3.9isuzu gbox conversion to nissan patrol box

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16th April 2009, 11:24 AM
isuzubob

Quote:

Originally Posted by garryseries3

So did you use the isuzu flywheel with your conversion???
Kindest regards
Garry

Remember if you go the Isuzu g/box route you'll need Isuzu (truck) flywheel housing, flywheel & starter.

Rob W
16th April 2009, 04:22 PM
garryseries3

Quote:

Originally Posted by isuzubob

Remember if you go the Isuzu g/box route you'll need Isuzu (truck) flywheel housing, flywheel & starter.

Rob W

Hi Rob yes I relise that maybe the case, I am really trying to get a idea of the pros and cons of different configurations that will go behind the isuzu in my 130, the effort required for fitment, cost and the longevity I can expect. So far from a gearbox longevity point of veiw it looks like isuzu then Lt95, then the late model R380 followed by the LT85. From a ease of fitting the LT95, LT 85 and a late model R380 may all be similar. The later requiring me to purchase an adaptor to fit up to the Isuzu. As for an Isuzu box there is the rear adaptor plate and intermeditate shaft in between the transfer case and isuzu box that needs fabrication.
Kindest regards
Garry
16th April 2009, 10:03 PM
rijidij

Quote:

Originally Posted by Dougal

There is a 3" aluminium plate which replaces the rear of the Isuzu box and bolts to the old LT77 rear casing. I have plans for a steel fabrication that will do it better in one hit.
There is an adapter shaft between the Isuzu gearbox output and the LT230.

Is the aluminium plate milled from one solid piece ?

Is the adapter shaft like, a short rod or heavy tube with splined sections welded to the ends ? If so, can you buy short splined sections (similar to when they replace the end of a prop shaft, only smaller), or do they have to be specially made.

My 120 has an Lt85 in unknown condition, and I have the 5 speed out of the truck which has only done 3k since full rebuild, so I might think of going down this path too. I could use the Lt230 off the 120, even if it needs some work.
17th April 2009, 04:40 AM
Dougal

Quote:

Originally Posted by rijidij

Is the aluminium plate milled from one solid piece ?

Is the adapter shaft like, a short rod or heavy tube with splined sections welded to the ends ? If so, can you buy short splined sections (similar to when they replace the end of a prop shaft, only smaller), or do they have to be specially made.

My 120 has an Lt85 in unknown condition, and I have the 5 speed out of the truck which has only done 3k since full rebuild, so I might think of going down this path too. I could use the Lt230 off the 120, even if it needs some work.

Yes the aluminium plate is machined from a solid piece, the shaft could be made from several pieces, but in the interests of strength I had mine made from tool steel approaching 2000MPa UTS. It takes about 2000Nm (torque required to spin wheels on dry tarmac with my current gearing) so strength was a concern.

But the aluminium plate isn't the best idea, a single fabrication has a lot of advantages. I just haven't finished designing one.
17th April 2009, 06:30 AM
rick130

Quote:

Originally Posted by Maggot4x4

Yep, the 2.8L Diesel and the 3.0L Petrol had alloy boxes and are junk.

The new 3.0L Diesel boxes have problems with 5th. The only decent one is from behind a 4.2/4.5/4.8L and even they strip 5th if you tow a lot.

The stripped spline issue was a production batch between '00 and '01, they should be out of circulation by now.
Our June '01 patrol has towed horses for at least 200,000km of its 300,000km life without any issue, and SWMBO thinks nothing of plonking it into 5th whenever it needs it. TD42T's don't like to rev, so its spent a lot of its towing life in 5th.
17th April 2009, 07:38 AM
Phil Stage 1

G'day all

Bush 65, what model gearbox is your 6 speed?

Thanks

Phil
17th April 2009, 02:16 PM
isuzurover

Quote:

Originally Posted by Phil Stage 1

G'day all

Bush 65, what model gearbox is your 6 speed?

Thanks

Phil

From another thread:

Quote:

Originally Posted by Bush65

My 6 speed (MXA-6R), wasn't originally behind a 4BD1.

The ratios are also different to any of the others in Dougal's list. I had written them down once upon a time.

1st is close enough to 5:1. 4th is 1:1, 5th and 6th are both overdrive.

When I get a chance, I will check them out so the list can be updated.
17th April 2009, 06:13 PM
Maggot4x4

Quote:

Originally Posted by rick130

The stripped spline issue was a production batch between '00 and '01, they should be out of circulation by now.
Our June '01 patrol has towed horses for at least 200,000km of its 300,000km life without any issue, and SWMBO thinks nothing of plonking it into 5th whenever it needs it. TD42T's don't like to rev, so its spent a lot of its towing life in 5th.

I have a mate that towed a move your self trailer from Brizzy to Hervey Bay behind a 2004 4.2 patrol and blew the box up (5th)
17th April 2009, 06:41 PM
Bush65

Quote:

Originally Posted by Phil Stage 1

G'day all

Bush 65, what model gearbox is your 6 speed?

Thanks

Phil

MXA-6R (I don't know year).
1st 4.987:1
2nd 2.870:1
3rd 1.684:1
4th 1.000:1
5th 0.728:1
6th 0.626:1
rev 4.774:1

If I remember, I will put it alongside an R380 on Sunday and take some pics.
17th April 2009, 06:51 PM
Dougal

Here are the ratios of mine. This one from a 92 Isuzu NPR Elf250.

MSA5G,
5.788:1
2.998:1
1.594:1
1.000:1
0.776:1
5.798:1

Interestingly the MXA5R shares 1,2,4,5&r gear ratios with John's 6 speed.
MXA5R
4.987:1
2.870:1
1.594:1
1.000:1
0.728:1
4.774:1

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