donor vehicle swapping

[res0wc18]

hello all i have a chance to pretty much recieve for next to nothing an 85 k20 4x4 diesel with the 14bsf and np208 auto hubs and 700r4. this has been a very well maintained truck one owner, my grandfather. I was considering swapping in the 700r4 and the 8 lug front and rear axles from the truck to my m1009 and was wondering how strong the 8 lug 10 bolts & 14bsf are and what axle gear ratios came in those trucks in those years. Also what problems am i going to run into doing the swap?

 

[acetomatoco]

Better to make a M1008 out of the K20.... Nothing will match up with the K5 (M1009) other than the Engine, Tranny etc.

 

[CUCVFAN]

The front 10-bolt is the same as the M1009, except the wheel hub/rotor. It is no stronger than the M1009. The 14bsf rears are stout, but will probably need to have the perches re-welded or shimmed to get the pinion angle reasonable in a short chassis like the K5. I think Four Wheeler magazine did the 14bsf swap into a Blazer as a project a few years back.

The other problem you will have is brakes. The proportioning valve will need to be changed or an adjustable one added as the wheel cylinders are larger in the 14-bolt and require more fluid. The front calipers are pretty much the same and can be maintained from the stock setup. You could always pull the entire brake system off the K-20 (prop valve and all) and see how it feels in the M1009. There's not that much curb weight difference, so it would probably behave just fine.

 

[AJMBLAZER]

Again, www.ColoradoK5.com .

Nothing will match up? It's a GM for chrissake, 90% of the stuff you need for the swap can be gotten with a GM part number! Ace, where do you get this stuff?

The spring pads and shocks are in their correct position on the rear axle. You'll just need the proper size u-bolts and either a conversion u-joint for the rear (one side fits 10 bolt sized driveshafts, the other fits 14SF sized yokes), or while they are shortening your driveshaft...which I beleive you will need to have done in the rear because the axle is bigger...you will need to have the yoke on the driveshaft changed to the size of the 14SF. I've heard of it being done both ways but the purely 14SF u-joint is obviously bigger and stronger.

Axle ratios should be something like 3.73 or 4.10 but you never know...GM was trying for the better mpg back then so every now and then they snuck in highway gears...

You sure that's a 700R4?

 

[CCATLETT1984]

It very well could be the 700r4, they put them in the suburbans, or someone might have swapped it in during its life.

 

[mangus580]

The 700R4 was the 'primary auto tranny' behind the 6.2 in the civvy world....

 

[BKinzey]

I'll agree with AMJBlazer. It shouldn't be that hard at all. The 700 coming from a diesel will already be set up for you as the Torque Converter and Govenor are different for a diesel.

Of course I think it's a good idea because it's what I'm doing although I'm putting in a 14BFF and a 6.5 Turbo in my M1009

 

[CCATLETT1984]

BK, when do you expect to have your 6.5TD together and in the vehicle

 

[res0wc18]

yes it is 100% sure that its a 700r4. So do you think other than re welding the spring perches on the back and the drive shaft issue its a bolt in job? Will there be an real headaches? will i need to grab the governer and vaccum stuff off the civy truck to make it work correctly?

 

[AJMBLAZER]

You shouldn't need to do anything with the spring perches or shock mounts. They should already be in the correct position. They only changed on the 1 tons and the HIGH GVWR 3/4 tons. If it was a high GVWR 3/4 ton it would have a 14FF.

 

[res0wc18]

so the axles should just bolt right in? What about the tranny?

 

[AJMBLAZER]

The tranny won't bolt right in unless you have all the parts to do it. Just about all of it can be done using GM or over the counter parts but it won't bolt right in the place of your TH400.