What's new
By:
Filters

1994 K3500 tow/work/camp truck

trekking_LC

trekking_LC

Active member
Joined
Dec 7, 2021
Member Number
4597
Messages
26
Bought a 1994 k3500 the other day, ya know… like the title says.

Not sure if there’s as much interest in these trucks anymore, but I’m going to be tinkering with this one for awhile so I might as well document it.
I’m notoriously bad at maintaining “build” threads so. Whatever.

B355CB41-ADA2-4FEF-B7CC-2C910F13D4AC.jpeg


Basically as bought, though I removed the Warn bumper brush guard, which is visible on the left. It was all floppy.
 
Specs are 454 with a touch over 200k, 4L80, currently unidentifiable tcase (aka haven’t looked).

So far I have identified one wheel as an Alcoa 16” but the rest seem to be something else entirely.
I’ve replaced the leaky lights, cab lights, rear brakes, and it’s going to a local shop for the front brakes… cause hand tools can’t get them to come off.

663D829C-E55D-4457-B245-CB3B68BC0102.jpeg


Just bought a set of 255/85s for it, Yokohama MTs. The tire size is a real bear to find in stock.



D3E79208-98DD-48E4-99F9-A9CC3928E8B6.jpeg
 
trekking_LC said:
Specs are 454 with a touch over 200k, 4L80, currently unidentifiable tcase (aka haven’t looked).

So far I have identified one wheel as an Alcoa 16” but the rest seem to be something else entirely.
I’ve replaced the leaky lights, cab lights, rear brakes, and it’s going to a local shop for the front brakes… cause hand tools can’t get them to come off.

663D829C-E55D-4457-B245-CB3B68BC0102.jpeg


Just bought a set of 255/85s for it, Yokohama MTs. The tire size is a real bear to find in stock.



D3E79208-98DD-48E4-99F9-A9CC3928E8B6.jpeg
Click to expand...
You don't have an impact or breaker bar to do brakes?
 
Check the front frame over carefully. These things crack like a mofo when used heavy (service body, etc.)
 
total newb said:
Bw4407 is the tcase
Click to expand...
Ah, thanks, bw4407 or 4401 in my precursory reading I did read about both. Apparently very expensive to replace, preventive maintenance is the name of the game.

u2slow said:
Check the front frame over carefully. These things crack like a mofo when used heavy (service body, etc.)
Click to expand...
Yup, as soon as it’s back from the shop! I’ll be scrubbing the frame clean from the cab forward and then repainting it. Should give me some time to look for damage or cracks.
Since this was a service truck I’m sure it was offroaded a bit…

GBG8201 said:
I just did front brakes on my gmt400 k3500. Took a couple extractor sockets, oxy torch, and a big breaker bar.
Click to expand...
That’s what I was beginning to suspect. Unfortunately I’m in the middle of moving between two states so I have almost no access to my normal shop tools and all the work has to be done on the gravel to keep surfaces clean…
Normally I would have put my purse down and clicked on the torch, but on my back in the gravel sucks.
 
trekking_LC said:
Ah, thanks, bw4407 or 4401 in my precursory reading I did read about both. Apparently very expensive to replace, preventive maintenance is the name of the game.


Yup, as soon as it’s back from the shop! I’ll be scrubbing the frame clean from the cab forward and then repainting it. Should give me some time to look for damage or cracks.
Since this was a service truck I’m sure it was offroaded a bit…


That’s what I was beginning to suspect. Unfortunately I’m in the middle of moving between two states so I have almost no access to my normal shop tools and all the work has to be done on the gravel to keep surfaces clean…
Normally I would have put my purse down and clicked on the torch, but on my back in the gravel sucks.
Click to expand...


Man up?....
 
trekking_LC said:
Ah, thanks, bw4407 or 4401 in my precursory reading I did read about both. Apparently very expensive to replace,
Click to expand...

The BW4407 was used in Ford trucks. I don't think GM ever used it but I am by no means an expert.

The BW4401 is pretty easy to find used. They don't fail often and it's usually from being run dry due to a leaky seal. ~$250 is the going price around here. I still have a spare I bought and never used. Keep fluid in it and it should last.
 
lt1yj said:
The BW4407 was used in Ford trucks. I don't think GM ever used it but I am by no means an expert.

The BW4401 is pretty easy to find used. They don't fail often and it's usually from being run dry due to a leaky seal. ~$250 is the going price around here. I still have a spare I bought and never used. Keep fluid in it and it should last.
Click to expand...
Looks like the 4401 was used as well as the 4470, np241c was only in the k1500… probably.
Some reading I did on the GMFS forum indicates that Chevy/GM had an extremely diverse selection of tcases that they installed in their trucks.
When I have time Friday I’ll clean it up and get a definitive answer.
Ya know… like I should have done the first time instead of speculating.

Either way, long term plan is definitely d60 swap and probably a Cummins 12v. Or maybe an 8.1! That’d be a lot of fun, gotta admit I like being a bit different than all the diesel truck guys.
I’ve owned/modified quite a few cummins powered trucks and we have 3 of them as work trucks currently. Good stuff for sure.
 
trekking_LC said:
Looks like the 4401 was used as well as the 4470, np241c was only in the k1500… probably.
Click to expand...
The 241/243 shows up in 1500 and 2500 trucks. The BW is a 3500 exclusive. There's a 13xx and a couple 44xx. One variant uses an electromagnetic clutch/synchro something or other.

Do a year/model lookup at www.car-part.com and you'll see what tcases were offered.
 
u2slow said:
The 241/243 shows up in 1500 and 2500 trucks. The BW is a 3500 exclusive. There's a 13xx and a couple 44xx. One variant uses an electromagnetic clutch/synchro something or other.

Do a year/model lookup at www.car-part.com and you'll see what tcases were offered.
Click to expand...
This is helpful.
I’ve read about the electromagnetic cases. I think they came in the Vortec 454 trucks, 1995-98? I hope so at least. They seem sort of quirky from what I’ve read.
 
241 was used in all trucks, bw 4401 in some 3500. They also used the 700r4 in 3500s for awhile too, so they knew the TBI wasn't capable of breaking anything.

My 00 has the bw case. I assumed that since I can't find any parts, it must never need them :laughing:

250k of abuse and mine is still going strong. Was just under it replace u-joints today.
 
This thread sort of died, my apologies, the truck is currently sitting out behind the shop waiting for warmer weather.
Long story short, after pulling the motor to redo the oil pump and other maintenance, the truck would not stay reliable.
Dies at stop signs, has a heat soak(?) issue, probably a vacuum leak I can’t track down.
I’ll fix it, but it’s not on the top of my list, I have a 1997 K3500 that stepped in to fill the work truck need. I must say, night and day difference between the 94’ and the 97’.
 

Attachments

  • BE7F7C48-CBFC-44AC-8F02-BAD179921DFA.jpeg
    BE7F7C48-CBFC-44AC-8F02-BAD179921DFA.jpeg
    2.2 MB · Views: 31
Have you replaced the crank position sensor? That can cause issues like dying at stops, misfires, and other issues that look like something else at first. I've been chasing a bunch of reliability issues with my 98 and that's the next step for me.
 
boy&hisdogs said:
Have you replaced the crank position sensor? That can cause issues like dying at stops, misfires, and other issues that look like something else at first. I've been chasing a bunch of reliability issues with my 98 and that's the next step for me.
Click to expand...
'94 didn't have a crank position sensor. That was introduced with the GenVI motors in '96.
 
Fuel pump? In my experience they only last about 100k. Might not be the only thing but depending on how old yours is it might be about that time anyway.

Does it have vac boost brakes? Probably not as a 3500 but those boosters are leaky POS's and the parts store ones they get replaced with are worse.

Edit: Everything I know is for the 96-98 engines but it's worth looking at.
 
Knock sensor and coolant temp sensor were common issues when it came to the TBI engines running like crap.
 
Distributor is out of phase maybe? Im assuming everything got taken apart and re sealed? Would check fuel pressure and vacuum leaks/ misplaced vacuum lines
 
You must log in or register to reply here.
Top Back Refresh