1984 K20 axle swap to 1988 V10 suburban

[MuddiGGEr25]

ok so i got the old axle and ebrake crap out of the way, i got the replacement spring pack installed on the pass side, but not the drivers yet, i checked and i will have to cut off about 1/2" of the center bolt so the plate will rest on top, also I had to remove 3 leaves including the master spring. i forgot the offset for the 56" version. It is well past quiet time here in the trailer court, so i am going to install the drivers side spring pack, roll the axle under and set the tires ready to go.

so tomorrow morning all that is left to do is:

1. Cut off excess centerbolt
2. mount axle to springs
3. attach shocks to axle
4. attach driveshaft (i opted for the $#*() joint to get me by for the time being)
5. attach brake lines (incl ebrake)
6. bleed brake lines
7. attach tires

if i am forgetting something obvious please please tell me because i am exhausted and will more than likely take off without something. I am going 275 miles each way, and 9000lbs behind me on the way back.

right now though the wife just got dropped off after work and brought me fuel so im thawing out lol

[hatzie]

I have tightened U bolts from Camaros, to Kenworths. I tight them with an impact gun. ( really tight ) I have never collapsed an axle tube.
As far as stacking up the 3/4 ton springs under the half ton main leaf. You said the current springs sag bad. This means the main leaf is worn. I would use the entire 3/4 ton pack, maybe slip one, or two of the 1/2 ton leaves into the pack if you want a little extra load capacity.

If the master leaf is worn then buy a pair from a spring shop.  They're pretty cheap.

I hope you're using torque stix...  I like bolts that could kill me or someone else to be evenly torqued to enough tension.

I collapsed a trailer axle tube when I was young and stupid.  A 30" breaker bar will put more umph on those bolts than most impact guns.  I've broken 5/8 u-bolts off... again when I was young and less careful.

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[MuddiGGEr25]

well sorry everyone for not getting on sooner, I am back from getting the RV had to get a room overnight bc we didnt arrive till about 10pm, took all of 5 minutes to load it up using a skid steer. i will be trying to unload it here in a few in my driveway, hope fully it just rolls off (controlled of course lol)

MY conversion U-joint was incorrect so i had to make do using the end caps from the one i removed to use in the driveshaft.

My airshocks were not in on time so i had to leave the old ones in, which hold 0psi because one is completely blown out, i probably would not be sagging so hard if those had come in on time.

I do not think the master leaf is worn, i think its just due to the fact that the front springs i am using are for the weight of a 6.2L w/ A/C and i have a 5.7L with no A/C or smog.

I tightened the original u bolts with the best 1/2 drive snap on impact we had available at the shop.

I will be adding either 2" or 4" block lift with new ujoints to help even it, but once i get the winch and bull bar on the front it will help too.

I hauled the trailer empty 275 miles at 50-60mph achieving a wholloping 8.5mpg

Once there I found out I was 2qts low on engine oil, 1qt low on ATF, and my Tcase was almost empty as well.

I loaded the RV up onto the trailer, it weighed 9,600 last time it was on a scale but that was with the PO belongings in it, empty it weighs around 7,500-8,500 would be my guess.

My hitch is "rated" 500 tongue WC, 5,000lbs trailer WC, 750 tongue WD, 7500lbs WD.

My ball is rated 10,500

Rental trailer rated at 14,400lbs GVWR, (2-7,200lb axles)

Trailer empty weight around 3,000lbs

I had NO brake controller so I was only utilizing the brakes on the suburban.

My max sustainable speed in 3rd gear on flat road with small breeze was 55MPH (my gauge said 65, but GPS said 55) 2500RPM

2nd gear would hold 55mph must better with less throttle, but my alternator bolt snapped off and i had to use a tie down strap to put tension on the alt for the remaining 400 miles, so i didnt want to rev it too high since the serp belt is crooked.

max speed in 2nd up a very steel hill , small breeze was 55mph 3600RPM

I am taking a gander and going to say since my power dropped off at 3600RPM up a steep hill, thats where my peak TQ is at. I will say it was by no means a speed demon, but i never got below 50mph either.

Trans was not overly hot when i grabbed the dipstick by hand after towing for 100 miles so it was staying fairly cool.

Engine did not go over 200F on the gauge (well the only reference is 210F but it stayed a good bit below that mark)

Oil gauge does not work.

here are some pics of it throughout the day.

any questions feel free to ask.

[hatzie]

Getting there.  Now you need to swap the right speedometer gears into the transfer case tail. 

You need tire size and axle ratio to calculate em.  Plug the tire and axle ratio into one of these spreadsheets...  xls is Excel 97-2000 format ods is open document spreadsheet for the free Libre Office spreadsheet applet.  They're the same sheet just some incompatible font and layout differences between office packages.
http://www.mediafire.com/download/zk4j8ymtctekx5r/RPM_Gear_Axle_Transmission_TransferCase.zip

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[MuddiGGEr25]

absolutely, but first i have to decide if i want to go with 31's 33's or 35's bc obviously that will affect which  speedo gear i will need lol. but i really like having the spunk of the 4.10 so i think i might stick with 31's (235/85r16 is pretty darn close) and ive got 4 load range E work horse tires already

[hatzie]

absolutely, but first i have to decide if i want to go with 31's 33's or 35's bc obviously that will affect which  speedo gear i will need lol. but i really like having the spunk of the 4.10 so i think i might stick with 31's (235/85r16 is pretty darn close) and ive got 4 load range E work horse tires already

235/85 16 is 31.7" so you're there.   I run 265/75 16 on my squares and my T400 with no issues.  Same height 31.6" and a little wider.

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[MuddiGGEr25]

Ill definitly be sticking with the 235's for a bit anyway, i paid $50 for the set of 4 with about 25% tread left, load range E and studdable, then $96 to get them mounted and balanced on the nice digital equipment. but if i can grab a set on 8 lug rims for under $250 im all game, ive seen a few but im usually about a day late, but i do know where i can get a set of 40X15.00R18 for $175 but then i need rims and mount and balance again -.- not to mention lift and trimming

[MuddiGGEr25]

Getting there.  Now you need to swap the right speedometer gears into the transfer case tail. 

You need tire size and axle ratio to calculate em.  Plug the tire and axle ratio into one of these spreadsheets...  xls is Excel 97-2000 format ods is open document spreadsheet for the free Libre Office spreadsheet applet.  They're the same sheet just some incompatible font and layout differences between office packages.
http://www.mediafire.com/download/zk4j8ymtctekx5r/RPM_Gear_Axle_Transmission_TransferCase.zip

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Was just looking into this, and from what ive been reading i need the black 40tooth gear to get my speedo reading correctly?

I am pretty sure my NP208 has the 15tooth drive gear, but dont feel like crawling under during a thunderstorm to check lol,  is this a simple swap? im getting tired of my speedo being 10MPH over at just about every speed lol and decided to stick to 235/85 or 265/75 for the time being and a set of 7.50-16LT with some 2-3" lugs for offroad so those would all be roughly the same size