Project 1990 Trooper

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Project 1990 Trooper

Postby Zenit » Wed Apr 12, 2017 3:15 am

Picked up this guy for a very low price last week. Very clean, with only 107k miles, no rust and very clean interior. 1990 Trooper with 5 speed manual, came with a stack of maintenance records from previous owner. Issue that I've discovered so far: transmission whines in all gears other than 4th, vacuum hoses are cracked, idle is weird, and temperature gauge behaves strange. Also looks like it is leaking oil from distributor and valve cover gasket. I picked up a replacement transmission from car dismantler yard (80k miles on the new one), and will probably have it swapped out by a mechanic. The other stuff I will attempt to tackle myself. Anything else major I should check for? Is there anything I should check on the new transmission before making the swap?

I will have them replace the clutch when swapping transmission. Are clutches made by Luk any good? Should I also put on a new flywheel (also Luk) and rear main seal when doing the transmission/clutch?
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Re: Project 1990 Trooper

Postby itsmehb » Wed Apr 12, 2017 7:38 am

Looks like you have a good start towards restoring your Trooper. You must be on the west coast. Troopers around most of the rest of the country are getting hard to find, at least here in Texas they are. You can get most all the oem parts you will need from our own Isuzu guru here on our forum JLEMOND, including the oem seal for the distributer. Don't know much about clutches as I haven't had to replace mine yet, but I see exedy mentioned a lot on here. Also be careful if you get a new flywheel that it's not a cheap one from China. Your better off getting an oem one. While you have the valve cover off check the head torque. Just take your torque wrench and in the direction spelled in the manual try tightening the head bolts. I'm thinking the torque setting is somewhere around 72 to 75 ft. lbs. Also time to set the valves. Intake .008 and exhaust .0010 thousandth. Might be a ggod time to check your timing belt also. Also the cooling system on the four cylinder as they do not respond well to over heating issues. Head gaskets tend to fail or worse the head itself will crack. Good luck with your new Trooper. I've also seen mentioned here about flywheel bolts and locktite, so check that out before you replace your flywheel.
1990 Amigo, 2.3 5 speed (sold)
1991 Pick up (long gone)
2000 Amigo, 2.2 5 speed(sold)
1985 Trooper 1.9 4 speed (sent back to KS)
1989 Trooper RS 2.6 5 spd. Red

We get too soon old and too late smart!
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Re: Project 1990 Trooper

Postby MarkB.NV » Wed Apr 12, 2017 9:30 pm

Exedy is typically cited as best of class for clutches. If your flywheel is beyond re-use, then shop hard for a decent Japanese or US manufactured unit. If not terribly worn see if your local machine shop can just re-surface the old one.

Flywheel bolts are sinlge use only item and contact JLEMOND for a full set of new OEM bolts. And like Harry said, be sure to use blue loctite on the the threads to prevent oil leaks.

Highly recommend you plan on flushing and refilling the cooling system, maybe twice. Its cheap insurance against the overheating thing -which nearly always leads to head gasket failure and/or cracked head.

That little 4ZE1 motor is a decent power plant and don't let anybody tell you otherwise. However, it is very finicky about them damn vacuum lines, and about the sensors and wiring. This makes 'em somewhat temperamental after nearly 30 years on the road.

Lucky for you, you've come to the Planet where you can get the best guidance around. :)

This thread has some info on them vac lines and should help you get things sorted

Fluid quantities:
Manual 5 speed, 2.95 L (3.2 US Quarts) SAE5W-30 ... or 10W-30
Transfer case, 1.45 L (1.6 US Quarts) SAE5W-30 ... or 10W-30

Front Axle: 1.5 L (1.7 US Quarts) using SAE90 typically ... or Mobil-1 75w-90
Rear Axle: 1.8 L (2.0 US Quarts) using SAE90 typically ... or Mobil-1 75w-90

Fuel tank: 21.9 US Gallons

Cooling System: 8.0 L (2.11 US Gallons)

Member squatch posted a pic of the trans when he was updating the vent and vent lines - and I stole this pic from him. Arrows point to fill plugs.


For the trans ... probably best to drain and replace the oil in there. Be sure to use a decent engine oil - either Mobil-1, Rotella, or Delo 400 - in the 10w-30 weight.
There are two drain plugs there, one on the trans and one on the xfer case ... both on the bottom.
Likewise there are two fill plugs, one for trans and one for xfer case ... both on passenger side.
Make sure you can get the fill plug off first - otherwise you'll drain it and then not be able to refill. :(

Also, if you have good google skilz you can find the Factory Service Manual (FSM) for an '88 on the interwebs in PDF format. And nothing beats the FSM for these trucks.

Post up more pics when you get the chance ... we do love some fresh Trooper [email protected] :)

And ... Welcome to the Planet, FNG !!!
(favorite new guy)
Tan 1986 Trooper, 2.6 / 5 speed, 173K mi.

White 1984 Trooper, 1.9 / 4 speed, 89K mi.

Sold ... Silver 1990 Trooper, 4 cyl, 5 speed
Sold ... Blue 1989 Trooper, 4 cyl, 5 speed
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Re: Project 1990 Trooper

Postby Zenit » Thu Apr 13, 2017 2:56 am

thank you for the awesome info, will look into this stuff the coming weekend!

The vacuum lines are definitely old, brittle and cracked on this thing, something to replace this weekend. Also the upper radiator hose looks a bit swollen on the radiator side. Is this something that indicates poor flow through the radiator, or just old hose that should be replaced?
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