Help for the New Guy

[Augi]

I just bought an 86 M-998. Awesome truck! It's been sitting for a long time so I have some work cut out for me.

I have found just about everything I need in the various TM's, but I can't seem to figure out what is supposed to be plugged into the open connector in the attached photos. Can someone tell me? There is no obvious dangling wire. The connector looks like it's coming out of the side of the head. (this is a 6.2/3-speed).


Oh, also I think the t-case (218 ) is on the way out. I'm in the process of changing all the fluids and the t-case fluid is cloudy with fine metal particulate. When driving 55, after 5 or 10 minutes I'll get a loud grinding noise like gear teeth slipping. I immediately let off the gas and the grinding stays til I'm stopped or almost stopped. If I start up again the grinding is gone for a while. When driving 50 it takes much longer til it starts grinding (20-30 min). I think it may be load based because it did it more when going up hills. I don't know if I was losing power to the wheels because I let off the gas and stopped every time it started making noise.

Has anyone heard of something like this before?

BTW I found all this out because I had to drive the truck 3 hours from where I bought it to where I live. Now it's off the road so I can work on it

Thanks,
Augi

 

[srodocker]

welcome aboard. we need some full pics of the hmmwv! as i dont know anything about the hmmwv i cant hhelp sorry

 

[Augi]

I'll post some more pictures of the truck in the next week or two.

I forgot to add: the plate with the HL/H/N/L positions for the t-case shift lever is missing. When I picked up the truck it was in high-lock. I drove it for 75mi on the highway before I figured it out and unlocked it.


Augi

 

[bratpackdad]

You knew that was coming.

Welcome to SS

 

[Haasino]

Augi,

Welcome aboard! You've come to the right place... I'm a new Humvee owner myself, and this board as well as G503.com has helped me gain a wealth of knowledge regarding these trucks.

As far as the photos you posted, that metal post is the Glow Plug Controller... that, coupled with the starter box that's under the dashboard, regulate the glowplugs for cold starting the Humvee. There should be a round plastic cap with several wires running to it that plugs into the top of that post. I've snapped two photos of the GPC and plug from my truck to give you an example... might just be as simple as looking around nearby for the unplugged cap.

As far as the grinding, I can't help you there unfortunately... but if you're in the Sacramento area, I can refer you to a great local mechanic who has experience working on Humvees now... thanks to me, lol!

Oh, and

 

[still standing still cyco]

welcome Augie...and it looks like the wires to the cap your missing mite be lying at the base of your Glowplug Controller, from the looks of your pic.... where in cali are you? spent almost 4yrs in socal... dumbest thing i ever did was to move back here from there...

 

[Augi]

I found the glow plug harness tucked under some other wires right there by the controller... Thanks for the help guys. Haven't hooked it up yet because I am troubleshooting some other stuff atm.

I've attached some pictures of the truck, and some pictures of the driver foot well. The brake light switch is a replacement part, but it seems to be backwards. If I have it mounted in the position shown (which the TM shows as the correct position) the brake lights are always on and go out when you press the pedal. The switch lever is spring loaded toward the front of the vehicle, but the connecting link to the brake pedal holds it rearward.

The switch is normally open, so when it is in the forward position it is open, and in the rearward position it is closed.

The brake pedal holds the switch rearward (contacts closed, lights on) and when you depress the pedal it moves it forward(contacts open, lights off).

I can't install the switch 180degrees out because the connecting link to the brake pedal will not reach.

Have I got a backwards switch?


Thanks,
Augi

 

[papakb]

Augi,

Welcome to both the Steel Soldiers and G503 sites. probably the best places to get answers to your HMMWV questions. Having been a San Jose owner for almost 10 years now I'd be glad to help when you get started.

My first suggestion is to stop driving it until you identify the source of the grinding. It isn't a normal sound. It looks like you've got a pretty nice area to work on it so get it up on stands and run it until you hear your noise then get under it and identify the source. Start disconnecting drive lines and see if when goes away.

The original M998s had a rear driveline brake that's as close to worthless as you could get. It's a manually operated caliper that clamps on a disc to E brake the vehicle. On mine if I got it tight enough to actually do anything the pads needed to be adjusted so tightly they warped the rotor in about 15 minutes. After 2 rotors I went to the ungraded "dual pull" style ebrake.

Most of the M998 manuals can be downloaded and my second suggestion would be to get a copy of the -10, -20, and -34 & P manuals and start going thru them when you have time. I can put it all on a CD for you if that's easier. Let me know.

April 18th - 25th is the MVCC Tower Park meet in Lodi. There'll be several HMMWV owners around (and parts dealers) that would be happy to take a new owner under their wings and help you out. There are probably 20 of us between San Jose and Grass Valley.

Kurt Lesser

 

[Augi]

Thanks for the warm welcome guys!

I have all the TM's for the m998 series and the up-armored humvee's electronically, so I'm set on that front. I appreciate the offer though.

This is a pretty good truck that I've got here. The only major issue seems to be the t-case, which I bet I can get cheap since the 218's all got taken out in favor of the 242's.

Eventually I'd like to go the the 4L80/242 combo, but I'll keep the TH400 for now. I need to figure out how to get the the engine speed sensor mounted to my 6.2 (can I drill and tap the block to mount it in the same place as on the 6.5?) The throttle position sensor should be easier.

Otherwise, it needs:

-belts
-glow plugs
-the fording lever doesn't seem to actuate the fan clutch (who knows if the drive -train gets pressurized?)
-the cluster backlights don't come on
-brake light switch needs replacing
-the oil pressure gauge shows 25psi all the time
-the halfshaft boots are starting to crack (one is torn)
-it may need the idler and pitman done (probably not immediately though)
-some of the insulation on the wiring is starting to crack and I may try to re-wrap some of it
-the rubber that goes on top of the firewall to support the hood and the rubber that goes on the hood lift rings needs replacing

I also need to check the geared hubs to make sure they have the late captive nut and washer and I'll go to 12 bolt rims with radials.

I've got a set of x-doors with the factory supplemental steel plate bolted to the outer skin that I'd like to sell or trade for a set of regular x-doors to save on weight.

Actually the driveshaft parking brake is in perfect condition. The rotor is flat and the brake holds the truck when shifted into drive at an idle per the TM test procedure.

Its been a California truck for the past 10 years and I bet the USMC had it in some desert during its service too, because its almost entirely rust free.

I'm really looking forward to getting it back tip top.

Edit: Also, for you California guys, who do you use to insure your truck? My insurance company won't do it so I need to find someone else. I have a 6digit VIN (the truck SN).

Augi

 

[emmado22]

Check to make sure the Glow Plug Controller matches the Control Box. There are several threads on this on here and the G503.

Get a new brake switch.. You might have part of an A2 brake switch assembly in there. They are on ebay all the time.

I love my M998.

 

[WillWagner]

Welcome Augie! Where in Ca are you? That wasn't over in Arcadia behind Gary Hill Auto was it?

 

[Augi]

I am in San Luis Obispo. The truck was in Tulare for a long time, but I found it in SW Colorado, where it was for the past year or two.

 

[Augi]

So I have been looking at my glow plug controller and PCB box... I have a box with a yellow sticker, but it is made by SSI not KDS.

It is identical to this one: HMMWV PCB Ignition Control Box Likely INOP! SSI - eBay (item 360141339212 end time Feb-10-11 17:10:24 PST)

My glow plug controller does not have the yellow band and the data plate is worn off, so I can't tell who made it.

Do I have a mismatch of components? Seems like when people talk about yellow vs green stickers they are talking about KDS parts.

Thanks,
Augi

 

[TedG]

HI Augi,

Welcome to the site and you have a good looking original M998. It looks nice and clean.

Bite the bullet and buy a new KDS controller (either green label or yellow with yellow gpc). Then replace all glow plugs with new regulated non swelling (do not by kashcar ones for they do break) and then get or make a grounding harness. Clean all grounds and test for good continuity.

Everything you mentioned can be bought on epay or post want ads here or on g503. Shop the stores on epay for the odd ball things like the insulation, etc.

Regards,

 

[gem1410]

did you ever find out what the grinding noise is--I have the same noise--how did you fix it--thanks

 

[Augi]

did you ever find out what the grinding noise is--I have the same noise--how did you fix it--thanks

Yes I did I'm sheepish to admit it but it was the fan coming on. That's why I felt like it was losing power too.

When I bought the truck the doghouse was not secure so I was getting a lot more engine noise in the cabin. Also someone had spent a lot of time sitting on the radiator so all the fins were bent over. I would drive 50 - 55 mph and the fan would kick on every 10 min or so because of the reduced airflow through the radiator. Obviously going uphill made it worse.

So first I secured the doghouse and it got much quieter. Then I took a screwdriver and straightened out every ****ed fin on the radiator. The engine temp dropped considerably. Now the temp basically never goes over 200 and the fan never comes on except for hotter summer days, even on a long uphill pull.


Augi

 

[17 Legion]

The clutch fan is loud! Thing is, I never noticed this noise until I was driving on road here in the States. Now it seems normal to hear it activate.

 

[actionpaintball]

X2 on the GREEN KDS. I also highly reccommend cleaning all grounds and running an auxillary ground harness, basically making sure the body, chassis, engine (alternator), dash, control box, are properly grounded.