchro ring to a triple ring setup, like this:

The three peice rings are better. The way they work is the steel ring in the middle locks into grooves cut into the synchroniser cone attached to the gear, so that it moves with it. This increases the surface area for the synchro rings to operate on, as instead of just the outside surface of the synchroniser cone mounted to the gear, you can now brake against the inside and outside of the steel ring too, roughly tripling your braking power. The H151 came with triple synchros on 1st, 2nd and 3rd from the start. The H150 added it for 2nd, and 2nd only, in 1992.

From here, the boxes stayed the same effectively, until 1996/08. What happened at this point, is that Toyota started making the boxes cheaper to manufacture, but not better. Worse in fact, and it started with what they did to the gears. This was due to tech changes from the 90 series "light duty" Landcruiser Prado, which had been released just 3 months prior, and an understandable desire from Toyota to consolidate their production processes.

First of all, understand that the gears in the H150/H151 are not a single peice. They're technically a gear assembly, consisting of the gear itself, and the synchroniser cone pressed onto the gear. You can separate them, like I've done here for the 5th gear using a press:

This two peice design is the traditional way to do it, and other manufacturers sometimes offer the synchroniser cones as a separately orderable part, which makes sense, since very often your gears themselves are immaculate after a decade or more, while your synchroniser cone may be glazed or grooved, and the teeth worn. Toyota don't offer this part separately unfortunately, but they are manufactured separately. In an attempt to reduce costs and consolidate production, they brought over a machining change from the Prado line about how they made these synchro cones. Earlier versions looked like this:

If you look, you'll see they appear to be forged, and they have an inset, reducing weight and allowing for a deeper cone with more friction area. With the developments on the prado though, Toyota wanted to simplify the machining of the synchro cones and the synchro rings, so they changed the cone design to this:

If you look closely, you'll see the significant differences with the synchroniser cone. While the original had a recessed top surface above the dog teeth, this one has a flat surface. The cone itself is also shallower, with a corresponding loss of depth in the synchroniser rings that fit with it. Although the cone itself is very slightly a wider diameter, there's still a net loss of surface area. The manufacturing process also appears to have changed, switching from a forged part to a cast part, reducing costs, but also lowering the strength of the material, which will lead to it wearing more quickly. Basically, it's a loss all around.

Toyota didn't stop there though. Shortly afterwards, they also revised the 1st and reverse gears, switching from separate gear and synchroniser cones to a single-piece (cast?) gear with an integrated synchroniser cone, like this:

This reduces costs for Toyota, going from a 5 step process involving two separate pieces that need to be formed, tooled, and then combined, to a 2 step process with one piece. There are no mechanical advantages to this though, quite the opposite. It's now impossible to swap or replace the gear and synchroniser cone separately. Additionally, there was a recess with void space between the two in the two piece design, which reduced weight. The single piece gears are heavier, increasing the load on all the synchroniser rings, effectively making the synchro rings wear faster and become less effective.

They also made changes to some of the hub sleeves, cutting away some of the teeth to consolidate parts/tooling to with their new Prado gearboxes, which had a tweak to the way the synchro rings interlocked with the hubs. You can see the missing teeth here:

There should be three cutaways with a tooth in the middle for the hub keys, but in this design there are six, with an extra 9 teeth removed from the sleeve. This offers no advantages to the H150/H151, especially because the synchro rings didn't even change to match the sleeve change, so there's simply less tooth engagement, as you can see here if you look closely:

Since the teeth on the hub sleeve are the only thing that transfers power from the gear to the output shaft, removing these teeth makes the box weaker, and puts more load on the remaining teeth, accelerating wear. It's a loss all round.

The same is true of all other changes to the original H150/H151 boxes for the 80 series, there are no benefits to any of the later changes around the shifting system, its all about tooling and parts consolidation towards the end of 80 series production.

In terms of parts interchange, there are actually a lot of options. The rules are basically this - if you're switching from a single synchro to a triple synchro, you need to switch the synchro cones. If you're switching between straight and angled feed dogs, you need to switch the synchro cones, rings, and hub sleeves.

The "ideal" thing for a 1HZ if you want to keep the shorter 1st gear ratio, is to take a H151F from 1992/08 - 1996/07, and use a press to remove the triple synchro cone from the taller 1st gear in the H151 and press it on the gear from the H150. You can then swap the counter gear, 2nd gear and and the input shaft from the H150 to the H151, or you can swap the 3rd and 2nd gears and synchros from the H151 into the H150. That gives you triple synchros on the first three gears.

Anyway, I'll leave this post here for now. I've got more to write about the revisions of this box in later Landcruisers, such as the H152 in the 70 series, and related changes in synchros, and quite a bit to write about bearings. I'll post that info sometime soon.

 

[DivByZero]

Here's a bit of a reference table for what changed with gear part numbers, why, when, and for what versions of the gearbox. I'll add pictures as I can/find them:

1st Gear	Part No	Picture	Notes
H150F 1990/01 - 1996/09	33032-60010		-Straight feed dogs
H150F 1996/09 -	33335-60110 [BC]		-Cost-cutting single piece cast
H151F 1990/01 - 1996/09	33032-60020		-Triple synchro cutouts
H151F 1996/09 - 1996/10	33032-60090		-Cost-cutting shorter synchro
H151F 1996/10 -	33335-60100 [BC]		-Cost-cutting single piece cast

2nd Gear	Part No	Picture	Notes
H150F 1990/01 - 1992/08	33033-60010		-Straight feed dogs
H150F 1992/08 - 1996/08	33033-60011		-Angled feed dogs -Triple synchro cutouts
H150F 1996/08 -	33033-60060		-Cost-cutting shorter synchro
H151F 1990/01 - 1992/08	33033-60020		-Straight feed dogs -Triple synchro cutouts
H151F 1992/08 - 1996/08	33033-60021 [BC]		-Angled feed dogs
H151F 1996/08 -	33033-60070		-Cost-cutting shorter synchro

3rd Gear	Part No	Picture	Notes
H150F 1990/01 - 1992/08	33034-60010		-Straight feed dogs
H150F 1992/08 - 1996/08	33034-60011		-Angled feed dogs
H151F 1990/01 - 1992/08	33034-60020		-Straight feed dogs -Triple synchro cutouts
H151F 1992/08 - 1996/08	33034-60021 [BC]		-Angled feed dogs
H151F 1996/08 -	33034-60050		-Cost-cutting shorter synchro

5th Gear	Part No	Picture	Notes
H150F/H151F 1990/01 -	33036-60010		-Straight feed dogs

Reverse Gear	Part No	Picture	Notes
H150F/H151F 1990/01 - 1996/09	33031-60010		-Straight feed dogs
H150F/H151F 1996/09 -	33331-60050 [BC]		-Cost-cutting single piece cast

 

[DivByZero]

An update now about bearings. I couldn't find this info anywhere online, so I hope it helps other people.

I'm going to start with the needle roller bearings which support the gears in the gearbox. These are the same for all 80 series H150/H151 boxes, because they share the same output shaft. Here's a table

	Toyota P/N	Manufacturer	Manufacturer P/N	Dimensions (IDxODxD)	Notes
1st Gear	90364-50001	Koyo	RP505734A	50x57x33.5mm	Steel Cage
2nd Gear	90364-58003	Koyo	58RFN6537A	58x65x36.6mm	Polyamide Cage
3rd Gear	90364-38017	Koyo	RP384440A	38x44x39.8mm	Steel Cage
5th Gear	90364-46005	Koyo	RPU465343A	46x53x42.6mm	Steel Cage
Reverse Gear	90364-44003	Koyo	RP455236A	44.5x51.5x36mm	Steel Cage
Reverse Idler Gear	90364-28010	NSK?	283544Z	28x35x44mm	Steel Cage, double row

And here's the Koyo needle roller bearing catalog info:

https://koyo.jtekt.co.jp/en/support/catalog-download/uploads/catbs007en.pdf

This is very useful info. The going rate for a bearing kit seems to be about $1000AUD. I got two sets of genuine bearings for about half that number, because I was able to shop around. Well worth doing.

Now, something might jump out from this table. If not, it'll certainly jump out when you get your bearings. All these needle roller bearings are in steel cages, like this:

All except one that is. The 2nd gear comes in a polymer (plastic) cage:

Yuck. Plastic doesn't belong in drivetrain components IMO. At first I thought maybe Toyota had changed the part, that maybe originally it was in a steel cage too, but they switched it out for plastic later and kept the same part number. That kind of thing has happened with other parts, they can change the design and keep the part number if it remains functionally equivalent. Doing some searching though, all the boxes I saw had plastic bearings from the factory, and when I checked the "New Car Features" manual for the 80 series, I found an illustration which confirmed for me the part always had a plastic cage.

I wasn't happy with this. Why? Well needle roller bearings have three typical cage materials, brass, steel, and polyamide, in that order of which is "better". Brass bearings are often used in heavy machinery which require a very very long service life. Steel cages are next, and are used in all kinds of industrial applications. Polyamide are the last. They're cheaper than the other two, quieter, and on paper offer similar performance to steel cages within their intended operating parameters, at least when they're new. Over time, the plastic degrades, and they become more brittle, more prone to failure. They also self-destruct quickly when their limits are exceeded. Their use is often banned in industrial equipment. Look back at the first post in this thread, where A H151F was starved of oil. The other needle roller bearings were fine. They got hot and exceeded their rated temperature, but they didn't self destruct. The plastic bearing however looked like this:

I set out to look for an alternative. Toyota used steel bearings for the other gears, so it didn't make sense for it to be noise related, I doubt you'd ve able to hear the difference for a single gear. The fact they used a plastic bearing in this one case I surmised was for one of two reasons - they wanted to go plastic for all of them if they could, but this was the only size where that was an option, or they wanted to go steel for all the needle bearings, but for this size only plastic was available. Knowing Toyota engineers I figured it was probably the second, but that was in 1990. Maybe there were other options today. After identifying what the actual manufacturer part numbers were for these bearings, a quick check in the Koyo catalog revealed the following:

The one highlighted in yellow is the one we get from Toyota with the plastic cage, part number 90364-58003, which is actually Koyo 58RFN6537A. The one in green is another bearing in the Koyo catalog, part number RS586537A-2. It has identical dimensions and speed rating. The only difference is that it has a metal cage, and a higher load rating as a result. Sounds exactly like what I want! So, it was just a matter of finding a source to buy it... which proved basically impossible. After striking out online, I went to a local bearing specialist shop. He told me they mostly do industrial, and only a few people can actually order directly from these guys due to distribution network deals. He recommended I go to an auto parts specialist, so I headed into Don Kyatts, AKA Terrain Tamer.

I went in with the Koyo catalog and bearing part numbers in hand. He hadn't heard of this bearing at all, but got on the phone with their supplier, and started a bit of a chase for me to figure out how to get this bearing. He asked me to leave it with him, but a few hours later I got a call back. So they got off the phone with Koyo, and apparently, even though this bearing appears in their catalog, it's an "OE" special for Toyota, and Toyota only. They won't sell it to anyone else. I knew how it'd go, but that afternoon I decided to pop into the local Toyota parts department and see if they could help me out. If this bearing is a special for Toyota, there must be a Toyota part number for it, right? Unfortunately as expected, they couldn't do anything for me without a Toyota part number.

I needed a different approach, but I'd worked one out. While I was at Don Kyatts, apart from checking out this very pretty cruiser in their lobby:

I also had the opportunity to poke around their H150/H151 rebuild kit, which one of the guys there was nice enough to crack open for me to have a peek while we were trying to sort out the bearing mystery:

From this I was able to get the remaining manufacturer bearing part numbers I was missing. What I noticed was a pattern in the Toyota part numbers. Sometimes information is encoded into them, and the same is true here. Let's look at one for reference:

The first five digits 90364 are common between them all. Clearly that code represents a general "needle roller bearing" or similar type. The next two digits however are the OD of the bearing. If you check the table, you'll see it's true for all of them. The last three digits appear to be a unique bearing number starting at 1. So 90364-38017 for example says it's a needle roller bearing with a 38mm outer diameter and its bearing number 17 Toyota allocated with that type. We don't know the ID, we don't know the depth, we don't know whether it's a single or double row, whether it has an outer or inner sleeve, but we do know that if Toyota have any other needle roller bearings with a 38mm outer diameter, they should be within that narrow range of part numbers.

We're looking for an alternative to 90364-58003. So, some hunting through the parts catalog and we find this one, 90364-58005:

Right style, visually the depth looks good too! What's the history of this part? It was fitted to Toyota Coaster and Dyna vehicles from about 1993 onwards. It replaced the earlier 90364-58001 part, which was actually a brass needle roller bearing like this one, and is genuinely no longer manufactured by Koyo:

That matches our time frame, wasn't there in 1990 or Toyota would have used it. They didn't want to use the more expensive brass one in the 80 series though, so they settled for the polymer one. When it came to the Dyna and Coaster though, Toyota engineers said no to putting a plastic bearing in a literal truck and bus, so they worked with Koyo and got an OE special custom bearing made up they could replace the brass bearing with. This new bearing part was never used in the H150/H151 though, it stayed with the original plastic bearing to this day.

With this new working theory, I needed to confirm fitment, so back to Don Kyatts and they got the 90364-58005 for me sent up from Melbourne, which they also stock. Arrived today:

The steel version actually has one extra roller due to very slightly different spacing between the rollers in the housing, which doesn't change the fitment but technically makes it a bit stronger. I didn't take pics, but I did physically fit the metal bearing to the output shaft and 2nd gear for a test fit. Perfect, direct replacement, no issues.

So there you have it, there's now a "2nd gear bearing upgrade" available for the H150/H151. Im interested in what other guys like @SNLC who have had their hands into these boxes think about thus upgrade. I'll be doing it in mine.

Oh, and I did basically confirm Toyota wanted to go steel for this bearing originally, because some of the other bearing sizes had polymer versions available in the catalog already, but Toyota added in new bearing numbers for the 80 series which had steel, so I think it's fair to say that's the direction they would have gone for the 2nd gear if Koyo offered the part at the time.

 

[DivByZero]

Oh, I forgot to mention too, you'll discover that for 90364-50001 and 90364-44003, the 1st and reverse gear needle roller bearings, they come up as "out of production" at Toyota under those part numbers. Don't worry, they're not, Koyo very much still make them, Toyota just don't stock them under those numbers anymore. I haven't confirmed myself, but visually, 90364-50003 seems like the identical part under another number (very frequent occurrence), which was used in the 100 series and the Dyna. I couldn't see a drop-in replacement for 90364-44003 in the Toyota catalog (90364-44004 is too deep, 90364-44001 is plastic), but the Koyo part of RP455236A is still manufactured and available. I got mine through Don Kyatts.

 

[ArmyFJ]

Awesome info. Incredible research you are doing on this.

 

[OGBeno]

One very important thing of note - I think I've found a way to accurately identify the production date of these gearboxes from the outside. There is a code stamped on the front bearing retainer:
View attachment 3408849

You can see the code stamped on the bottom of the bearing retainer. On my pre-92 box, it reads 142. On the reported 97 model box, it's 787. That suggests to me the first number is probably year of manufacture. Hey @OGBeno, do you know of any three code date format Toyota stamps on parts? It'd be handy to be able to confirm week, or at least month of manufacture by looking at the outside of these boxes alone.

7= last digit of year: 1987/1997/2007 etc.
8= Month: August
7= Manufacturing day of production: This is different than calendar day. Manufacturing at Toyota and suppliers is generally a Monday-Friday deal. In this instance, it would be August 11, 1997.

Different suppliers use different versions of this code including adding letters (I and O will never be used).

To confirm date of manufacture theory, always cross reference with vehicle build date as well as other assemblies (transfer case, engine, transmission case itself, etc)…. They will all generally be within 5-8 manufacturing days of each other. Inventory is very rarely carried by anyone supplying Toyota…. JIT always.

 

[mudgudgeon]

Awesome info. Incredible research you are doing on this.

@DivByZero your extensive detailed notes deserves its own thread

 

[dudwire]

I've just started the teardown of a H150F from a VDJ79, the previous owner was upgrading to a H152. It has done 250,000kms and at first glance without further inspection it all looks pretty good - with the exception of second gear.

I plan on rebuilding this box to replace the one in my HDJ79 which is starting to get a bit noisy.

Marks on second gear (right side gears).

At first I thought it was wear on the teeth but looking closer it doesn't seem right. There are no markings on the counter shaft gear corresponding with the output shaft gear marks. Also the marks are outside of the contact area you can see on the output shaft gear. I'm not sure what to think of it...

This is also my first transmission rebuild so I also have a couple questions if anyone could help

Mainly to do with the snap rings used. The FSM recommends you replace each snap ring with a certain thickness - are people actually replacing the snap rings for new ones? If so how did you go about the thickness of each snap ring?
I could order each and every thickness of snap ring throughout the transmission but would rather not be left with $100 of unused snap rings.

Thanks!

 

[77mustard40]

I don’t have a manual box in my 80, but this thread is FAQ material. Great work by all the contributors!

 

[ArmyFJ]

I've just started the teardown of a H150F from a VDJ79, the previous owner was upgrading to a H152. It has done 250,000kms and at first glance without further inspection it all looks pretty good - with the exception of second gear.

I plan on rebuilding this box to replace the one in my HDJ79 which is starting to get a bit noisy.

View attachment 3555575
Marks on second gear (right side gears).
View attachment 3555576
At first I thought it was wear on the teeth but looking closer it doesn't seem right. There are no markings on the counter shaft gear corresponding with the output shaft gear marks. Also the marks are outside of the contact area you can see on the output shaft gear. I'm not sure what to think of it...

This is also my first transmission rebuild so I also have a couple questions if anyone could help

Mainly to do with the snap rings used. The FSM recommends you replace each snap ring with a certain thickness - are people actually replacing the snap rings for new ones? If so how did you go about the thickness of each snap ring?
I could order each and every thickness of snap ring throughout the transmission but would rather not be left with $100 of unused snap rings.

Thanks!

I replaced some of them. I based replacement on the fit and shape of the ring after pulling it off. If you replace a gear, I’d recommend checking & buying rings as the fit against the shaft may change.

A micrometer and feeler gauge will help here.
After I measured, I bought the size I measured and +1 and -1 size just in case I measured a little off. The tolerance on these is very tight.

And one more thing…cage or have a helper cage the ring when you pop them off. They like to fly away never to be seen again. Ask me how I know.