Another ‘65 C20 14-bolt conversion

[Captainfab]

Nice writeup

The 4.10's with the NV4500 should make for nice highway cruising. What size rear tires are you running? I'm curious as to what your rpms are at 65-70 mph.

[duallyjams]

Originally Posted by captainfab

nice writeup

The 4.10's with the nv4500 should make for nice highway cruising. What size rear tires are you running? I'm curious as to what your rpms are at 65-70 mph.

x 2

[Shaky]

Excellent write-up and photos. It really goes to show: there's a lot of information on the internet, but not all of it is good! Nice job tracking down the right bearing preload procedure...

[azdeltawye]

Originally Posted by Shaky

Excellent write-up and photos. It really goes to show: there's a lot of information on the internet, but not all of it is good! Nice job tracking down the right bearing preload procedure...

Thanks – yeah I became much more aware of taper bearing preload after my pinion bearing mistake. 50 ft-lbs just seemed way too tight…

[azdeltawye]

Forgot the section about the pinion seal:

The pinion seal on the 98 and up AAM axle is a two piece deal; the outer seal which goes into the diff housing and the inner seal or yoke sleeve which is pressed on the yoke. All aftermarket vendors (Napa, Autozone, Rock Auto, etc…) did not have a listing for the inner seal. Curious, I went to the stealership only to learn that this inner seal is not available by itself; it can only be purchased with a new yoke for $175.00! I laughed out loud and left. After a little research on the web I found a complete seal kit with both seals, crush sleeve, nut and washer for $39.09 from Ft Wayne Clutch: PN 74020011.



Pinion bearing housing with outer seal, pinion with new crush sleeve and yoke with inner seal

Replacing the pinion seal required more work/skill than I had initially thought. I was planning just replacing the seal and re using the original crush sleeve. Unfortunately I went a bit overboard on torqueing the pinion nut upon reassembly which resulted in too much preload on the pinion bearings (~30 in-lb). So I had to get a new crush sleeve and try again… The second attempt was much better at 7.5 in-lb of preload. Fortunately the 14b axle has a removable pinion bearing housing which makes this job easier.


Measuring pinion bearing preload torque with beam-type torque wrench

[azdeltawye]

Giving the ‘new’ 14-bolt a workout with 3500 lb of river rock…

[Captainfab]

Nice.... No doubt making use of those overload springs
That's the kind of work these trucks were built for.

Originally Posted by azdeltawye

Giving the ‘new’ 14-bolt a workout with 3500 lb of river rock…

[azdeltawye]

Originally Posted by Captainfab

Nice writeup

The 4.10's with the NV4500 should make for nice highway cruising. What size rear tires are you running? I'm curious as to what your rpms are at 65-70 mph.

Thanks!
And also thanks for providing the excellent spring perches - much cleaner than trying to re-use the originals.

Tires are 235/85R16s which are about 31.8” in diameter. 70 mph is about 2200 rpm in 5th – see graph below. Each green line represents the RPM to MPH relationship for each forward gear.