Database on Isuzu engine/Landrover gearbox combos

[C H T]

Isuzurover has suggested starting a data base on Isuzu engines (turbo and naturally aspirated) and Landrover gearboxes - with partricular reference to how gearboxes have stood up to the engines.

How about listing the following:

Vehicle and weight
Engine turbo or N/A tweaked or standard (ref to Boost/fuel would be useful)
Gearbox including suffix/year eg early or late suffix R380
Kms without problems
Nature of any failures and probable cause and or circumstances of failure eg towing heavy trailer
Transfer case ratio

Christopher

[Dougal]

Looks like I get to start.:)

Vehicle: 85 Rangerover. 2300kg empty
Engine is a factory 4BD1T, ran 220,000km at mostly stock power levels, last 8,000km at +50% torque.
Boost is 20psi, no intercooler (yet) and fueled enough to hit 750C EGT's when asked.
Gearbox for the first 220,000km was Isuzu MSA-5P from an Isuzu NPR. Bearings feel rough when turned by hand due to running without oil. Not noticable while driving.
8,000km ago an MSA-5G gearbox was installed to get more suitable ratios, this gearbox is secondhand with approx 250,000km use. Still tight, smooth and quiet.

The MSA-5P was run with a 1.2:1 ratio LT230, this was swapped for a 1:1.003 ratio LT230 shortly before the MSA-5G gearbox was installed.
Dropping the cruising rpm from 2500 to 2000rpm made a huge difference in noise and comfort. Fuel economy improved too.

No failures, but they get loud when out of oil.

[isuzurover]

Thanks for getting this going Chris!


Vehicle and weight: County 110, 1987, 1.9T (as usually driven)
Engine: 4BD1 (currently na, but not for much longer)
Gearbox: Factory LT85
Kms without problems: 240 000 (rebuild) / 100 000 (since rebuild)
Failure: Failure (loss of drive) at 240k km. PO sent box to MD for rebuild. Believe the problem was stripped mainshaft splines. New mainshaft, 5th gear, and many new internals fitted.
Transfer case ratio 1.003:1

Can I suggest we each post our own vehicle (rather than a mate's we don't have complete info for). Though I will try and call the mate of mine who has killed 6 or 7 R380's - to get full info - as he doesn't do forums.

[Larns]

Veh - Defender 90
Weight - Hard to say.........
Engine -4BD1, was a N/A but have converted to non-gated garrett
Tweaks - Manderal custom 3" exhaust
Tweaks to come - T25 turbo, custom intercooler, custom grind cam
Gearbox - R380, suffix "J" 7k old now
Km's / Probs -snapped the original mainshaft at 3k, I personaly think it
was an existing problem with the old shaft an the suzi found it!

Nature of G/box work - I built the car for it's towing capasity, in the top end I need to be able to tow a big boat all day and then launch it. The Isuzu was the only choice. I originaly had the LT95, just got sick of the ratios!!! I could take off with a boat in second. Needless to say I tow in fith..............

Transfer case - I now have a LT230 with the 1:1 ratios, cruise on 100 @ 2000rpm.

Fuel econ - I get around the 10Lt/100km, although lately a bit better @ around 9lt/100km

:twobeers:

[justinc]

My turn...:)

1992 RRC, 520,000km old N/A 4BD1 ex 1988 110 county. Now turboed and intercooled, air to air front mounted. Using Garret TB25 watercooled unit on centre mount exhaust manifold. Broken 3 ZF 4HP22's, fitted a LT95, transfer case thrust washers wore out 3 times in 20K, now fittted ex perentie 6X6 LT 95 with all the taper roller conversion etc. Now not concerned abou the transmission at all:):) All this with the fuel wound up to give me 640deg up hills in 4th converter lockup. No wonder the lock up clutch material was stripped off it...

I am now running conservative fuelling due to fuel $$$, up a long hill towing a 1000kg camper trailer in top gear I can exceed 520deg JUST. Without a load, I run out of hill before it gets that high.:cool: I can easily pull up hills in top gear with 33" tyres all day, and will easily see the fuel governor in 4th on the flat or any light gradient. My fuel consumption is in the region of 11 to 14 litres / 100km, and I have 15psi at the manifold max boost, wastegate disconnected.

I only have 1 weakpoint now. The clutch.:mad: Not slipping yet, but I can see myself upgrading to the 6X6 spec pressure plate soon.:(

I haven't dynoed the thing yet, but as I drive plenty of chipped Defenders and Disco Td5's, I would say mine is at least 20% more torquier and must be in the region of 450 to 500Nm. Especially due to the fact I am also on average 2" taller in tyres....:twisted:

JC

[C H T]

Now for my vehicle:

Vehicle: 99 Defender ex 300 Tdi 3.1 tonnes loaded for a trip
Engine: Factory 4BD1T running 12 psi boost with small increase in fuelling
Gearbox: Late suffix large layshaft bearing R380
Circa 21000 kms with no problems
Trannsfer Case Ratio: 1.2:1

Have towed up to about 2.8 tonnes without any difficulties - easily cruising at highway speeds.

Fuel consumption between 11.9lts/100ks (8.4kms/lt 23.68mpg) and 15.7lts/100ks (6.38 Kms/lt 18mpg) towing average about 19mpg (6.74kms/lt 14.8lts/100ks)

Christopher

[DRanged]

Vehicle 85 Range Rover 510hours both engine and box

Engine
Isuzu 4BD1 with factory turbo rebuild kit, TD5 turbo custom manifold 2 1/2'' straight thru exhaust. Top mount I/Cooler with ''Mad max'' style bonnet scoop, running 15psi boost at manifold, refuelled pulling 600 deg full load up hill.

G/box & Trans
Suffix J R380 running through LT230 1.22.1 high range, Maxidrive 57:1 low range

Diffs
4:11 spanish reverse helix running on 35'' Creepys Maxidrive shafts and lockers + CV anti exploder rings

Weight
2440kg unladin

No problems on road other than the spigot bearing is getting worn I think.
Off road have twisted a couple of rear tailshafts, destroyed 1 rear CWP. Sheared 1 front outer shaft.

Cruises happily on 100km/h at about 2000 - 2100
Torque is unknown but has ample supplies of it. Towing is no problem, but I am very gentle on the gearbox. Fuel economy unknown but is fairly good for the vehicles performance.

Justin

[EchiDna]

88 110 4BD1 (post factory Turboed, 2 owners ago) with taper roller bearing conversion to the original LT85
35*12.5's cooper STT's
4.11's front and rear

approx 320k on the drive train - nothing broken since I got it...

not sure what the clutch is as I haven't had it apart since purchase :)

Plans: I/C, and use the blardy thing a lot more than currently!!

[Blknight.aus]

you want the military stuff I get to see fubared or just pers stuff?

[C H T]

Dave

It would be helpful to have some info on miiltary gearbox failures and probable cause (apart form the nut behind the wheel!!!)

[Bush65]

84 rangie (originally 4 door) converted to 2 door/seat cab with small, low camper back (front and rear overhangs are less than stock, back is lower than cab roof). Weight unknown at this stage (incomplete).

Isuzu 4BD1-T, unknown km's, condition excellent, balanced, boost pressure ~30psi (expected), 3" exhaust, air to water intercooler, modified fueling.

Isuzu MXA-6R gearbox, unknown km's - stronger than stock box used with 4BD1-T, and stronger than LT95.

Clutch has Isuzu pressure plate as used with 4BD1-T, clutch plate made to suit the larger input shaft of the MXA-6R.

Transfer case atlas II, high range 1:1, low range 5:1

Diff ratio 4.1:1 (not rover).

[Blknight.aus]

Dave

It would be helpful to have some info on miiltary gearbox failures and probable cause (apart form the nut behind the wheel!!!)

well that pretty much eliminates 99% of the ones I see...

the gearboxes last soo much better when they have oil in them or when you change gears using that pedal on the left....

common failures are

syncro wear- speed/snap/race shifting, trying to no clutch shift ( since I almost always double declutch as soon as one of these turn up I tend to send it back after a test drive with "no fault found, further driver training may be required if fault persists"

failed bearings- excessive idling to charge batteries on ffr's/low speed crawling/wrong oil added by drivers during non techs

Failed Tcase gears- not following the instructions for Tcase use/mis adjustment of selectors during installation of the box

Failed center Diff, generally abuse.

Ive seen very few failures that cant be tracked back to human neglect/ignorance/stupidity.

[rar110]

Vehicle and weight
Perentie 110 (formerly FFR now 4 door wagon), gal chassis probably makes it a bit heavier than standard 110, but not much.

Engine
original N/A now with Garrett GT28R ballbearing turbo fitted to top mount Isuzu turbo manifold and custom 3 inch mandrell/lukey exhaust, boost set at 12psi. I plan to fit a FMIC sometime down the track.

Gearbox including suffix/year eg early or late suffix R380
LT95 with .996 transfer. I don't know if its original or not. It doesn't have the perentie intermediate shaft with the nut at the back. However, it does have the perentie style high/low range selector stick.

Kms without problems
Vehicle has about 170,000km, gearbox is unknown, I've had it back on the road for 1.5 years, done about 20,000km - generally trouble free. Only problem has been rubbish in fuel tank causing new lift pump to fail. Gearbox is very noisy but works fine. Ratios are ok but could be better. I am considering a R380 down the track to fix noise/ratio issues or alternatively get 255/85s. Noise is the main problem. I wouldn't bother changing boxes if I could fix that.

[rovercare]

Vehicle and weight
120" 292.oooklms, 2200kg
https://www.aulro.com/afvb/images/imported/2008/07/922.jpg

Gearbox
LT95

Nature of any failures and probable cause and or circumstances of failure
Intermediate shaft, hard face gone, damaged thrust washers..........normal LT95 stuff:D
https://www.aulro.com/afvb/images/imported/2008/07/923.jpg

http://www.aulro.com/afvb/technical-chatter/58218-lt95-standard-tapered-roller.html

Transfer case ratio
0.996:1

[Bearman]

Morning everyone
Heres some data for my vehicle
Vehicle...Originally 1986 110 county V8 dual cab with LT85/LT230 combination now transformed to 4BD1/LT95 with gal army chassis.
Weight...Around 2500kg with Isuzu,winch and bullbar
Engine....4BD1 N/A fitted with Garrett TO3 watercooled and wastegated.10psi boost and mild fuel increase.Runs up to 600C pulling up hills. Gives 10-12L/100k.
Gearbox..LT95 "C" series box/transfer fitted with .996 ratio tapered roller intermediate shaft assembly. Maxidrive locker in rear diff. 4 pinion front diff centre.
Problems...None. Has done approx 700k on combination.Had injectors cleaned twice and was told by dieseltec they really didnt need cleaning.Absolutely no problems with LT95-I love it.Its the only box that will stand up to the grunt of the Isuzu.Thats why the army uses it

[Dougal]

Absolutely no problems with LT95-I love it.Its the only box that will stand up to the grunt of the Isuzu.Thats why the army uses it

The Isuzu boxes are an excellent option too. But they're not yet the bolt in option that the LT95 is.

[JDNSW]

Somehow missed this thread earlier!

1986 110 County. Original LT95, 4BD1 original, 465,000km.

Drive train repairs - about 90,000km the pins joining the two halves of the transfer selector dog clutch broke, requiring the idler gear assembly to be replaced. At the same time thrust washers in the centre diff were found to be badly worn and replaced. About 120,000km front diff centre replaced with four planet one, as the hole for the cross shaft was flogging out.

About 250,000 gearbox became noisy, replaced all bearings and seals, but the only bearing needing replacing was the input shaft bearing.

Currently, the gearbox is a little noisy, but pretty much drowned out by the engine. I have the idling set high enough to prevent excessive gear chatter when idling. Load varies from empty to nine bodies plus luggage, occasionally towing a tandem trailer with an estimated load up to 2500kg, but rarely for more than a couple of hundred kilometres.

John

[rovercare]

. Has done approx 700k on combination.it

How's the county holding up?:eek:

I think we need some pics, can email them to me and I'l post them up if you like:D