LT95 Oil

[bobakers]

Hi all

Can anyone give a reason (other then price) that I shouldn't use royal purple synchromax in my perentie 6x6?

thanks
Bob

[Bearman]

Any particular reason why you would want to use it?
The LT95 box and transfer case is happy to use 15W40 diesel engine oil the same as the engine, which makes it easy at service time. Although if you have synchro problems the synthetic oils work a bit better than the 15W40. Light viscosity oils are recommended because of the oil pump in the gearbox. 15W40 is what I have used in my boxes for over 25years with nil problems.

[Mick_Marsh]

The recommended oil is a SAE30 mineral oil. (OMD-115 is an SAE30 oil)
Penrite HPR30 20W-60 can be used where SAE30 is specified.

Years ago I used something different and it destroyed the transfer case (an expensive lesson). I don't know what the specs of the oil you suggest but I have been told by many people (including mechanics who rebuild these gearboxes) that synthetic oils should not be used in LT95 gearboxes. Something to do with the synchros.

Do a search on this site for LT95 oils. It has been discussed many times.

Whatever you decide, let us know how it went.

[Homestar]

I keep it simple and use whatever I use in the engine I'm the box as well - you only have to carry around one top up oil then. :)

The LT95 is a truck box - pouring expensive oil into it won't make it any better IMO but the spec on the oil you've suggested would suit the LT95 I think, unless there's something in it that will harm the bronze bits, but the viscosity is correct.

[bobakers]

Hi all

appreciate the KISS principle and sticking with 10W40.

Having said that have used RP syncromax in D3 & D4 transfer cases with no issues and don't believe that there would be any incompatibility with materials in the LT95.

Just thinking that this would provide better protection of internals, smoother shifting and able to withstand greater loads/temps. price wise I've been paying $25/ltr

Reading through the many posts (& working in and with the DoD) the standard philosophy of OMD115 in everything is not necessarily based on best engineering practices.


Thanks

Bob

[dranoweb]

I'm using castrol 15w40 synthetic in everything - though I'm noticing shifing issues when sub 10 deg C temps.

Though oil may be a little low, I suspect leaky output shaft seal again.

[normie]

The reason we use 15w40 engine oil is the gearbox has an oil pump and if you put diff and gearbox 90w its too thick for the pump and will destroy pump first then the gearbox. Whether the oil is synthetic dose not matter

[deansyorath]

Having researched....and having a mechanical background.
I would use 15/40 or ATF.
I can remember MB using ATF in gearboxes for their light truck range, we used to drain it and put in ELF synthetic.
But that's just my opinion.
W

[PhilipA]

I always used 15W-50 in the LT95 in my RRC 77 which I owned for 13 years.
I once tried 20-60 to try and make it quieter and I couldn't change gear when it was hot.

I had another RRC in Saudi which someone had put EP90 into and the oil pump shaft was broken and all the thrust washers eaten away.

To me 15-50 engine oil is the go.

Regards Philip A