1991 454ss Rear End swap on my 1991 Silverado

[ObsKev]

Bought a 454ss 14 Bolt SF 5 lug rear end. Gonna swap it on my 1991 C1500 Silverado 10 bolt. Any fitment issues I’ll run into with swapping the rear end? Connecting the driveshaft back? (Running an all 4 inch aluminum driveshaft) Anyone know if the 454ss rear end has the 10 bolt yoke or the 14 bolt yoke?

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[FullBlowncustoms]

IDK, but I love it!! Friend of mine who lives behind me had a real nice one. I should have bought it.

 

[Schurkey]

When I put a K2500 rear axle into my '88 K1500, I needed a Precision 447 conversion U-joint (or equivalent.)

No idea if yours will need the same size or not. It'll be a different number, because aluminum driveshafts have to use "coated" U-joint caps to reduce corrosion between the steel U-joint caps and the aluminum ears on the driveshaft.

The U-joint I needed on my '97 K2500 was a 331C, with the "C" meaning "coated for use with aluminum driveshafts". You may--or may not--need the same U-joint.

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[ObsKev]

When I put a K2500 rear axle into my '88 K1500, I needed a Precision 447 conversion U-joint (or equivalent.)

No idea if yours will need the same size or not. It'll be a different number, because aluminum driveshafts have to use "coated" U-joint caps to reduce corrosion between the steel U-joint caps and the aluminum ears on the driveshaft.

The U-joint I needed on my '97 K2500 was a 331C, with the "C" meaning "coated for use with aluminum driveshafts". You may--or may not--need the same U-joint.

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Thanks for the response and information. Yours is a 6 lug right? When you tried connecting the old Ujoint was it too loose? My driveshaft guy said if it fits nice and snug I should be fine. Either way can find these u joints i need in an auto store or would I have to order a special one?

 

[Schurkey]

My '88 that got the axle swapped is a 6-lug. My '97 that has an aluminum shaft did not get the axle swapped, but I did put a Truetrac differential in it. No change to the yoke--which was a long story I wrote-up last year.

The U-joint size you need "should" be shelf-stock in any auto-parts store...except that you'll need the coated kind which might be special-order, available from the regional warehouse in a day or two.

I have no idea what size U-joint you have on that driveshaft, or what size the new axle takes. Maybe it's the same as what you have now. That'd be nice.

 

[Schurkey]

If you change the yoke on your differential, you'll have to re-set the pinion bearing preload. Not a job for a beginner. Not fun for anyone. The proper method would be to remove the axle shafts and then the differential, so that pinion bearing rotational torque can be measured. Then the differential bearings need to be preloaded, which on the 9.5" axle is done with shims on the left (to adjust backlash) and a threaded adjuster on the right for preload. So you'd re-use the same shim pack as it has now, and probably mark the threaded adjuster so it can go back exactly as it is--or close, if you choose to change the preload.

 

[someotherguy]

Something tells me the "hybrid" nature of the 454SS 14 bolt / 5 lug rear means it stands a pretty good chance the pinion yoke takes the regular ol' u-joint a C1500 truck would take. I could be wrong. Notice the little brakes compared to a 7200lb gvwr C2500 14 bolt. A similar 14 bolt is used in the RWD optioned Silverado SS GMT800's - yes they have a 9.5" 14 bolt SF, but they have small brakes like a 1500 truck.

Richard