Transmission oils revisited.

[Cuppa]

I will be changing oil in my motor, gearbox & transfer case in the next day or two. Probably doesn't need doing as I did it 40,000kms ago, but that was 6 years ago, so I'm doing it so we can leave on our travels knowing we have a 'fresh vehicle'. Both diffs have been refilled recently.

Motor -I'll stick with the Penrite 15w50 semi synthetic in the motor.

Gearbox- Like many others cold gearchanges are pretty stiff & notchy until the box has warmed up. Penrite's 'Pro Gear' 75w85 (full synthetic) claims to improve this. Have you used it & if so did it help? Previously I used Nulon 75w90 (semi synthetic )+ Nulon G70 PTFE gearbox additive so I'm a bit sceptical of claims to make gearchanges smoother. However from another current thread folk are saying a GL4 oil is smoother than a GL5 in a TD42 box. The nulon is GL5 whereas the Pentrite is GL4.

Transfer case - Penrite, BP & Castrol all recommend ATF. Previously I also used Nulon 75w90 (semi synthetic), but am tempted to use ATF if for no other reason than it will be easier to pump it into the case. I'd like to know if anyone recommends ATF over a gearbox oil or vice versa & why. Also if I drain the transfer case well is that sufficient, or would I need to use a flushing process to change oil types? I do have sufficient Nulon 75w90 to do the the transfer case but could be convinced to get some ATF if it is better somehow.

These oils are going to be used towing in hot weather.

All recommendations (or otherwise) welcome.

[nissannewby]

GL4 always for the gearbox cuppa and if your happy to pay the full synthetic is even better.

As for the transfer case well thats up to you. I have always used the same oil for gearbox, transfer and front diff to try and limit the amount of different oils I require. Never had a problem with that arrangement and its always warm up here.

[Cuppa]

Thanks Matt, your recommendation is good enough for me. I'll get the Penrite Pro Gear for the gearbox & warm up the Nulon stuff I already have for the transfer case.

[GQtdauto]

Stopped using semi synthetic for the motor now , my mechanic always used it himself and in any diesel motor but discovered after about 5000 Ks he was having to top up all the time , he talked to his oil man and now has gone back to mineral .
Ours were pretty much the same with topping up so have now switched .

[Cuppa]

Well jobs done. I recall last time I changed the gearbox oil laying underneath the car getting covered in oil whilst taking forever to pump it into the gearbox a small squirt at a time using one of those little 'Tom Thumb' 1 litre pump bottles as a particularly unpleasant task, so was keen to make the job easier this time.

To this end I bought a $15 drill powered rotary pump from Bunnings & a couple of metres of clear pvc hose to fit it. Used my cordless drill to drive it. Can't say there was zero mess, but no puddles, just a few drips onto the sheet of cardboard I put down on the floor. I warmed up the Nulon oil for the transfer case in hot water sat next to our wood stove for a few hours - this made a fair difference to the viscosity. The Penrite Pro gearbox oil didn't need it as it was thinner than I'd expected. The little pump needed priming (that's where the drips came from) but boy did it do a great job! Sure beats hand pumping - the almost 3 litres went into the gearbox in under a minute. Brilliant

Took the car out for a test spin to ensure I had no leaks. I swear the car felt smoother generally & the gear lever required slightly less pressure. Will be interesting to see whether the Pro Gear oil has made any difference to gearchanges from cold - at this stage I'm a bit optimistic that it will have done.

[garett]

i had gl-5 in the gearbox. i dropped it for a gl-4 made a big difference when cold. i went penrite gl-5 to nulon gl-4. having a hoist makes oil changing easy.... :P

[Cuppa]

Yesterday morning there was a hard frost again, a good test to see if the cold start gear change had iimproved with the new oil.

Pleased to report that my optimism was well founded. From completely cold the gear selection was much improved, close to what I have previously been accustomed to with a well warmed up box.

All that time with GL5 oil ...... grrrr.