Isuzu MSA Gearbox Oils and Gear shifts

**rick130** · 12th October 2014, 04:30 PM

Originally Posted by isuzurover

I found syntrans even better than vmx80. However I takes 1000 k's or so to fully bed in when you first switch to it.

Originally Posted by bee utey

Probably worth putting a cheap load of engine oil through it for a week or 2 to flush it.

The new oil needs to displace the old friction modifiers from the clutch faces and embed the new ones, can take 700-1000km.

If a 15w-40 engine oil is specced, any decent 75w-90 MTF will work.
Replaced the g/box oil in my gf's Courier a few weeks back with Syntrax and the cold shifts were immediately better, hot marginally.

**Dougal** · 12th October 2014, 04:45 PM

Originally Posted by rick130

The new oil needs to displace the old friction modifiers from the clutch faces and embed the new ones, can take 700-1000km.

If a 15w-40 engine oil is specced, any decent 75w-90 MTF will work.
Replaced the g/box oil in my gf's Courier a few weeks back with Syntrax and the cold shifts were immediately better, hot marginally.

My ~1986 MSA-5P sticker says 15w40.
My ~1992 MSA-5G sticker says 5w30.

*edit*
I run VMX80 in the MSA-5G with good results on Rick's suggestion, it's a good match for the 5w30 viscosity wise. I didn't experiment with oils in the 5P.

**Vern** · 12th October 2014, 04:50 PM

Well there is my problem dougal, I ran a gearbox oil in it. Will drain it tomorrow and put some good oil in it😊

**bee utey** · 12th October 2014, 04:56 PM

Originally Posted by rick130

The new oil needs to displace the old friction modifiers from the clutch faces and embed the new ones, can take 700-1000km.

Quite possibly, but I have different experiences. E.g. A bloke that drove his Cruiser from Perth to Adelaide came to me with shockingly poor shifts in a reco box. I drained and refilled it with engine oil and the shifts were loads better within the first 2km. Undoubtedly it could further improve but the change was immediately noticeable.

**rick130** · 12th October 2014, 06:13 PM

Originally Posted by bee utey

Quite possibly, but I have different experiences. E.g. A bloke that drove his Cruiser from Perth to Adelaide came to me with shockingly poor shifts in a reco box. I drained and refilled it with engine oil and the shifts were loads better within the first 2km. Undoubtedly it could further improve but the change was immediately noticeable.

Yep, it can be that fast too, experienced that myself, but it can also take a few km, just depends on the oil, fm's used, synchro surfaces, etc.

No hard and fast rules.

**Vern** · 12th October 2014, 06:27 PM

I think I'm running an 80-90w oil

**isuzurover** · 12th October 2014, 06:31 PM

Originally Posted by Vern

I think I'm running an 80-90w oil

Well that would explain it!!! Lucky the isuzu boxes aren't as fragile as landy boxes...

**Vern** · 12th October 2014, 06:33 PM

So best value for money oil to run would be?

**BadCo.** · 12th October 2014, 07:37 PM

Originally Posted by Vern

So best value for money oil to run would be?

Best value you say?

Try this Gulf Western Top Dog XDO Engine Oil - 20 Litre, 15W-40 - Supercheap Auto

On special you should be able to get it for under a hundred?

**steveG** · 12th October 2014, 07:39 PM

I'd throw some engine oil in it for starters to flush the other stuff out. Run it like that until you do your next engine oil change.
That way if there's a leak (being an unknown box) you're not throwing out good stuff when you sort the leak out.

Steve

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