1987 GMC V1500 Sierra Classic LS swap/build

[NastyBuzzard]

Anyone help with the QUESTION I have above? ^


One cool addition I made was installing a rear view mirror with the compass and temp gauge. Just got to mount it. I think it is neat anyways.



I also need help trying to hook up speedometer.

I worked on it forever last night.

The 2001 transfer case harness is on the left and the plug for the 241 VSS is on the right.



The harness has 2 male plugs that plug up under the hood near fuse box. I found one female plug for the harness right near fuse box but couldn't find the other to plug in. I grounded it and tapped the 91 vss wiring onto the 01 harness and couldn't get the speedometer to work at all.

I still need help on this. If I can do this I can take it for a trip to see how it does.

What I am doing is basically like if I was Solid Axle Swapping a 2001 Silverado with a GM Dana 44 and NP241 passenger side drop.

[Mtrhd329]

When i was working on my speedo i found that my 2001 pcm had two twisted wires coming in from the vss to feed the pcm and then a single wire out for the speedo. 4k ppm i think it was. I am using a 94 z28 cluster and it works great. You should be able to run your gauge directly off the speed output wire from the pcm if the pulses match. Not sure about how the transfer case needs to interface though im 2wd.

[NastyBuzzard]

Originally Posted by Mtrhd329

When i was working on my speedo i found that my 2001 pcm had two twisted wires coming in from the vss to feed the pcm and then a single wire out for the speedo. 4k ppm i think it was. I am using a 94 z28 cluster and it works great. You should be able to run your gauge directly off the speed output wire from the pcm if the pulses match. Not sure about how the transfer case needs to interface though im 2wd.

You are correct there is 2 twisted wires, there is actually two plugs at the end of the transfer case harness that share those exact 2 twisted wires. I tried to tie in the 91 VSS plug and got nothing.

Pulses do match it will interface fine just gotta get the wiring correct.

[NastyBuzzard]

Here are better pictures of the "transfer case harness."

This is the end that would go under the hood.



This end plugs onto the transfer case. The rear is for VSS and as you can see the wiring doesn't go back into the harness it just goes to another plug. From this and some help elsewhere I found out that there is supposed to be a jumper to connect this plug to the plug at the end of the transmission wiring harness. The other plug is for 4x4 indication.



So since for the life of me I couldn't remember where that jumper was or where in the world to find it, I did the next best thing, I cut the end off the pigtail at the end of the transmission harness and spliced in the 91 VSS and voila!! My speedometer worked!

Here is a video of me going through the gears, not sure if it is hitting 4th and going in OD though... Hard to tell, doesn't seem like it is. I say this because normally when I do this test with the rear wheels jacked up, once the TC locks up the speedometer shoots to like 80. I was having problems getting to 60.




So I got a little rambunctious. I started filling the radiator with water and was going to try and shoot down the dirt road.

After I finally thought I got it filled the first thing to go wrong was the top transmission line flew out the radiator and sprayed hot fluid everywhere. Apparently I forgot to put in the little locking clip.

From there I was worried that trans fluid & water got mixed because the fluid looked weird. Possibly from being hot, I am not sure. However, it doesn't appear they mixed.

So I plugged the line back up and tried to drive it around the yard. Then one of the lower hoses popped off and sprayed all my water out. The one hose I forgot to put the clamp on of course.

So I let it cool and checked to make sure no blown head gasket. Trans fluid and oil still clean.

I let it cool for a few hours and went back to fill it with water and then I couldn't get it to take any water at all, just kept getting hot and bubbling back.

So I finally just drove it into the shop at about 225 deg and shut it off. Fluids still look clean.

I guess the best thing to do is to jack up the front end and put in water to help bleed out air.

[y5mgisi]

That's awesome!

[NastyBuzzard]

Originally Posted by y5mgisi

That's awesome!

I hope I didn't let you down. She is getting close. I still say I want to be driving it every dang day this winter.

[Mtrhd329]

Thats cool you got it figured out! Usually two vss plugs are for a 4l80e trans. I guess the transfer case wants to get its speed input in there also! Getting closer now!

[NastyBuzzard]

Worked on the truck until about midnight again. I have about 1/2 of the wiring soldered and shrink wrapped!

I also put on the shocks. Does anyone know what size NUT IT TAKES FOR THE REAR BOLTS ON THE FRAME FOR THE SHOCK MOUNT? Apparently I lost those

I also drilled holes in the floor for my seats. I still need to do the holes for the console.

I am having problems with getting water in the engine and for it to cool like it is supposed to.

I think a temporary solution is to mount my electric fans and run them with a switch just to avoid any blown head gaskets or anything like that.

[NastyBuzzard]

The size of the nut for the rear shocks is 7/16."

Took it for a drive down the highway tonight. Got it up to 50 mph but didn't want to push it too bad. Shifts fine and torque converter locks up fine. She will run 60 at 1500 rpm. I also tested out the tow/haul button and it works fine.

It also was really neat when I got up above 15 mph or so my doors automatically lock, just like my 2004. For some reason though they don't unlock like my 04 when I put it in park, but that may be because I still have a few sensors unplugged.

It was definitely an exciting ride, got a new list of things to do but she is getting close!

[NastyBuzzard]

It is so nice to be able to just drive it out the shop and down to the house!



I still have a long ways to go but it is definitely nice motivation!

Also a neat little feature the truck has now is that when it gets over 20MPH the doors auto lock. However, they are supposed to unlock when you put the truck back in park. Mine doesn't. I have to figure out why or I may just remove that feature all together.

I didn't get to mess with it yesterday, it was our 2nd year anniversary. Plus it rained its ass off yesterday too.

Fingers crossed for being fully road ready before winter!

[MalibuSSwagon]

Did you use the Silverado tank and capless radiator? Or the stock square body radiator and overflow? I figured out from my swap, I used the stock square body overflow and radiator, that these engines will pretty much bleed themselves. I filled the radiator and the engine thru the upper hose. Then filled the tank and ran it. It'll just keep sucking water out of the tank until the system is full. I was getting air bubbling into the overflow for a few days. It was kind of funny because it would just be sitting in the garage and every once in a while i'd hear a bubble come out.

[NastyBuzzard]

I am using a 2006 34" wide radiator with the 2006 dual electric fans and the 01 reservoir.

In the beginning I was just filling the reservoir and letting it suck it in. Then I pulled the top hose off and was putting it in through there until it started coming out the top spout of the water pump. Then I put the hose back on and ran it.

I hooked the ds electric fan up to a temporary manual switch to cut on if it gets too warm. I THINK it is fine now and cooling properly but it does get a tad warm here and there so I have to switch on the fan. However it is still in the 90s here in the south.

[NastyBuzzard]

I got rid of about 95% of my exhaust leaks last night. All I had to do was actually tighten the bolts on passenger manifold, I literally only had them finger tight!

Also figured out the deal about the lock doors when I exceed 15 mph and that my donor truck was set to only unlock doors automatically when you pull out the key. So it all works, locks at 15mph and unlocks when I pull key. Even if I lock doors while I sit inside the truck and then pull key out they unlock. Nifty but I would still rather it unlock when I put it in park and lock when I exceed 15mph or when I go out of park.

Got to find out how to change it to that instead of with the key.

[MalibuSSwagon]

I would search the internet for that answer. It's possible that you can re-program that feature. My Dad's 2k Silverado is the same way, unlocks when you take out the key.

[NastyBuzzard]

Originally Posted by MalibuSSwagon

I would search the internet for that answer. It's possible that you can re-program that feature. My Dad's 2k Silverado is the same way, unlocks when you take out the key.

Yeah, I have searched. I have found several procedures for making it lock/unlock or making it do nothing. However, nothing specifically says how to make it unlock when put into park. I may not be reading it correctly though, I am not sure.

I know my 2004 Silverado has a different pcm and different bcm but still....

[Mtrhd329]

Im not familiar with this particular vehicle just thinking in basics here. Sounds like the bcm? Is looking for a signal from the key sensor wire maybe you can swap that input with a wire from the NSS or the indicator from the range switch on the trans to tell it to unlock vice the key sense wire. Just a thought.

[NastyBuzzard]

I swapped some old rims with some bald 31"s on them onto the back to try and bring up my rpms a tad, plus no point in bald 31s on the front and brand new 32s MT on the rear.



Here is a little drive video someone requested. I got on it a bit during this drive but didn't video it. I was insanely amazed with the extra power and it sounds soo good with the flowmasters even though I know they are probably the worst muffler for the LS.



My rpms around 45-50 are still real low even with 31s, I need to upgrade to 3.73s!

I am trying to find some 17" wheels that will fit my truck. I plan on probably 265/70/17 or some similar size tire. Possibly about a 2-3" lift.

[NastyBuzzard]

Just ordered some of these Vision (P# 84H7883NS) 17x8 Wheels with 4" backspacing and 108mm(4.25") center bore. They are only like $72 a piece from Summit/Ebay with free expedited shipping. If I would have known getting 17" wheels for a 73-87 4x4 where this cheap I would have done it loooong ago!



Some of my brake upgrade parts have come in as well.. Soon to be upgrading to 4piston calipers upfront on the Dana44



I didn't get much time to work on the truck over labor day weekend. I spent all my time stripping one of my parts cars to sell for money to get this truck finished. I really want to have it on the road by the end of this month.

[y5mgisi]

Sweet! Details on the 4 piston caliper upgrade?

[NastyBuzzard]

Originally Posted by y5mgisi

Sweet! Details on the 4 piston caliper upgrade?

I am pretty much copying this guy and what he did to his suburban.

http://coloradok5.com/forums/showthread.php?t=316597

I also am trying to find another 99-04 rear disc posi 3.73 rearend to swap under the truck.

[NastyBuzzard]

So here are the calipers. They are huge and heavy! About 11" long. I think they look great!



Here are the wheels, I love that 1 day summit shipping. 17x8, but the actual OD is about 18.5"



You can still see my fancy rotor and caliper through the wheel.



Another good thing is I got $20 summit bucks to put towards the other two wheels. I only ordered two for the front at this time. Not bad though for $72 a piece, in my opinion.

Now to get hub off and get the OD of it cut down to about 7" so it will fit in the hat of the H3 Hummer rotors, then a drill bit so I can install the newer style Silverado lug nuts, then I can mock it up!

[NorCalAnthony]

Man you are moving right along with that brake upgrade! I'm getting ready to start the same thing on my K5 so I'll definitely be watching to see how everything turns out.

Where did you get your calipers from? They look brand new lol. I got mine off CarPart.com from a low mileage H3 but they're cast iron instead of aluminum like everyone else seems to have... I may have to pick up a set of those wheels they look sweet and the price is hard to beat.

Were you going to try and keep the ABS from the newer truck? I saw your caliper brackets have the mounts for the wheel speed sensor (I ordered mine without them) and if you're going to swap in a newer real axle that may be another cool upgrade for your truck...

Keep up the good work

[NastyBuzzard]

I got mine from Amazon, they are about $100 a piece from there. No core charge and they are AC-Delco. I couldn't find a better deal anywhere. They are cast though just painted I guess. I thought they were supposed to be aluminum as well. No clue. I am thinking the aluminum were for the "special edition" H3 which isn't what we are supposed to use. I am not 100% sure though.

Thorpart only sells them now with the abs block welded on. If adding ABS wasn't such a pain in the ass, I would definitely do it. Considering I have all the wiring to control it, but plumbing in that ABS block from one of my donors would be way to much work right now. Maybe later I will come back and add it after I have the newer style rear as well.

Here is a little shot of the wheels on the truck, just wanted to see how they are going to look. I have to find some cheap used tires to get on there for now.



I am currently trying to find someone to modify my hubs by cutting the OD down to 7" so it will fit in the hat of the rotor as well as drill out the holes for the bigger wheel studs.

This 1988 (R25?) 2wd found its way to my house yesterday... Weird it has 3500 on the fenders though. 350TBI Th400 with 14bolt FF. Runs pretty good just has a bit of a water leak coming out from the rear of the DS head. Bare bones work truck though, but it is set up for AC.

[NorCalAnthony]

Originally Posted by NastyBuzzard

I got mine from Amazon, they are about $100 a piece from there. No core charge and they are AC-Delco. I couldn't find a better deal anywhere. They are cast though just painted I guess. I thought they were supposed to be aluminum as well. No clue. I am thinking the aluminum were for the "special edition" H3 which isn't what we are supposed to use. I am not 100% sure though.

Thorpart only sells them now with the abs block welded on. If adding ABS wasn't such a pain in the ass, I would definitely do it. Considering I have all the wiring to control it, but plumbing in that ABS block from one of my donors would be way to much work right now. Maybe later I will come back and add it after I have the newer style rear as well.

That's not too bad at all since my used ones ran me $90 with 30k miles on them. You wouldn't happen to know what size bolts came with your caliper brackets do you? ThorParts forgot to send them with my brackets...

I don't blame you at all for not wanting to ad the ABS system that just sounds like a whole new level of complicated. I was just curious since you've successfully transferred everything else from the newer truck lol.

[NastyBuzzard]

I checked online for the size. Seem to be M14 X 1.5 X 37.5.

I could add abs. I may add it. Not now though, problem is I keep adding things I want to do and not work to get it on the road.

After I add the rear end, adding ABS wouldn't be really difficult. There is this giant block that mounts under the truck in the 99+ that all brake lines and what not goes into that controls most of everything. I would have to make a mount for that then plumb it up. Too much hassle at the moment.

I really just want it on the road so I can drive the heck out of it!