Blown gearbox 79series

[mickbeny]

Hi all...The gearbox blew in my 79series 2000 model,it is a 1hz with aftermarket turbo fitted..Ive heared that the newer factory turbo diesels have a stronger gearbox?.Is it possible to upgrade the internals of my gearbox to make it as strong as the newer gearboxes or stronger???Or is there aftermarket parts i can fitt into my gearbox to make it stronger??
We dont even know what the problem with the gearbox is as of yet,but the vehicle will be off to the mechanics tomorrow morning and its going to get fix stronger if possible.All ideas welcome.

[beanz2]

I've only heard of the output shafts splines wearing out on these R151 gearboxes, but please report back as to the actual damage it sustained. I believe in 2002 Toyota upgraded their output shafts.

Indeed the factory turbo diesel uses a larger and stronger gearbox, the H151 and its own transfer, but the gearbox internal parts aren't compatible with the R151 despite the name similarity. You can fit the entire gearbox and transfer from the turbo diesel, but I believe you may also need to change your flywheel to a turbo diesel unit or at least redrill it to accept the larger clutch. Someone else more knowledgeable may add later in this thread.

If you can take pictures of the gearbox damage and e-mail them to me, I'd be happy to post the pictures here for all of us to see. dtay@comcast.net

Dave

[dow50r]

Turbo plus weight usually starts the clock ticking on these boxes, found in all 1hz 100's, 78/79.s
You can get an 80 series diesel gearbox and transfer and fit it up fairly easily. The left over bits will be well picked off your hands by the hilux guys with v8's.
The only down side is the first gear low range is higher (4.5x2.45x4.3?)
If you find a h150 gearbox from a 1995 or later std van, you will get a part time case, and the best shifting box out of the 80's.
Andrew

[mickbeny]

Hi all...The problem is the gears that opperate 1,2,3 gears stripped.the problem was due to no or little oil due to my neglect more so,the tranfer was full.But the common weak spot for these boxes was on its way out also,it is a 2 piece shaft and was well worn on the slipper where they join together.Toyota upgraded this part to a single shaft,this upgrade will go into my box.These boxes are so tiny compered to the old 75series box.

I have a pic and will get it up soon.

[dow50r]

They were used in the turbo supras...prados, and now in the 1hz powered heavy duty cruisers...better ratios but not so good when you have to visit Mr Toyota with a mortgage already signed.....
Andrew

[HIL01X]

A gearbox reconditioner bloke told me that these gearboxes are going to be their next big money maker. He said you have to keep them overfull with oil to keep the input shaft from overheating and stripping the teeth off. It can happen in as little as 8000km from new.

[mickbeny]

Hi all...I got 160,000 klm out of mine,60,000 klm with the turbo,and i even towed a camping trailer to capeyork last year.Ive also got ARB difflocks front and rear.Although they are weak and not suited to the cruisers,in my case i say they are not piss weak.Maybee i was just luck to get them klm.

Does the newer deisels have the same box as the new TD 78/9.???

[beanz2]

Does the newer deisels have the same box as the new TD 78/9.???

No, the n.a. diesels have the same box as the turbo diesel Bundera. The TD 78/79 have a much larger gearbox.

Dave

[dow50r]

Gday
The 78/79 t/d uses a h150....but it has slightly different ratios to the 80 series one.....taller 5th and lower first from memory.
Andrew