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Author Topic: Crew Cab Conversion Information Wanted  (Read 291 times)


  • Single Axle Driver
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Crew Cab Conversion Information Wanted
« on: December 08, 2018, 03:14:03 PM »
Hey all,

So, I am the owner of a 2001 Chevy C3500HD, of the medium length variety (~159" wheelbase, if I remember correctly). I recently purchased a crew cab (just the cab) from a 2000 C3500, and am beginning to strip them down in preparation for putting the crew can onto the HD frame.

I found a PDF of the GM upfitter manual, so I have plenty of dimensions and specifications. I think I know what I'm in for as far as stretching the portion of the frame under the cabin, I'm probably going to have some lengths of channel fabbed up to spec and do all of the cutting and welding myself. Clearly, I'm also going to have to fabricate some new body mounts and alter the lengths of the driveshaft, brake lines, etc. Does anyone have any information about any other aspects of this process? Have any of you done this yourselves before?

I'm also interested in converting to four wheel drive in the future, most likely by trying to hunt down a 4x4 4L80e with a push-button transfer case, but I'm also open to the idea of a divorced case. What do I need to know and be prepared for as to the addition or alteration of crossmembers?

Thanks in advance for any info / help you can provide, this website is a treasure trove.


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Re: Crew Cab Conversion Information Wanted
« Reply #1 on: December 09, 2018, 07:22:55 AM »
I'm sure someone will jump in about the body mounting....there is a lot of info relating to 4X4 conversions in the Tech = Help area.


  • 3500HD Driver
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Re: Crew Cab Conversion Information Wanted
« Reply #2 on: December 09, 2018, 08:49:13 AM »
I’m not an expert when it comes to frame stretching so I’ll stick to the drivetrain portion of this. Do you have a drivetrain to start with? Which engine would you like to end up with? If you’re going the factory level route a 4l80e is ok, these trucks came with 4l85e’s, same thing but slightly different.
     Push button tcase for the 4l80e would be the np243c known to be pretty tough but not in the HD catagory, not to say it wouldn’t be up for the job. One problem with the 243c is some of the yoke sizes for u joints and the fact that it never had a park brake mounted to it which you would need for inspection. Custom park brake set up are available for some t cases.
     Getting a Dana 70 front which was purpose built for this truck is going to be hard to find. Buying an axle set from an f450 from the early 2000s will be easier to find, they will be Dana axles but you will need the rims to go with them, not sure if f450 rear axle has a park brake or if you would still need a tcase brake. Lots more to consider so any questions are welcome
1999 chevy HD 4x4 135.5" 6.5 nv4500 bw4470 Dana 70 HP 10 lug front

Due to recent budget cuts the light at the end of the tunnel has been turned off


  • Single Axle Driver
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Re: Crew Cab Conversion Information Wanted
« Reply #3 on: December 09, 2018, 05:24:44 PM »
Awesome, thank you for the information.  The HD is currently a running truck, with the 6.5L Detroit turbodiesel, automatic transmission, and the Dana 80 rear with 5.13 gears.  I intend to keep the 6.5, odometer says ~185k so it should have plenty of life left.  Eventually, I would like to regear the rear end to 4.30 or even 4.10, between the tall gearing and it being a diesel, the revs would be a lot higher than I'd really like at highway speed.



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