H55 conversion (1 Viewer)

[PabloCruise]

It does kind of suck that Toyota a) never gave the US a 5 spd, and b) designed a 5 spd that relies on a $3 plastic oiler cup to prevent failure, c) prices this technology ~$2000.

 

[lumpy70]

It's possible that someone (who shall remain nameless) up here might be asked to build the aforementioned adapters...If I hear anything I'll post it.

 

[SteveH]

TJ - there are a number of 'overdrive' transmissions where the overdrive gear is an afterthought, and suffer reliability issues. Agreed that Toyota should have offered a 5 speed in the US, especially on the FJ62, which is so hampered by the energy-sucking automatic.

 

[PabloCruise]

TJ - there are a number of 'overdrive' transmissions where the overdrive gear is an afterthought, and suffer reliability issues. Agreed that Toyota should have offered a 5 speed in the US, especially on the FJ62, which is so hampered by the energy-sucking automatic.

Just a tough price point for the design is my thought...

 

[niffa]

Here in straya i have always been told u shouldnt tow heavy loads in 5th gear. That goes for all vehicles with 5 speeds. Top gear is for cruising not lugging. shock loading on the gear is no good. My h55f has 550,000klm on it and is going strong because i dont flog it. Change gear oil and shes happy.

 

[arnott1t]

So I was one the guys involved in helping the frenchies with their failed h55 over Christmas. This counter ahaft failed after 400k total km and 90k after a rebuild. It was missing he oiler cup. We stole parts from a behemoth60 600k km trans for a counter shaft and some other bits. Those bits looked to be in fantastic shape for their mileage.

The break was certainly a fatigue failure propagating from the lock pin near 5th


Tonight I pulled another h55. This one was an odd failure. In a bj74 daily driven and seeming well maintained. Oil change to full syn lube for the winter in November. Not making metal and the magnets only had typical wear particles. Last Saturday this bj74 drive out to the trail head and notices that the trans popped out of 5th once. He put in back in and all was well. We then spent 2 hours on the trails. Easy creepy crawly slippery trails. Got back to trail head and say our good buys. He's on way home and each gear is making a noise except 4th. 5th can't even be held in. Limps home in 4th. I retrieve the truck on a trailer and here we are.

4th

5th

Front intermediate shaft bearing

Front intermediate shaft.


All this to say the h55 can be a great transmission. I just wouldn't give it the bullet proof tag. In Fact it may even be considered temperamental now to me.

That being said I like the way it shifts and like it when it's working. I just wish we had options. Even expensive ones. Just options.

 

[enfield]

I would be very interested in seeing someone do some more legwork on the ZF/2F adapter. ZF 5spds are bulletproof and extremely common in these parts.

 

[Behemoth60]

I would be very interested in seeing someone do some more legwork on the ZF/2F adapter. ZF 5spds are bulletproof and extremely common in these parts.

I am the culprit who goaded Lumpy70 into his heretical post re: the failure rate of the vaunted H55f. I am also in possession of numerous H55f’s, every one of them broken beyond repair for a variety of reasons. Most of them have been countershaft failures, possibly induced by front bearing failures. I did have a low oil induced front input bearing failure too, precipitated by the notorious ‘Pumping Oil’ failure mode that tends to drain oil out of your H55F and overfill your split case.

If you run an H55f within the performance enveloped it was designed for circa 1980 then you you have a great transmission for 90 kmph speed limits, with 29” tires, and behind 90-120hp engines. But… 35 years later, we run them at 130 kmph, behind V8’s or jacked up turbo diesels, with 35-40” tires. Clearly, this is why I have so many dead H55f’s in my possession.

While we Canadians did get a few thousand factory installed H55f's behind B and H motors in the 80's , new replacement B series input shaft have become unobtanium from Toyota. While you can still buy brand new H55f units for your H/F series motors, you are totally out of luck if you don’t have a donor input shaft for your B engine. And Input shafts are often destroyed when counter shafts fail… so, they are getting kind of scarce.

Which leads me to some of that aforementioned leg work…. My recommended replacement is, as already mentioned, the ZF5 S-42, specifically the early 90's Ford truck units from behind a gas engine, it had the following gear ratios.

5.72 2.94 1.61 1.0 0.76 -5.24
10 spline, 1-1/16" input shaft.
11" clutch.
31 spline output shaft.
Integrated bell housing with All aluminum case.

Here’s my KickStarter Idea:
Build a custom Adapter plate to go between B engines and gasser-version ZF S5-42 transmissions which use a factory Toyota starter and tach sensor. Use the F engine clutch (10 spline, 1-1/16 shaft, 275mm clutch). Use Factory Ford Clutch master/slave.

As for transfer cases, you have your choice of the Ford NP203, NP205, or NP271. Aftermarket Atlas Tcase are also available, which would the winning option if that’s in your budget. Another custom adapter to the Land Rover transfer case is also an interesting idea but more custom adapters with shaft adapters… all gear, offset rear output, AWD case with a fantastic reputation.

There’s a bunch of R&D to confirm that it’s even possible considering flywheels, starter locations, tack sensors, input shaft lengths, and so on, and so on…. But, no one invested in my kickstarter, so there you have it. I continue to toy with this idea for my own project.

 

[JMJA]

Question on oiler cup. I'm looking at the 5 speed repair manual #223-08. It doesn't show the oiler cup in the diagram. Is it called something else or is this a part that is added to the H55F after a rebuild?

 

[OGBeno]

Question on oiler cup. I'm looking at the 5 speed repair manual #223-08. It doesn't show the oiler cup in the diagram. Is it called something else or is this a part that is added to the H55F after a rebuild?

It's not technically a part of the transmission assembly. It is a parts of the transfer case assembly.

 

[elripster]

Lack of oil will do it to anything. I had the issue where the t-case seal failed and the t-case pumped its oil into the transmission ruining my t-case. The hoses between the two is the same fix there. I don't see this as an H55F issue unless, for example, new H55F seals and/or oil cup are failing at a low mileage (what is the typical mileage of the failures?). In fact, I would rather replace just 5th gear than have to rebuild/replace the whole t-case for what it's worth.

In Canada your H55's are probably in the condition my 4 speed was when I pulled it making grindy bearing noises and all. In my case I just see it as a 30 year old car part wearing out. Unlike metal, seals / plastic parts wear just from age.

I do think it would be helpful to get some ballpark mileage to failures if that is at all possible. If these are 200k mile failures it's one thing but if they are 50k mile failures it's another.

Frank

 

[ModisetteJ]

I am the culprit who goaded Lumpy70 into his heretical post re: the failure rate of the vaunted H55f. I am also in possession of numerous H55f’s, every one of them broken beyond repair for a variety of reasons. Most of them have been countershaft failures, possibly induced by front bearing failures. I did have a low oil induced front input bearing failure too, precipitated by the notorious ‘Pumping Oil’ failure mode that tends to drain oil out of your H55F and overfill your split case.

If you run an H55f within the performance enveloped it was designed for circa 1980 then you you have a great transmission for 90 kmph speed limits, with 29” tires, and behind 90-120hp engines. But… 35 years later, we run them at 130 kmph, behind V8’s or jacked up turbo diesels, with 35-40” tires. Clearly, this is why I have so many dead H55f’s in my possession.

While we Canadians did get a few thousand factory installed H55f's behind B and H motors in the 80's , new replacement B series input shaft have become unobtanium from Toyota. While you can still buy brand new H55f units for your H/F series motors, you are totally out of luck if you don’t have a donor input shaft for your B engine. And Input shafts are often destroyed when counter shafts fail… so, they are getting kind of scarce.

Which leads me to some of that aforementioned leg work…. My recommended replacement is, as already mentioned, the ZF5 S-42, specifically the early 90's Ford truck units from behind a gas engine, it had the following gear ratios.

5.72 2.94 1.61 1.0 0.76 -5.24
10 spline, 1-1/16" input shaft.
11" clutch.
31 spline output shaft.
Integrated bell housing with All aluminum case.

Here’s my KickStarter Idea:
Build a custom Adapter plate to go between B engines and gasser-version ZF S5-42 transmissions which use a factory Toyota starter and tach sensor. Use the F engine clutch (10 spline, 1-1/16 shaft, 275mm clutch). Use Factory Ford Clutch master/slave.

As for transfer cases, you have your choice of the Ford NP203, NP205, or NP271. Aftermarket Atlas Tcase are also available, which would the winning option if that’s in your budget. Another custom adapter to the Land Rover transfer case is also an interesting idea but more custom adapters with shaft adapters… all gear, offset rear output, AWD case with a fantastic reputation.

There’s a bunch of R&D to confirm that it’s even possible considering flywheels, starter locations, tack sensors, input shaft lengths, and so on, and so on…. But, no one invested in my kickstarter, so there you have it. I continue to toy with this idea for my own project.

Did you ever give this a shot? Engine needs rebuilding in my 60 now, so I think it's time to consider the tranny as well while I have it all pulled.

 

[Behemoth60]

Did you ever give this a shot? Engine needs rebuilding in my 60 now, so I think it's time to consider the tranny as well while I have it all pulled.

No, this concept never made it past the 'Good Idea' phase.

 

[cruiserpilot]

Now I'm interested as I have a BJ74 I just bought with an apparently damaged 5 speed.
This 13B-T powered, stock boost with 308,000 kms. I haven't had time to pop the top to
look at it yet. It is the first 5 speed failure I'd heard of but I didn't get any info as to what
was happening or whether anything was amiss until it gave up at highway speeds. I do
know the truck had been regularly serviced and is in really nice condition otherwise.

I am curious as to why the NV4500 trans never came up in conversion conversation. I understand AA has an adapter plate
for the 2F to the NV4500 does it not, or just to the transfer case? I have a '74 FJ40 in my backyard with a 350/NV4500
stock t-case.

Has anyone documented with nice clear pictures the hose placement between the trans/t-case on the H55? And I'm not sure what this oil cup is? Explain please

 

[Michael Hanson]

Hi, How available are parts for the 5 speed if they need service ? Mike

 

[Output Shaft]

Part$ are available for the H55F.

But if a lot of parts need replacing, they quickly add up to close to the price of a whole new unit.