H55F rebuilt gearbox that whines under load and occasionally jams when parked (1 Viewer)

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I recently purchased a fully rebuilt H55F gearbox and transfer case (by a Toyota 4x4 gearbox specialist) which has now been fitted into my FJ55 with a 2F engine.

First impression was the whine under load in 4th and 5th gear was excessive. To the point where it's almost as loud as the engine. I flagged this with the guy who rebuilt it and he told me that there are new parts meshing with old parts and that it will need a 10k break in period. Sort of understandable but even if it was half as loud after a year of driving then it would still be a noticeable whine.

The gearbox has also completely jammed up when parked on 2 different occasions over the last month. After rocking the car back and forth, side stepping the clutch, jacking up the rear of the car and generally wrestling with it for 30 mins to an hour it finally un-jams.

Again, I've gone back to the guy and he's now shrugging his shoulders as to why it's getting jammed.

Has anyone had similar issues to this with a rebuilt H55F gearbox?
 
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I can't speak to the locking up part, but check the fluid levels in your gear box. The only time I've had excessive whine, the fluid was low. Once topped off, it was vastly more quiet. If it is newly rebuilt, it should be full. If it isn't, check the fluids in your transfer, as that seal is probably bad & fluid is pushing past it. If neither of those is the case, then I'm out of ideas.
 
"Toyota 4x4 gearbox specialist" is often a self-proclaimed title.

How long from the time it was rebuilt to when you installed it? What gear oil did you put in it? Did the shop say where the box originally came from? Did you mate he split case to it, or did the shop?
 
wonder if either the shifter seat is worn/gone or the plastic bit on the end of the shifter stalk.
is it as tho it is in 2 gears at once?
 
Thank
I can't speak to the locking up part, but check the fluid levels in your gear box. The only time I've had excessive whine, the fluid was low. Once topped off, it was vastly more quiet. If it is newly rebuilt, it should be full. If it isn't, check the fluids in your transfer, as that seal is probably bad & fluid is pushing past it. If neither of those is the case, then I'm out of ideas.
Thanks SugarBear, it's going in for a 2nd rebuild now so all will be revealed soon. Out of interest, how do you check if the gearbox/transfer case is properly full?
 
Slide underneath your truck just behind the tranny, and you will see two large threaded plugs. One is on the very bottom, this is the drain plug. The other is on the rear/vertical surface, this is the fill plug. I don't recall but I think it is like a 17-19mm socket. unscrew the fill plug & stick your finger in there. the oil level should be right at the level of the plug (so basically if you can stick your finger in & tough oil right away). If not, it is low. You add oil slowly until it just starts to weep out the hole & then screw the plug back into place. Someone here can confirm, but it is like 90w hypoid gear oil, or so.
Basically the same thing for the transfer case, but the plugs are in different spots (but easy to find). If the whole thing is newly built, and the tranny is low, you will probably find a bad seal between them & way too much fluid in the transfer (pressure differential will push the fluid into the transfer case).
Buy a little screw on the bottle/hosed push pump thing for gear oil. It really stinks, and trying to pour fluid from the bottle is just a guarantee to spill it everywhere & get to smell if forever!
 
Buy a little screw on the bottle/hosed push pump thing for gear oil. It really stinks, and trying to pour fluid from the bottle is just a guarantee to spill it everywhere & get to smell if forever!

Anybody else love the smell of gear oil?
 
Thank

Thanks SugarBear, it's going in for a 2nd rebuild now so all will be revealed soon. Out of interest, how do you check if the gearbox/transfer case is properly full?

Anybody else love the smell of gear oil?

Funny! I wondered if anyone would say they liked it! I like the smell of most car fluids, and also machine shop cutting oils, but for whatever reason, gear oil just go against the grain for me!
 
Slide underneath your truck just behind the tranny, and you will see two large threaded plugs. One is on the very bottom, this is the drain plug. The other is on the rear/vertical surface, this is the fill plug. I don't recall but I think it is like a 17-19mm socket. unscrew the fill plug & stick your finger in there. the oil level should be right at the level of the plug (so basically if you can stick your finger in & tough oil right away). If not, it is low. You add oil slowly until it just starts to weep out the hole & then screw the plug back into place. Someone here can confirm, but it is like 90w hypoid gear oil, or so.
Basically the same thing for the transfer case, but the plugs are in different spots (but easy to find). If the whole thing is newly built, and the tranny is low, you will probably find a bad seal between them & way too much fluid in the transfer (pressure differential will push the fluid into the transfer case).
Buy a little screw on the bottle/hosed push pump thing for gear oil. It really stinks, and trying to pour fluid from the bottle is just a guarantee to spill it everywhere & get to smell if forever!
Have you thought about a change over unit?.....Fitted with warranty.
The workshop that supplied the gearbox are going to honour their warranty on it. They said it'll be rebuilt or replaced.
 
Here is a picture for reference on the fill plug on the back of the transfer case. The idler shaft is in the middle with the flat spot and all the ribs running to it. The oil fill plug is in the eight o'clock area. Believe it's 24MM, I'll check tomorrow.


IMG_2739.JPG
 
Thanks guys, it is indeed a 24mm socket. I checked the levels and a tiny bit of oil weeped out of the filler plug. I stuck my finger into the stench and sure enough it was filled to the top.

Speaking of the stink of gearbox oil, I once had a tour around the Redbull Formula 1 factory where they have a dedicated gearbox workshop. The room was surgically clean but it reeked of gearbox oil. The guys that work in that section spend every working day in there assembling and disassembling F1 gearboxes. I guess they like the smell...
 

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