Detroit Diesel Build

FellowTraveler

Explorer
Your build plans

This is my first post. Just thought I would introduce myself. I've searched around here a bit as a visitor and finally purchased a vehicle I deem worthy of expedition travel. A 1998 GMC K1500 6.5L Diesel. Although these engine have had there issues with a few simple upgrades they can be great, long lasting and simple to maintain/work on. Its going to be a slow build, like everyone else, but it should be a lot of fun. Im starting with addressing the reliability of the engine and fixing up the little details of the truck then a full on build.

Short term plans include:
Larger diameter exhaust and downpipe
PMD relocation
New Injectors
Leveling Kit with Bilsteins
Tires and Wheels

Long term plans:
Solid axle swap with dana 44's front and rear
Front winch bumper
Rear bumper
Sliders
Bed cage and rtt

Ill try to post details and pictures along the way. Im really excited about starting this truck. The goal is to keep fuel mileage as high as possible and total height to a minimum. Even with the sas I would only like to fit 33's and I am willing to trim. Please feel free to comment or give suggestions. I would love the input.

-Tyler

A SAS conversion is not needed if you do that way it should be a hi-pinion ford frt diff d/s drop. However, you would be better served by going to the 1 ton IFS diff found in the K2500 and K3500.

Running 50psi to meet oem specs will batter suspension suggest poly susp bushings.

Cranking front torsen bar to lift is a bad idea, some aftermarket suspension manuf have a frt/ifs diff drop option.

As for 33.3" 255/85/16e on stock wheel would fit just right w/o mods and not stress anything suspension/bearing wise. Tire dia or gearset change requires vssb to be hacked to maintain speedo/trans shift calibration.

32.7" 285/75/16e will work on stock type rim of proper width and bs but bumper and rear of fenderwell my need some trimming.

35" will fit with cutout Bushwacker flairs, no lift needed, but offset and rim width would
stress your 1/2 sealed hub bearings and suspension for sure.

What transmission and gear ratios you have?
 
Last edited:

Greggk

ZombieSoldier
i love that bodystyle with the 6.5L. Almost bought one about a decade ago, but alas when i was looking the vehicle over and popped the radiator cap there was no coolant so I ran away as quickly as possible!
 

ExpoFeast

New member
A SAS conversion is not needed if you do that way it should be a hi-pinion ford frt diff d/s drop. However, you would be better served by going to the 1 ton IFS diff found in the K2500 and K3500.

Running 50psi to meet oem specs will batter suspension suggest poly susp bushings.

Cranking front torsen bar to lift is a bad idea, some aftermarket suspension manuf have a frt/ifs diff drop option.

As for 33.3" 255/85/16e on stock wheel would fit just right w/o mods and not stress anything suspension/bearing wise. Tire dia or gearset change requires vssb to be hacked to maintain speedo/trans shift calibration.

32.7" 285/75/16e will work on stock type rim of proper width and bs but bumper and rear of fenderwell my need some trimming.

35" will fit with cutout Bushwacker flairs, no lift needed, but offset and rim width would
stress your 1/2 sealed hub bearings and suspension for sure.

What transmission and gear ratios you have?

Im pretty set on the sas, Im not a fan of the torsion bar ifs for alot of reasons including cv failures, unit hub bearings and torsion bars. Your dead on about the ford dana 44. In fact Ive already got a line on a good hp out of a 1/2 ton.

Im not sure what you mean by running 50 psi wearing out bushings and such. The factory psi for this truck is 45 all around. Im running 50 just to keep it simple. Im planing on taking tread temps here soon however to determine the perfect pressure.

You are correct, skyjacker and rough country both offer 2-3" suspension kits for the front of my truck. However the tires I just put on fit with no rubbing so Im not as worried about the leveling kit. The measure out to 32.06," perfect for now.

I have the 4l80e and 3.73 gears.
 

FellowTraveler

Explorer
Your?

"Im not sure what you mean by running 50 psi wearing out bushings and such. The factory psi for this truck is 45 all around. Im running 50 just to keep it simple. Im planing on taking tread temps here soon however to determine the perfect pressure".

Reply: I was thinking the increased shock loads to suspension/steering associated with running tire at max pressure on bushings if they have not been replaced yet.

I'm guessing because you have a factory 6.5 (heavy) your front torson bars are higher rated to 3/4 ton which would add to the stress of running tire pressure over suggested oem spec.

I would think your oem 45 psi is with a loaded vehicle but could be wrong.

While not a K1500 my K2500 has two (2) stickers for tire pressure,
1 w/suggested psi @ max load 45 psi frt & 80 psi rear on (E) load range tires, other sticker shows lower psi for unloaded vehicle.
 

ExpoFeast

New member
I really appreciate your comments as I am definently learning as I go. There is only one sticker for tire pressure on my 1500. It recommends 45 psi f&r for a 245/75r16 load range c.
 

KLAKEBRONCO

Adventurer
Just a few comments or thoughts.
First, that is my favorite body style of all trucks. Not sure why, but I just like the styling, even over classic styles.

That truck is LONG. IMO that changes some things. First, the longer it is, the taller it needs to be to not get high centered and stuck constantly. Taller means bigger tires. Bigger tires mean bigger axles.

A really cool option would be to move the rear axle forward, lop off some of the frame, and shorten up the bed a bunch-which will require body work to not look butchered.


As for the rear axle......I use to feel the same way. I was going to keep the 8.8 in my Bronco (which I would rate ABOVE the D44 in strength)...I was even considering shaving it for even more clearance. I've since changed positions.
I can swap a ford 10.25 in, and not lose that much clearance. I will also never have to worry about it breaking. I figure that if a locker is in the back, that extra traction will just help me drag the diff over things. And when I'm not in a situation that requires that, I'll have the locker to help out all those other times too.

If you don't have the VSS in the axle, I would even consider the Ford 10.25 in that truck. You get near 14bolt full float strength and beef, but with MUCH better ground clearance.


One of the requirements for my Bronco is the ability to go anywhere by ourselves. Because of that I don't want things to break ever, and I don't want to get stuck constantly.
For an expedition/exploring vehicle I think those two things should be the driving focus of any project.
 

ExpoFeast

New member
KLAKEBRONCO, I definently agree with almost everything you've said, and if I was building a rock crawler I would head your advice. The toughest part of any type of project like this is deciding how far to go with it. I've owned 3 Jeeps that I spent alot of time and money on. The main goal I had during building was ground clearance. What I found out pretty quickly though was that after tires, axles, suspension, engine mods, etc. I put way to much money into these Jeeps and did not really gain all that much except headaches trying to make everything work together. This build will be focused on being able to get out of any situation I get myself into. However, Im not building a rock crawler, choosing to turn back or take a different line can be a much smarter (and cheaper) decision than building a huge truck. Cutting the bed depletes my storage space. Also moving the suspesion would require a shorter driveline and most likely create a steeper angle so on and so on. I may however flat bed the truck and chop maybe 6-12" off the total length or even just cut out the lower bed panels and build a high angle rear bumper. Also I plan to move the front axle forward a bit during the SAS. With the suspension I am trying to use off the shelf parts that I can get any where in north america if need be. I want a reliable simple truck. Thats my goal.
 

roostercruiser

Adventurer
I wouldn't go with a semi float. You can pick up full floaters all day long in junk yards for around $100. Most have 4.11 gears. You can get a matching set with Dana 44 front for around $200-300 total.full floaters are much stronger. I throughout my semi 14 . I couldn't give it away

cheers

Roland
 

Outback

Explorer
The Dana 44 axle will get you better fuel economy compared to the 14 bolt. The Dana 44 can be built almost as strong as a Dana 60. I will be putting Dana 44s on my wifes Suburban (as soon as I find one with barn doors and a 6.2 diesel).
 

bftank

Explorer
the rear dana 44 is going to be much skinnier than your stock 10 bolt rear. and you wont be gaining any strength.

do a ford hi pinion 44 front out of f250 so you get leaf spring mounts
and a ff or sf 14

i would do a ff 14 with a shave and a diff cover and call it a day.
 

dragogt

Adventurer
The Dana 44 axle will get you better fuel economy compared to the 14 bolt. The Dana 44 can be built almost as strong as a Dana 60. I will be putting Dana 44s on my wifes Suburban (as soon as I find one with barn doors and a 6.2 diesel).

For the price you'll pay to upgrade/ build the D44 you could buy D60 front and 14 bolt..

the rear dana 44 is going to be much skinnier than your stock 10 bolt rear. and you wont be gaining any strength.

do a ford hi pinion 44 front out of f250 so you get leaf spring mounts
and a ff or sf 14

i would do a ff 14 with a shave and a diff cover and call it a day.

This..
 

FellowTraveler

Explorer
KLAKEBRONCO, I definently agree with almost everything you've said, and if I was building a rock crawler I would head your advice. The toughest part of any type of project like this is deciding how far to go with it. I've owned 3 Jeeps that I spent alot of time and money on. The main goal I had during building was ground clearance. What I found out pretty quickly though was that after tires, axles, suspension, engine mods, etc. I put way to much money into these Jeeps and did not really gain all that much except headaches trying to make everything work together. This build will be focused on being able to get out of any situation I get myself into. However, Im not building a rock crawler, choosing to turn back or take a different line can be a much smarter (and cheaper) decision than building a huge truck. Cutting the bed depletes my storage space. Also moving the suspesion would require a shorter driveline and most likely create a steeper angle so on and so on. I may however flat bed the truck and chop maybe 6-12" off the total length or even just cut out the lower bed panels and build a high angle rear bumper. Also I plan to move the front axle forward a bit during the SAS. With the suspension I am trying to use off the shelf parts that I can get any where in north america if need be. I want a reliable simple truck. Thats my goal.

Moving the frt/diff forward some sounds like a good idea, and make sure the frt/diff you get does not have unit bearings for easy repair and service in the field.

If you can find an ole WARN "Classic" winch bumper you gain frt/ground clearance over stock bumper, then again there are bumper brackets that raise the bumper when going w/body lift. I would not recommend anything ober 2" w/body lift which on a diesel is much more time consuming because of having to make a modified rad/shroud.

That angle approach by removing part of the rear 1/4 is a great idea too so there is no loss in cargo area.

Remember, as you tweak your 6.5td you increase hp/tq and need to further protect motor/trans and have diffs that can holdup to the enhancements. I suggest a bypass oil filtration system like Amsoil sells but there are many bypass systems a big truck bone yards for much less $.
 

87GMCJimmy

Adventurer
the rear dana 44 is going to be much skinnier than your stock 10 bolt rear. and you wont be gaining any strength.

do a ford hi pinion 44 front out of f250 so you get leaf spring mounts
and a ff or sf 14

i would do a ff 14 with a shave and a diff cover and call it a day.



^this!!!
 

ExpoFeast

New member
So I finally installed my PMD relocation kit fron Pensacola Diesel. It was a really nice unit. It came with a new PMD, Heat Sink, Gasket, Extension Cable and Bolts. I made my own bracket to mount inside the stock bumper with some angle iron I had laying around. The whole install took about an hour, that included making the bracket and taking the grill off the truck.

I also got some hella 500's mounted on the front bumper. While the grill was off I ran the wires up to the firewall but I havent finished my switch and relay set up yet.

On a side note. I think I made my mind up on axles. The first front 44 I looked at out of a 1/2 ton was junk. So now I'm looking for a Ford HP Dana 44 out of a 3/4 ton. Im going to pair this with chevy 6 lug outers. Im going to keep my semi float 14 bolt for now. While I wear out these tires I am going to get all my parts sourced for the SAS.

Finally, I pickup up a used pro tech tool box. Craigslist special. Its in great shape and came with a key. Im going to mount it up tonight and hopefully get my hilift brakets installed too. Now for pictures.





 

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