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CK5
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1989 Crew Cab Tow Rig Build
- Thread starter Kay86K5
- Start date
So, what my plans are for this truck is first off, get it back to CO. I want this to be a really clean, dependable, nice tow rig. I am by no means making this into a show truck (that's not my style). I believe you either make a show rig/car, or you plan to use them. This thing is going to get used. I want to purchase a cab-over in-bed camper to put on this thing along with towing my K5 and go camping/wheeling with my family a lot.
So I am first going to fresh'n up the interior. Clean the carpet or replace it, figure out the headliner situation, fix the dash, get some nice new seat covers...and overall just make it a very nice rig to ride in. As far as exterior, as you can tell it is really, really clean. I just want to paint it a straight blue (no two tone) with a couple coats of clear on it. Does not need to be perfect, but I would like for it to look real nice from 10-15 ft away. I may throw a small lift on it (2" or so) or maybe just leave the stance as it is and throw just a little bit bigger tire on it, remember this is going to be a tow rig.
Then, as far as drivetrain goes, I want to just fresh'n up the axles, change seals and bearings/kingpin bushings and so forth. And as far as motor, that TBI 350 ain't gonna do it. So I plan to swap in a L18 8.1 liter motor into it. I thought about a 6bt swap, but I really want to keep this thing a gas motor and keep it GM. Plus, the more research I do about the 8.1 the more I freaking love that motor. I know with a good tune I could get close to 400hp and 500 ft lbs which is plenty that I want/need for what I am gonna do. I have not 100% decided on a tranny swap yet. Having either a 4l80e or Allison overdrive would be really nice, but the TH400 shifts really good in it right now. Still a little torn on it. If anyone has some real-world advice on this, please chime in!
Like I said, I just purchased this rig and don't plan on any crazy mods at the moment. I need to either find the motor or a donor vehicle before the motor swap will happen, so first on the list is making it pretty. Anywho....that's what I got, let me know what you think!
So I am first going to fresh'n up the interior. Clean the carpet or replace it, figure out the headliner situation, fix the dash, get some nice new seat covers...and overall just make it a very nice rig to ride in. As far as exterior, as you can tell it is really, really clean. I just want to paint it a straight blue (no two tone) with a couple coats of clear on it. Does not need to be perfect, but I would like for it to look real nice from 10-15 ft away. I may throw a small lift on it (2" or so) or maybe just leave the stance as it is and throw just a little bit bigger tire on it, remember this is going to be a tow rig.
Then, as far as drivetrain goes, I want to just fresh'n up the axles, change seals and bearings/kingpin bushings and so forth. And as far as motor, that TBI 350 ain't gonna do it. So I plan to swap in a L18 8.1 liter motor into it. I thought about a 6bt swap, but I really want to keep this thing a gas motor and keep it GM. Plus, the more research I do about the 8.1 the more I freaking love that motor. I know with a good tune I could get close to 400hp and 500 ft lbs which is plenty that I want/need for what I am gonna do. I have not 100% decided on a tranny swap yet. Having either a 4l80e or Allison overdrive would be really nice, but the TH400 shifts really good in it right now. Still a little torn on it. If anyone has some real-world advice on this, please chime in!
Like I said, I just purchased this rig and don't plan on any crazy mods at the moment. I need to either find the motor or a donor vehicle before the motor swap will happen, so first on the list is making it pretty. Anywho....that's what I got, let me know what you think!
Congrats man! I know you've been talking about this for a bit. You have got to be pretty happy with a rust free find like that!
I also have the same plan for the in-bed camper.
I also have the same plan for the in-bed camper.
Also, that Allison trans is my favorite trans ever. I love the way it shifted, and I loved how it towed.
ThatK30guy has my old truck now, and can vouch that those 8.1/Allison combo's are stout m'fers.
ThatK30guy has my old truck now, and can vouch that those 8.1/Allison combo's are stout m'fers.
Thanks bud, yeah I was going back and forth with it for a while. Kept looking at the old crew cabs, then back to the new trucks. But overall I decided to go this route cause 1) it is just so much cooler of a tow rig
and 2) I know I can build a tow rig for less than just buying a "newer" used one with almost 300,000 miles on it. It should be really fun to build this thing. I plan to continue to use my current truck (referenced above) while I build this one.
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Yeah, it is the most logical for what I will be using the truck for to get the Allison too, but from my research I believe the Allison does not fit inside the tunnel of these old square bodies, which would mean having to cut up the floor to make it fit. It's dooable, but trying to decide which direction I really want to go with. Everything will depend on the deal I find on either just a motor with complete harness and computer, or if I find a really good deal on a wrecked donor truck with the tranny there to steal....we will see
Fuggin sweet 
In regards to the transmission, I think it really depends if you want to be able to cruise at 75 mph? Then something with OD is going to be necessary. Or have you thought about a gear vendors OD unit?
In regards to the transmission, I think it really depends if you want to be able to cruise at 75 mph? Then something with OD is going to be necessary. Or have you thought about a gear vendors OD unit?
Couple other random pics....I freaking love these GMC year/style of grills!!!!
Nice truck. I have seen the same problems with overpriced crew cab trucks in my area. Will be watching to see how this transforms.
Oh, I forgot to add in it's current state right now, the motor is not running worth a crap. My brother said it has a hard time starting (takes a while cranking before it will finally fire), once it is running it will idle just fine but once you try to give it some gas it has a horrible hesitation. He is thinking it may be the intermediate hose on the fuel pump (hose that connects the pump to the fuel line). I may try and at least get it running ok to allow the truck to be mobile while I search for a motor, cause I am not sure how long it is going to take me to find the right deal on that. So we will see.
But once he had it running he said the TH400 was shifting just fine. It had the feeling like someone installed a shift kit in it as the shifts were a little deeper and firmer than stock. The NP205 shifts good (as normal as most all 205's shift) and there are no unusual sounds or feelings from the d60 while in 4wd or anything that hints of death wobble. Steering column feels nice and tight though steering feels sluggish. This could be due to a power steering pump going out, or the fact that the front tires are at pretty low PSI, or both. Either way, the motor issue doesn't really bother me since I plan to swap an 8.1 liter...maybe it will just get me to getting on the swap earlier rather than later
FYI, for anyone reading this if you have a lead on a good 8.1, feel free to let me know, haha
But once he had it running he said the TH400 was shifting just fine. It had the feeling like someone installed a shift kit in it as the shifts were a little deeper and firmer than stock. The NP205 shifts good (as normal as most all 205's shift) and there are no unusual sounds or feelings from the d60 while in 4wd or anything that hints of death wobble. Steering column feels nice and tight though steering feels sluggish. This could be due to a power steering pump going out, or the fact that the front tires are at pretty low PSI, or both. Either way, the motor issue doesn't really bother me since I plan to swap an 8.1 liter...maybe it will just get me to getting on the swap earlier rather than later
FYI, for anyone reading this if you have a lead on a good 8.1, feel free to let me know, haha
Fuggin sweet
In regards to the transmission, I think it really depends if you want to be able to cruise at 75 mph? Then something with OD is going to be necessary. Or have you thought about a gear vendors OD unit?
Well, this truck will by no means be a DD. It will basically pull duty of what my current truck does which is sit outside my house and get used every couple of weeks to haul stuff. Every once in a while it will see highway speeds without towing (such as going to ride dirt bikes or pheasant hunting, things like that) where it would be very beneficial to have OD.
I am not sure if the gear vendors would really be worth it with the price tag they have on those things. I bet I could swap in a 4l80e for cheaper than that. But the 4l80e, at least in my opinion, doesn't have that great of gear options. 1st isn't low enough, and there is too much of a gap between 2nd and 3rd. That's why I think the Allison is the best option, but there is more fab work to get it in there (cutting floor/rebuilding it back up, crossmembers, figuring out the shifter, ect).
But then I thought maybe I just work on getting the motor in bolted to the Th400 and run it like that for a while, then when time/money allows, do a OD tranny swap...
So many things to consider, haha
No doubt the allison would be ideal if you can fit it. I've seen the gear vendors go for under a $1K used on CL, just an idea.
Then again if you come up on a 8.1L/4l80e combo that's priced right, I'd go that route.
Then again if you come up on a 8.1L/4l80e combo that's priced right, I'd go that route.
89 crew cabs seem to be really prevalent around CK5. Congrats on the purchase; didn't seem to take you long to find what you were looking for.
I've often thought for my crew I'd like to have the transmission that's in my '08 2500HD. It's 6 speed and has a true tow/haul mode. Not sure if it's a practical or even possible swap. Biggest thing that amazes me is how cool it runs even loaded.
Eventually I'm planning to put in an air bag assist in my crew sounds like it might be a good idea for you too with a slide-in camper in the mix.
I've often thought for my crew I'd like to have the transmission that's in my '08 2500HD. It's 6 speed and has a true tow/haul mode. Not sure if it's a practical or even possible swap. Biggest thing that amazes me is how cool it runs even loaded.
Eventually I'm planning to put in an air bag assist in my crew sounds like it might be a good idea for you too with a slide-in camper in the mix.
How much clearance do you need for an Alison? Would a 1" body lift give enough clearance?
Martin
Martin
89 crew cabs seem to be really prevalent around CK5. Congrats on the purchase; didn't seem to take you long to find what you were looking for.
I've often thought for my crew I'd like to have the transmission that's in my '08 2500HD. It's 6 speed and has a true tow/haul mode. Not sure if it's a practical or even possible swap. Biggest thing that amazes me is how cool it runs even loaded.
Eventually I'm planning to put in an air bag assist in my crew sounds like it might be a good idea for you too with a slide-in camper in the mix.
Do you know what tranny is in your 08 HD? Is it the Allison with the upgraded 6 speed, or is it an upgrade of the 4l80e?
Yeah, I thought it was gonna take me longer to find one I really wanted. At first I was gonna buy a 2wd one that wasn't even running, just a good body and hopefully find one for $1500, but as I looked even those types were going for $2000-$3000, especially here in CO. So when I found this one where most of the stuff I was gonna do was already done (other than fresh'n up and paint...and it was already 4wd) at a pretty good price, I had to jump on it. It sucks that it's in WA, but I guess that is just what you have to deal with sometimes.
I have thought about air bags for sure. I think what I am gonna do is put a small lift and a littel bigger tires on it first and tow like that for a while. Since I don't have a camper yet and won't get one until this truck is really rocking, I will hold off on that. But if you end up doing it maybe I could come up and help you install so I can see how everything goes??
You raise a good point. I have just started my research on the Allison swap and have found a few guys who have said there is not enough room under there to fit it, but no body lift has been talked about. If a 1" body lift would give me the clearance to fit it, then it would be a no brainer. I would do a 1" body, 2" suspension, maybe some 315x75x16 (or 17's) with the 8.1 and Allison with a 205 behind it......man it gives me goosebumps just thinking about that setup, haha
If anyone has some experience with Allison swaps on these things, please chime in.
A set of Timbren's is on my list for upgrades. Since I will be in the same boat with an in-bed camper and and pulling my K5. The bags, if aired up separately of each other, will also act as a rear swaybar as well as keep the load level. I think a set only runs about $150.
Edit: I stand corrected. They had a sale going on for $150. They are usually $250ish.
Edit: I stand corrected. They had a sale going on for $150. They are usually $250ish.
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6L90. From what I understand, 2008 was the first year they went away from the 4l80e in the gas trucks. Mine is a 6.0L.
