• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

1998 k1500 hd with 6.5 into a 1989 k1500 4x4 350 gas

Husker6.5 said:
But is the 89's the 9.5" semi-floating 14 bolt (weaker) or the 10.5" full-floating 14 bolt (strongest) that can handle everything a 6.5 can dish out torque-wise? Just like the IFS differential, the lighter duty 8.5" or the 9.5" that still ran in front of the Duramax?
Click to expand...
89 should be a 28 spline 10 bolt rear axle, don't think they had the f44 rpo available in 89 for 1500's to have a 9.5" 14 bolt. You could get a C1500 from GM with the 6.5l and a 30 spline 10 bolt for a few years. As to the front, 6 lig is 8.25", 8 lug is 9.25".
 
So, if he's going to swap the 6.5 into his K1500 89, he'd best better swap in the 9.5" IFS differential (and CV shafts, spindles/hubs, control arms and torsion bars/mounts) and the rear axle from his donor truck, because his '89 K1500 has the much lighter duty 6-lug front and rear axle drivetrain under it?
 
Last edited:
Husker6.5 said:
So, if he's going to swap the 6.5 into his K1500 89, he'd best better swap in the 9.5" IFS differential (and CV shafts, spindles/hubs, control arms and torsion bars/mounts) and the rear axle from his donor truck, because his '89 K1500 has the much lighter duty 6-lug front and rear axle drivetrain under it?
Click to expand...
Definitely be the way I would run with it.
 
Basically removing the entire harness from the donor truck.
Then you remove the harness from the new truck. And install the donor one.

Where the harnesses go to the lights they might be identical- so examine those before removing because you might not need to use those. But everything engine, trans, dash, all needs to match the 6.5.

The other option is building your own harness. I’ve had that task enough to know is easier to remove a second harness and install than to remove the original then build the new one one wire at a time.
 
I also think that where the harness goes through the firewall for tje ECM/PCM, it would be a lot easier to use a grinder and a cutoff wheel and cut around the block connectors, then carve a similar hole, but a little smaller, through the firewall of the vehicle You will be using and just shove the harness through the hole and use some sheet metal screws to secure the sheetmetal with the connector attached to the vehicle You are fixing up.
 
Last edited:
Will L. said:
Basically removing the entire harness from the donor truck.
Then you remove the harness from the new truck. And install the donor one.

Where the harnesses go to the lights they might be identical- so examine those before removing because you might not need to use those. But everything engine, trans, dash, all needs to match the 6.5.

The other option is building your own harness. I’ve had that task enough to know is easier to remove a second harness and install than to remove the original then build the new one one wire at a time.
Click to expand...
Would i have to use the ecu still if i got mechanical injection, or if i wanted to keep the db4 can i run the ecu still if i keep the harness?
 
If you go mechanical injection you wouldn't need the computer for that side of the equation. However if keeping the 4L80 you will need a standalone transmission controller to get the transmission to shift properly. I know there's older transmissions that didn't require computers. And the 92-93 4L80 behind the 6.5 were mechanical injection and had their own TCM, so if you could score a 92-93 4L80 w/ TCM that would work. Or go to a manual transmission and be computer free 🤘

If keeping the DS4, you'll definitely need to keep the ECM.
 
Diesel amateur is correct.
But feeding info for all the dash gauges has to be dealt with also. As well and engine sensor differences.

Check with your local dmv that you can go from ds4 to db2. Many places require emissions standards stay met on 96 and newer which require the obd2 system in operation and ds4 to be with it. If they don’t care- then no sweat.

DB2 is my preferred choice. That why I bought the year hummer I did as well as the trucks I bought. I hate ds4. So my opinion is VERY biased. I would say yes to the db2.
But I suggest you get input from some of the pro-ds4 folks here before making a decision.
 
DieselAmateur said:
If you go mechanical injection you wouldn't need the computer for that side of the equation. However if keeping the 4L80 you will need a standalone transmission controller to get the transmission to shift properly. I know there's older transmissions that didn't require computers. And the 92-93 4L80 behind the 6.5 were mechanical injection and had their own TCM, so if you could score a 92-93 4L80 w/ TCM that would work. Or go to a manual transmission and be computer free 🤘

If keeping the DS4, you'll definitely need to keep the ECM.
Click to expand...
The 92-93 6.5l TCM will NOT work on a 94+ trans. I have posted about this numerous times, 91-93 4l80e's use a different epc solenoid and control strategy than 94+ 4l80e's use. This is why the db2 swap guide said to source a 94-95 6.5l van TCM, but they will not shift correctly in 4low unless you take the trans completely apart and add the 40 tooth output speed reluctor. Vans never had 4x4, so they cannot multiply the transfer case output speed sensor by the low range ratio to get the trans output shaft speed. Even many aftermarket controllers have this problem.
 
@THEFERMANATOR We're saying the same thing- I said he had to get a 92-93 4L80 w/ it's specific TCM or otherwise get a standalone controller for his existing 4L80 which is a 98 I believe. I've seen you post about this and was doing my best to relay your knowledge. Thank you for the tidbit about the van TCM and 4Lo, still managed to lean me something new 🙂
 
The guys on the hummer/hmmwv forum are running the TCI EZ-TCU
In combination with it for the 4wd is a Dakota Digital SGI-100BT

The last guy ‘Cander’ to try is and post success for his 1998 was just a couple days ago.
Eric did his with that in his hmmwv that was previously a th400 trans like years ago and has around 50,000 miles on it so far iirc. Eric had the Dakota digital one step older i think.
it is not a low dollar solution that everyone dreams of- but it works reliably and both companies have amazing tech support.
 
You must log in or register to reply here.
Back
Top