H55F rebuild? (1 Viewer)

[Gimme a 60]

Hi Mudders!

I have a H55F with 320,000 KM on it. It doesn’t appear to have any active leaks, and the output shaft and drive shaft flanges don’t have any play in the bearings. However I have never felt it shift before or driven it. I was talking to another cruiser head today, and he said that these transmissions normally wear out around 300,000km….. he got me worrying. So my question is, how can I check to make sure my transmission is in tiptop and how long do these transmissions normally last?

Thanks.

 

[lacalvette]

Well, these h55f were fit behind many engine. The 3B was certainly not the hardest on the gear box….12HT on the other hand…
Output shaft spline stays straits…
Unless it ran out of oil, at 300k km it should still be good.

Remove the shifter cover, carefully
check for wear on all bearing (that you can see) and gear (including synchro). Check that bearing turn smoothly.
There is no preload to check in the gearbox as the T-case take care of the thrust.

Clean as much as you can the case and carefully check for metal particule on rag.

I would disassembly the T-case to change the lip seal between the gear box and T-case and inspect the input gear lip seal contact surface. The fj62 new style seal is an upgrade. They seem to be prone for failure and oil from T-case migrate into the gearbox.
A general inspection of all components,
Idle shaft bearing contact surface seem to wear.
check output shaft bearing preload.

Grab the seal with your finger and see if they are still soft and flexible. If they are hard and brittle, that’s not a good sign (overheat history?)

You could also change the gear box input shaft seal and both output shaft seal on the T-case as a preventive maintenance

Edit: if you remove the shifter cover, make sure everything shift after you put it back. (The reverse gear may have shift and not be aligned with the fork)

 

[Gimme a 60]

Okay, well funny enough. My FJ62 is the one that had bad seals… I had to rebuild the transfer case after the automatic trans fluid drained into the transfer case. I was able to take a look inside of the trans where the shifter went, and it looked very clean inside and no visible damage to the gears. I was even able to take a look at one of the synchros, it looked clean as well. I’m not experienced at all with transmissions. So I’m going to leave it, I just hope it shifts well when I install it…. I read that from factory these aren’t smooth shifting.

 

[lacalvette]

You could use your FJ62 T-case behind the H55F. You would have the latest version, 38mm idle shaft and you know that it runs good too.

 

[Gimme a 60]

You could use your FJ62 T-case behind the H55F. You would have the latest version, 38mm idle shaft and you know that it runs good too.

Yea, it’s vacuum shift, not a huge fan of it. But I might hang onto it, because the h55f is actually going into the FJ62.

 

[lacalvette]

You can use parts from your 84 and retrofit mechanical linkage on your FJ62 T-case
You have everything needed

 

[OSS]

Only accurate way to determine the health of rhe transmission is to drive it. —- unless you want to completely disassemble it and measure clearances.

Removing a transmission thats mounted on the vehicle isn’t too hard if you’ve got a good transmission jack. My vote is just assume its fine and install it. If it turns out to be junk after driving with it, drop it & replace with a new one.

 

[GM60]

There are two things that I always do with an h55 and splitcase of unknknown condition prior to installation.
First, always always always replace the gearbox input shaft seal.
Second, check for wear at the splines of the transfer case input gear and the gearbox output shaft.

This can be done easily when the trans is out and with no need to split the transfer case.

 

[Freewheel]

When warm, the H55F shifts quite nicely for a heavy truck transmission. To keep it shifting year round like it's warm, use Synthetic Gear oil. Redline MT-90 made mine feel brand new. Easiest improvement you can make to it!

 

[cps432]

I’m going to hijack this thread a little to ask a question since we’re talking about 5 speeds.

I installed mine about two years ago and it runs and shifts like a dream. I use redline synthetic oil. It has fewer than 10,000 miles on it. Drove across the country twice with very heavy loads and the transmission performed flawlessly.

Recently my engine took a dump and I’ve pulled everything out for a rebuild. While moving my transmission on the jack I noticed play in the input shaft. If feels like a lot. I have no leaks. No wear on the splines. Pilot bearing is in tip top shape. How much play is normal for the input shaft? I’m really hoping nothing is happening internally to my fairly new transmission…

 

[OSS]

I noticed play in the input shaft.

That’s normal.

 

[Godwin]

I’m going to hijack this thread a little to ask a question since we’re talking about 5 speeds.

I installed mine about two years ago and it runs and shifts like a dream. I use redline synthetic oil. It has fewer than 10,000 miles on it. Drove across the country twice with very heavy loads and the transmission performed flawlessly.

Recently my engine took a dump and I’ve pulled everything out for a rebuild. While moving my transmission on the jack I noticed play in the input shaft. If feels like a lot. I have no leaks. No wear on the splines. Pilot bearing is in tip top shape. How much play is normal for the input shaft? I’m really hoping nothing is happening internally to my fairly new transmission…

Yes, normal as OSS said, pilot bearing supports end of input shaft when transmission is installed.

 

[cps432]

That’s normal.

Yes, normal as OSS said, pilot bearing supports end of input shaft when transmission is installed.

Thanks guys! I was a little worried last night when I measured more than 50 thousandths of play. Godwin, I was about to ask if you could measure yours if you have your H55f out of the truck still, but you’ve alleviated my worries.

 

[Gimme a 60]

Thanks guys! I was a little worried last night when I measured more than 50 thousandths of play. Godwin, I was about to ask if you could measure yours if you have your H55f out of the truck still, but you’ve alleviated my worries.

Phew!

 

[sodafeld1]

I have replaced the bearing shim on the transfer output to the rear drive shaft with transmission and transfer on the troopy.

It got slopped out from heavy towing on bad roads. The drive shaft bolts got loose and caused a steering vibe over 80km/h.

The shims come in quite a range of sizes.
Obviously mr. toyota expected these to be serviced due to the ease of access to the rear bearing housing of the transfer, once the rear drive shaft is removed.
I kinda cheated with the torque value freeplay by using the lowest setting on a bicycle torque wrench. A little resistance but no slop.

One of the easier ones to have a look at on a h55 transfer whilst you are at it.

 

[Eurasiaoverland]

320k kms might be end of life if it has been abused, or happy mid-life if it has been looked after. I personally would not chuck it straight in while you have it out.

Unless you need to work on the transfer case output shaft (press on new bearings or gears), the transfer case can be easily stripped down with hand tools (you need a basic puller to get the PTO gear/transfer input gear off). That will let you look at the splines on the transmission output shaft, which is one common wear area. You can also check how the transfer high and low range gears run on the shaft.

Taking the top off the H55F, you can inspect the shift teeth on the gears and input shaft which may also wear with high miles.

Those simple steps will reveal a lot about the condition of the gearbox and are very easy compared to stripping down the entire H55F.

EO

 

[Gimme a 60]

320k kms might be end of life if it has been abused, or happy mid-life if it has been looked after. I personally would not chuck it straight in while you have it out.

Unless you need to work on the transfer case output shaft (press on new bearings or gears), the transfer case can be easily stripped down with hand tools (you need a basic puller to get the PTO gear/transfer input gear off). That will let you look at the splines on the transmission output shaft, which is one common wear area. You can also check how the transfer high and low range gears run on the shaft.

Taking the top off the H55F, you can inspect the shift teeth on the gears and input shaft which may also wear with high miles.

Those simple steps will reveal a lot about the condition of the gearbox and are very easy compared to stripping down the entire H55F.

EO

I can’t afford to put any money into it.


The PO daily drove it, and said it shifted the way you would think it would shift……. Who knows.


Is there a gasket that I will have to replace if I take off the top of the H55F? I like the idea of inspecting.

What do I look for? Overall health of the synchros? From what I have seen through the shifter hole, it looks clean on the inside.

 

[Eurasiaoverland]

I can’t afford to put any money into it.


The PO daily drove it, and said it shifted the way you would think it would shift……. Who knows.


Is there a gasket that I will have to replace if I take off the top of the H55F? I like the idea of inspecting.

What do I look for? Overall health of the synchros? From what I have seen through the shifter hole, it looks clean on the inside.

In a pinch you could just silicone the top cover but a paper gasket is a few dollars. You could even make one as it's not a complex shape.
You won't be able to see anything informative about the synchros (unless they are seized on the gears), but you can see if the shift teeth (the pointed dog teeth where the shifter sleeve engages the gear) are worn (rounded or chipped). You can also look at the gear teeth for wear/chipping. Have a look under the input shaft at the countershaft teeth too. If you want to really measure wear in the box you can slip a feeler gauge behind 3rd, 2nd and 1st gears and compare to specs.

 

[Gimme a 60]

So, I started to tear down the the transfer case, and noticed that it has clearly been fully rebuilt.

It noticeably has new O-rings, idler shaft, roller bearings, races, and possibly gears. It looked very very good.


Now, I took the transmission top off, I don’t know what to look for….. think there is a synchro issue?

 

[Eurasiaoverland]

Looks pretty much brand new to me but as I said, looking really tells you nothing about synchroniser rings - they wear where the grab the taper on their respective gear.

Given that everything on this transmission looks good, I would say bolt it back up and enjoy it.