H151F manual gearbox rebuild

[frank rabbets]

A few more pics coming soon to finish them off.

Should be ready to do the road test by the end of the weekend/Monday. If Ian's box was rebuildable then anyon's will be barring a failure of a major component. The tolerances on the main shaft wear and gearwheel side clearances were slightly beyond the acceptable according to the Toyota workshop manual but I'm convinced the only problem if any will be the syncro's which weren't brilliant on a new box anyway.

Frank

 

[Jon Wildsmith]

ACH]tp://www.mudtoys.com/elcoc/ians gearbox rebuid final 003.JPG[/IMG]
The two big bolt head looking things either side of the top housing are spring loaded pins that you push against to select 1st/2nd or 5th/R. They are different strengths so you want the the right way round. The darker one goes on the left and is for 5th/R. The lighter one on the right is for 1st/2nd.

side shots of the casing. The reverse light switch goes in the hole without a plug in this pic. The plug at about the same level but further along seems to be a left over from an older design. If you put a switch in that hole it will be triggered when you put the box in top (5th) gear. No idea why you'd want to have an indication of top gear though?

tp://www.mudtoys.com/elcoc/ians gearbox rebuid final 007.JPG[/IMG]

Bell housing is back on.

e gear switch installed.

oil seal covered up to make sure nothing can sneak in there while putting it in the truck.

tick hole covered up as well.

Frank did of the interlock set up on the gear selection rods

 

[Gary Stockton]

Maybe you'd want a 5th indicator for towing?? Just a thought - heavy towing should be done in 4th, right!? On a 1:1 ratio?

 

[frank rabbets]

That's right Gary. A lot of the older cars had a light which came on in "overdrive". The standard reversing light switch works really well in this position as I found out when I put it in this hole by mistake. In 5th my reversing lights came on. Lucky I had a reversing camera on the same circuit as I would have been none the wiser.........for a bit.

Frank

 

[ajnabi]

Maybe you'd want a 5th indicator for towing?? Just a thought - heavy towing should be done in 4th, right!? On a 1:1 ratio?

Gary, with 5th being located in the middle of the box it's not a problem with the H151F, on others 5th is located at the back of the box, making them weaker.

Frank/Jon, thank you for taking the time and effort to document this for the rest of us - it's fascinating!

Are you doing requests? Would love a full 1HD-FT rebuild!
...
ok, ok... maybe that might be too much, and unlikely, with the reliability of said engine!

Imtiaz

 

[frank rabbets]

The 5th gearwheel, shaft position and needle rollers were the worst worn of all the gears. By far.


Frank

 

[Chris]

Frank, how feasible (easy) would it be to test a box off the vehicle? I have a very new looking box sitting here and to the best of my knowledge it's fine. Is it relatively easy (relative is a relative term you understand) to 'inspect' it? I stuck a wooden handle in the top housing and went through the gears. Not a real test I know as nothing was spinning and there was no load. But it felt absolutely gorgeous.

Chris

 

[frank rabbets]

Hi Chris

You can go through the gears and make sure they all click firmly into place, and in each gear turn the input shaft several times round to make sure all the gearwheels have no crunchy spots. Also test for for and aft play in the input shaft and also up/down. There should be almost none on either. You won't be able to test the synchros untill you drive it. Also if you take it apart to inspect the synchros they may look OK but may be week. You can test for play in the output shaft. You can tape up the oputput shaft and fill the whole box up with a mixture of parrafin and oil and flush it to see if any bits come out. You can take off the gearlever housing and see some of the internals. Perhaps they changed it under warranty because the customer didn't like 2nd gear synchro. Any history?

Let us know
Frank

 

[Chris]

Thank you Frank. I'll do that. No, no history. It was bought as stock from a closing down dealer. Always assumed as new and being sold as such. I looked at it and found slight witness marks where it had clearly been bolted up, clutch dust etc. I removed the oil drain and a little golden honey ran out. Not a speck of swarf or anything on the plug. Even the stickers look like new. If it has been run, it's never seen rain! If it was a warranty job, I'd have expected it to have been returned to Toyota. Generally the dealer doesn't get paid until the fault has been accepted back at HQ so I understand. IN all it looks mint and too new to have developed a fault. I would not think that it would leave the factory with a fault. They aren't made in Solihull after all. So I bought it and stuck it under a sheet.

Chris

 

[Jon Wildsmith]

maybe they don't bother shipping big parts like gearbox's back to base? I'd take the case off and have a look inside

 

[Chris]

Oh given the value (£6000) I would think that they would.

C

 

[frank rabbets]

Hi Chris
If it came from a main toyota dealer the most likely situation is that it was left over under a warranty claim, and most likely from a fussy customer. So I doubt whether it will have a major fault. I don't think it would be returned for rebuilding especialy if it were over 12 months old and an insurer was involved. On the other hand perhaps a customer just paid for a new one and didn't take his old one away. As Jon said just take the case off and have a look. It will not fly apart. If it looks OK swap it over like I'm doing...............go on.

Frank

 

[Jon Wildsmith]

maybe a bit of 3rd gear dog tooth was found in the oil

 

[karl webster]

I'm not saying I can help this min. But, I could leave a running engine on a chaise and whoever wanted to try there box could drop it on the rolling chaise to test it. Prob as much time as a straight forward swap over in a truck though.

 

[Jon Wildsmith]

have to be able to drive it around Karl so there is load going through the box when the synchros are engaged. It's not all that much work to change a manual box really, easier than an auto, but it would be less work on a bare chassis!

 

[frank rabbets]

We've got spares for that part if they've lost it Jon.

Frank

 

[Dave2000]

Great thread and a credit to the OP, my gearbox has started playing up and I am contemplating a rebuild. I have rebuilt dozens of gearboxes but it is always good to have a reference for when the ageing gray matter falls asleep, I have copied some pics for future ref, many thanks.

A pat on the back,

regards

Dave

 

[Jon Wildsmith]

Frank is the brains of the team, I am just the tea boy (I drink the tea not make it )

 

[Chris]

Sorry Frank. Missed your post in there. It's been my experience that as dealers are generally a franchise, the parts don't belong to them and in order to get their money back from the manufacturer, the parts have to be returned. I had this with a set of wheels once and a who transfer box. The manufacturer has to satisfy themselves about the fault before they pay out. It's not about rebuilding it. They must have piles of things.

I can't really swap the box out as mine is an auto. I just bought this box on a whim as it was there, shiny and I figured worth having for the money and as they get rarer, might come in handy. That was of course until some fools started a gearbox repair service That's my profit gone.

It's a mystery for sure. It should be in really tip top condition inside but for any apparent fault. There certainly can't be much in the way of wear. It'd be nice to do an autopsy on it though. I figured that if I came across a nice 24v manual that had a dickey box, I could beat them down and then stick this in once I got it at rock bottom price. Ooh, would I..

Chris

 

[frank rabbets]

Hi Chris

My original box is 1995 and has done 134,000 miles. It still has the paper stickers..............but is very dirty. Good idea to buy a manual with a crunchy box. You are fussy...........you'll never find one!

Frank