Hydraulic oil into Cruiser gearbox?

You had best speak to an oil specialist as while the hydraulic oil works ok for the syncro's it may be no good for the gear teeth which take the load.
I bought a 2wd hilux a while back, low k's but gearbox seemed noisy, dropped the oil and it had ATF in it, proper spec is 75/85 gearbox oil.
Asked an oil specialist (most big oil co's have them) and he explained that yes while it was "ok" especially for shifting it wasn't so good for gear wear, especially the actual load on the gear teeth. He said it was quite common for mechanics to fill manual boxes with ATF especially in small workshops as they usually didn't have the correct oil grade so the "she'll be right" attitude prevailed. Most people would be happy with the improved shifting and wouldn't question what oil was in the gearbox expecting the mechanic to fill with the correct lubricant.
I've now filled it with the correct oil grade and yes the shifting isn't as good especially when cold but the gearbox is noticeably quieter.

Ditto.

How many kms have you done since?

And give us an update after 100,000km or if it blows earlier.

Thanks for that guys...

As my syncro's are in a bad way (before this hydraulic oil & VMX (?) & Nulons treatment), it would be nice to have the best of both world's.

It is silly to combine the 2 oils right? What if I kept the AGRI hydraulic oil in there & then added the Nulon gearbox & Diff treatment?

Cheers

Ro

I used the agri fuid 424 (which one did he use)
The reason I used it was it was highly recommended by a gearbox specialist. Agri fluid (at least the one i used) is designed for high load high stress situations and is perfect for the transmission loads its designed for heavy load agricultural equipment transmissions that use internal brakes/clutches and is less affected by heat.
Here are some extracts the last line is the one -:

A high quality, high viscosity index transmission fluid with extreme pressure additives for transmission and hydrostatic fluid refill requirements to suit a wide range of farm and industrial tractors, mobile contractor equipment and some passenger cars. It also has proven performance in a number of 4WD manual transmissions, transfer cases and power steering applications.

• One fluid for transmission and hydraulic systems

• Excellent extreme pressure protection for maximum gear life

• Frictional characteristics for wet brakes and power take-off clutches

• Oxidation stability, foam control and water tolerance

• Protection against rust and corrosion

Mobil Agri Fluid 424 is a high performance, premium quality lubricant intended for use as a multipurpose tractor transmission and hydraulic fluid. It is formulated from high quality mineral oils and an advanced additive system to achieve outstanding improvements in wet brake and power take off (PTO) chatter control as well as enhanced viscosity retention (shear stability) in field service. It has improved extreme pressure properties that provide superior protection against wear under the most severe operating conditions. Resistance to oxidationand thermal degradation is outstanding and ensures protection against sludge and varnish deposits.

Mobil Agri Fluid 424 resists foaming and provides excellent protection against rust and corrosion. Its low temperaturefluidity ensures effective lubrication and hydraulic performance in cold weather conditions. Mobil Agri Fluid 424 is recommended for topping up and refill of transmissions, differentials, final drives,hydraulics and power steering systems, as well as wet brakes, PTOs and hydrostatic drives in farm, contractor and industrial tractors. It also performs well in 4WD manual transmissions.


Agri also have specific engine oils, these are all mobil products

hi rowen
just looking back at thread 77643 which was your thread re above topic

pleased to hear you are happy with the tractor trans /hydraulic oil in the cruiser g/box
dont waste your money or time adding nulon it wont be any better with it been there done that

the tractor transmision housing
is the resivoir for most tractors hydraulic oil supply
as well supplies the oil for all components

eg: wet disc brakes/
wet pto drive clutches /power steering/ all hydraulic controlls and attachments including front end loader and 3plinkage rams and arms and any towed implements hydraulic equipment as well as lubricating the trans gears under heavy loads also hydraulic driven motors eg : super spreader etc
it is a very high qualitity multi purpose oil for above applications

but i would'nt put it in an engine unless it was the only oil availuble in an immergency
cheers

Does anyone know what causes the problem with Cruiser gear boxes? The last time I worked on Toyotas was back in the early 1980s. We had a lot of problems with the synchros in new Hilux 4X4 boxes. The fix was to drill a 1/16 inch hole through the centre of the little groves across the face of the synchro cones. This allowed oil to escape much faster during shifting and made the world of difference.

The oil we were using back then was Castrol. I can't remember what grade but it was in accordance with Toyota's specifications.

use a light gear oil and shift problems will go away. penrite used to make one and caltex do also so that may be another avenue. IMO i dont care what they say i wouldnt use a hydraulic oil in a trans, short term may be OK but in the long term(may be shorter than long)it will create more trans problems than its worth as it is not an extreme pressure style of oil