Calling all people smarter then me

[FreeLantz]

Evening folks. This is my very first thread on this new-fangled inter-net machine, so be gentle.
Anyway, i have a vaguely outdoor related mechanical question to ask. My hunting truck, a beat up 2001 chevy half ton, is kinda driving me insane, and i hope someone can help. Heres the story.
The transfer case started making noise. Common in these vintage with the autotrac t-cases i've been told as the chain stretches and slaps around in the case. So i swapped it out, and decided to do some other things while it was parked. I parked the truck in the shop in June, and i had room and time on my side so i poked on it here and there and whenever. Then my dad needed the hoist for a bit so i parked the truck out in a shed on the farm. Sometime in between, the battery went stone dead, like nothing at all. So i boosted it, and man my dash lit up like a christmas tree. Half the lights were blinking, the other half were on steady. The four way lights started blinking on their own. When i turned on the stereo, my high beams would come on. Half the numbers in the odometer read 888, while the other half had actual numbers. The door chime would come on randomly, but making a weird, long tone.
I know what you are thinking....fried the computer. But after a bit of this nonsence, it all kinda stopped being weird, and the truck was idleing very nice, and all seemed ok. I went for a burn down the road, and the speedo stopped working, and the truck won't shift out of first gear. An ex-chev mechanic i work with said maybe it's the vehicle speed sensor on the back of the transfer case, coupled with a dead short in the battery. Kinda makes sense i suppose. I dunno, I swing a hammer and turn big wrenches for a living, these computer thingy's are foreign to me. This ever happen to anyone else? I need this thing operational for Novemeber!

[lannie]

I would check the ground strap or ground circuit.
Put a booster cable between the ground post(battery) and the engine block.

[winger7mm]

The only thing iv had with my chev, is a few times in last couple years the speedo has quit. Shut the truck off and start back up good as new.

And btw a 2001 is by far a relic hunting truck lmao, also the older the better WAY easier to figure out and to work on lol

[Sneeze]

I would look at it as two problems.

1) Speedo toast
2) Not shifting out of first


Start with the serious problem of the tranny shifting first and maybe when its fixed your speedo starts working!

The first thing I would do is have the computer scanned for trouble codes. My guess is there is one there that will pin point your problem.

My immediate guess at a problem would be a NSBU or Neutral Position switch. You probably smacked it or messed with it while doing the T-case.

Speedo could be a stepper motor that decided it was tired of life.

[backpacker]

This will sound silly but I think this might work for you. When your speedo does the dead thing and the tranny won't shift out of low gear, slap the top of your dash in front of the steering wheel. My /95 F-150 does these things as well and all it is , is a short somewhere on those metallic tape type strips that are part of the dash wiring harness. Let me know if this helps, I am curious now,lol.

[Dacotensis]

Your rear differential will blow up in about 1000kms or less.

Same thing happened to my 97.
It now has a limited slip auburn diff. I like it much better.

[FreeLantz]

Originally Posted by Dacotensis

Your rear differential will blow up in about 1000kms or less.

Same thing happened to my 97.
It now has a limited slip auburn diff. I like it much better.

Wow. Straight for the throat eh? lol Nope she has a solid rear end, unlike my ex-wife BOOOOM!! hehehehe. Auburn clutch packs, that are now worn right out, were one of the first things i did a couple years ago.

Thanks for the replys boys. I know the transmission is in good shape, it's fairly new and the oil is in good shape and never once slipped. I'm confident it's some mystrious electrical mumbo-jumbo taking me for a ride. I'll try the trick lannie suggested, great idea actually thanks, then i'll smack the dash backpacker

Also Sneeze, I have a scanner, and the only codes coming up are O2 sensor related....mostly because i accidently left the cats on a hillside in the bush one day and never replaced them. What's an NSBU? I have a feeling the lack of shifting and the speedo not working are tied together some how.

Winger, I'm seriously contemplating throwing this truck in the back 40 and finding an older ford or TBI chevy. They last forever it seems.

I should also say the previous owner flashed the computer. Maybe he meant he showed the computer his junk, i can't be sure.

[Fisherpeak]

I don`t know if this will help but there is a wire on the top of the tranny that,if it is disconnected will cause all kinda hell like you are having.Happened to me once on a 94 Silverado.

[russ]

Originally Posted by FreeLantz

Evening folks. This is my very first thread on this new-fangled inter-net machine, so be gentle.
Anyway, i have a vaguely outdoor related mechanical question to ask. My hunting truck, a beat up 2001 chevy half ton, is kinda driving me insane, and i hope someone can help. Heres the story.
The transfer case started making noise. Common in these vintage with the autotrac t-cases i've been told as the chain stretches and slaps around in the case. So i swapped it out, and decided to do some other things while it was parked. I parked the truck in the shop in June, and i had room and time on my side so i poked on it here and there and whenever. Then my dad needed the hoist for a bit so i parked the truck out in a shed on the farm. Sometime in between, the battery went stone dead, like nothing at all. So i boosted it, and man my dash lit up like a christmas tree. Half the lights were blinking, the other half were on steady. The four way lights started blinking on their own. When i turned on the stereo, my high beams would come on. Half the numbers in the odometer read 888, while the other half had actual numbers. The door chime would come on randomly, but making a weird, long tone.
I know what you are thinking....fried the computer. But after a bit of this nonsence, it all kinda stopped being weird, and the truck was idleing very nice, and all seemed ok. I went for a burn down the road, and the speedo stopped working, and the truck won't shift out of first gear. An ex-chev mechanic i work with said maybe it's the vehicle speed sensor on the back of the transfer case, coupled with a dead short in the battery. Kinda makes sense i suppose. I dunno, I swing a hammer and turn big wrenches for a living, these computer thingy's are foreign to me. This ever happen to anyone else? I need this thing operational for Novemeber!

Check the charging system first, ie - battery, alternator, starter. Sounds like the battery might be pooched. If it's not that, mice may have had their way with your underhood fuse block. Remove it and check for chewed up wires underneath and pull the connectors and check for corrosion. Repair the wires & clean the corrosion.

BTW, as far as Auto transfer cases have a chain stretch problem, honest opinion here but every time I've seen that problem it's user induced. Tires need to be rotated on the indicated service interval and replaced in sets of 4.

[Freedom55]

I agree with the mouse theory.

[FreeLantz]

Originally Posted by russ

Check the charging system first, ie - battery, alternator, starter. Sounds like the battery might be pooched. If it's not that, mice may have had their way with your underhood fuse block. Remove it and check for chewed up wires underneath and pull the connectors and check for corrosion. Repair the wires & clean the corrosion.

BTW, as far as Auto transfer cases have a chain stretch problem, honest opinion here but every time I've seen that problem it's user induced. Tires need to be rotated on the indicated service interval and replaced in sets of 4.

Of course it's user induced!! Duh! lol. I rotate tires whenever they get flat, and buy the cheapest single tires from junk yards, because its a beater, and i treat it as such. That has zero influence on the electrical issue.

Couldn't find any trace of mice living under the computer. Everything seems ok there.

Fisherpeak: I'll check the wiring this weekend, thanks.

Fired it up after night shift, did a similar loopy little crazy spaz out thing again, then settled down. I did find a ground strap broken off behind the right rear cab mount. Replaced it this morning with heavy gauge welding cable....also smacked the top of the dash for good measure .....still no shifting, and speedo not working. New battery this weekend, and gonna replaced the vehicle speed switch, if i can find it.
Thanks for all your guys help! I'll let you know what i find!

[Sneeze]

Originally Posted by FreeLantz

Thanks for all your guys help! I'll let you know what i find!

Sneeze be cereal here -

Check the Neutral Position Switch!

[russ]

I never said a word about any of the computer modules (there's more than one BTW), I said check the under hood fuse block, that's on the drivers side, under the hood, mounted above the front wheel house, it is not a computer, it's a fuse block.

[gutline homestead]

I drive a 2000 chev.it was stolen before my time,it goes weird. it has to do with the damage that was done to the innards of the ignition chamber,when it got stolen ,most shops never repair that part.also will haveno low gear to start out ,no r.p.m. no gauges. Turn off, restart,hope..But like the man said.could be a bad ground strap. chev`s good for that.

[FreeLantz]

Originally Posted by Sneeze

Sneeze be cereal here -

Check the Neutral Position Switch!

I'm being super cereal here. That'll be the first thing i look at friday afternoon, after I play with the battery and ground straps some more. I thought the NPS just wouldn't allow the truck to start other than in neutral or park, though??? Anybody chiming in on this Vehicle Speed Switch doo-hicky?


russ...i feel you might be an arguer in real life. Are you a lawyer perhaps?

[lannie]

Originally Posted by FreeLantz

I'm being super cereal here. That'll be the first thing i look at friday afternoon, after I play with the battery and ground straps some more. I thought the NPS just wouldn't allow the truck to start other than in neutral or park, though??? Anybody chiming in on this Vehicle Speed Switch doo-hicky?


russ...i feel you might be an arguer in real life. Are you a lawyer perhaps?

Hows the truck?

[FreeLantz]

Havent been home long enough to look at it since friday. 3 kids in hockey eats up the ol' free time, hoping to hit it this weekend. Thanks for asking!!

[FreeLantz]

Soooo for any one curious, this is what i discovered.

I installed ground cables like crazy, running everywhere. Looks like medusa under the hood now.
I replaced the Vehicle Speed Sensor. Old one was busted.
I re-did some wiring that looked shady on the transmission.
I pulled the under hood fuse box out and inspected and cleaned. Found some burnt fuses, one for the 02 bank 1 one circuit. Nothing else really serious.
Attempted to look at the Neutral Position Switch, but got side tracked.
New battery.

Result: I can now manually shift from 1st to 2nd. If i attempt to shift to 3rd, it downshifts back to 1. If i leave it in Drive, it stays in 1st, won't shift at all.
My speedo is now pegged at 180km/hr, but i think i can fix that easily. I put it in 4 wheel drive and burnt around the farm for a bit and the service 4x4 light came on, and wouldn't let me take it out of 4 high. That went away real quick though. ABS light is on now as well.
On the brightside, no more flashing lights, or weird stuff happening electrically. Truck is actually running better than ever, aside from not shifting properly.

I'm sick of this thing. It's on Kijiji now, if i can't sell it, it looks like its gonna be a baggin wagon I guess. Maybe I'll turn it into a water hauler or something. Or something for my kids to bag around the farm in a couple years.

[50/50]

my 2001 went into safe mode (transmission), when 1 of the 2 speed sensors quit working. (on the back of the t case ). 1 controls the speedo , the other controls the shifting.

it also does the same funny electrical things when the battery goes dead.

[FreeLantz]

Originally Posted by 50/50

my 2001 went into safe mode (transmission), when 1 of the 2 speed sensors quit working. (on the back of the t case ). 1 controls the speedo , the other controls the shifting.

it also does the same funny electrical things when the battery goes dead.

So maybe both of those sensors have to be changed? I never thought of that. I'll give that a whirl. Thanks

[50/50]

The two sensors are identical. since the wiring harnesses are not long enough to simply switch , you must physically swap the sensors places .

When I did this my speedo quit but my tranny shifted properly . when I switched back , speedo worked but no shifting.

This was a 480le trans. you could have a 460 le if its a 1/2 ton.

[raab]

You by chance didnt mix up the positive and negative cables when you boosted it?

[FreeLantz]

Originally Posted by 50/50

The two sensors are identical. since the wiring harnesses are not long enough to simply switch , you must physically swap the sensors places .

When I did this my speedo quit but my tranny shifted properly . when I switched back , speedo worked but no shifting.

This was a 480le trans. you could have a 460 le if its a 1/2 ton.

By chance, I happen to have 2 spare sensors, sitting in the old t-case. But when i switched out the drivers side one, it didn't do anything but bury the speedo at 180km/h. Not sure what that means, but when i disconnected the battery and switched it back to the old sensor, it went back to zero. I'll try it anyway. Can't hurt. You are sure they are identical? One isn't normally open and the other normally closed or some crap like that?
Yeah it's a 4l60e, positive of that.


raab, i doubt i did that. The last (first, only) time i did that i blew the top off the battery and had to change my shorts lol. But anything is possible. I've been known to do dumb things in the past.

[raab]

Originally Posted by FreeLantz

By chance, I happen to have 2 spare sensors, sitting in the old t-case. But when i switched out the drivers side one, it didn't do anything but bury the speedo at 180km/h. Not sure what that means, but when i disconnected the battery and switched it back to the old sensor, it went back to zero. I'll try it anyway. Can't hurt. You are sure they are identical? One isn't normally open and the other normally closed or some crap like that?
Yeah it's a 4l60e, positive of that.


raab, i doubt i did that. The last (first, only) time i did that i blew the top off the battery and had to change my shorts lol. But anything is possible. I've been known to do dumb things in the past.

Yea it's an easy mistake to make, my sisters boyfriend did it a few years ago. Needless to say the car will start but it hasn't been driven since because of all the electrical issues. My bet is it a charging system problem or ECU. The ECU's are famous for going in the old chevs.

[Fordpilot83]

Originally Posted by lannie

I would check the ground strap or ground circuit.
Put a booster cable between the ground post(battery) and the engine block.

X2. Thats got poor grounding written on it

[FreeLantz]

So the truck is sold. I happened to sell it to an automotive instructor at NAIT, and he told me what the deal is. Apparently there's 3 Vehicle Speed Sensors on the truck. 2 on the back of the t-case, and one on the front output shaft. 2 of these 3 aren't working, whether that means the sensor or wiring or tone ring or whatever isn't doing it's job. Also causing problems is the ABS control unit, right on top of the brake hydraulic unit on the frame. That costs about $1000, unless you find one at a scrap yard and I guess that's unlikely.
I'm just happy to see tail lights. I was so happy I threw in a bunch of extras, including an entire complete, leak-free front diff and hubs and cv's. He did alright, and I have funds towards some awesome hunting stuff