need help as I'm replacing the leaking input shaft seal in a np233 transfer case on a 95 blazer. I read that the retaining collar needs to be removed to replace the seal, but I can't get the collar's bolts to budge. they're 5mm allen head bolts. can I replace the seal without removing the retaining collar?

 

I see no way to get the old seal out without removing the metal surrounding the seal

Use one of these with a socket/allen wrench.
https://www.acklandsgrainger.com/AGI...150818162706:s

Or have someone rap on the head of the bolt with a punch/hammer while you put pressure to turn it - or even turn them with the punch at an angle as a last resort. Note this might ruin the screws but you can find them. The shock of jarring is what works to break it loose either way.

 

I used a impact screwdriver that you hit with a hammer and they won't move!

 

Sorry but if you can't get them out using the methods I described, then take to a machinist or someone with the tools and experience. Transfer cases are expensive. Might be worth it to have someone remove those screws for you.

 

The seal comes right out of that plate from the outside with a suitable seal puller or a pry bar and a screw. No need to go through the hassle of removing the input bearing retainer (a.k.a. "the plate")! Don't be gentle with it. All you need to worry about is not damaging the input shaft sealing surface or the stationary sealing surface that the outer shell of the lip seal mates against.

I have replaced this seal on a few different NP233/NP243 and the awd cases over the years and never have I pulled the input bearing retainer.

 

found out from a chevy mechanic at the dealership that the collar doesn't need to be removed! just pried out the old seal with screwdriver.

 

I stand corrected! Good job!

 

thanks guys!

 

Great info. Anyone know the seals part number? Thanks

 

I changed mine a couple weeks ago. Front seal Timken # TMS 3173


T-case to adapter gasket. Felpro # FEL 72769