NP205 Speedo leak
 

Okay so I have searched this forum and others as well for some help. I am trying to fix a leaking speedometer cable coming out of my NP205 and understand that this sleeve P/N 326561 is the ticket. However, I did find that its the seal inside the sleeve that goes bad and that is whats causing the leak. I believe the seal is a 10mm x 16mm x 4mm seal like this one: https://www.fastenal.com/products/details/4190264

Id rather pay $3 instead of $30.


All the other threads addressing this issue are old and the links no longer exist to the correct part. I am looking for some confirmation before moving forward.

Re: NP205 Speedo leak
 

Just go to your local transmission shop and tell them what you need, they've probably got a couple dozen of them sitting around from the transmission kits left over. Get a couple of them, grease them up a bit and double them up

Re: NP205 Speedo leak
 

Yes that's the right size, I ordered mine from ultimate industrial when I resealed mine over a year ago. But I believe that link is gone also. Anyway it's still leak free.

Re: NP205 Speedo leak
 

I know this an old thread but did this fix the leak?

Re: NP205 Speedo leak
 

This might help; luckily I haven’t had to deal with this yet on mine.
http://67-72chevytrucks.com/vboard/s...d.php?t=804094

Re: NP205 Speedo leak
 

I went ahead and ordered the above Fastenal seal. I got two in case I jam one up. I don't want to alter the speedo output with a punch even though I have two transfer cases. I will keep you all posted and if it works well I will start a newer thread with the link to keep us all sealed up. There has to be thousands of 205s dripping somewhere on someones driveway.

Re: NP205 Speedo leak
 

i just replaced my speedo cable seal. only one seal that wil cause a leak out of speedo cable area. reach out to mark at motorcity k5. he has the seals in stock. there are two different sizes Attachment 2038392

Attachment 2038393

Attachment 2038394

Attachment 2038395

Attachment 2038396

Re: NP205 Speedo leak
 

Alrighty. So I still don't have the right seals. BOO! The fastenal seal fits the speedo shaft but does not fit the hex bolt in section thingy. AGH! I have 2 205s and both are the same.

Re: NP205 Speedo leak
 

there are two sizes of seals. .635 outer diameter and .500 . measure the inner diameter of the part that threads into the np205.

Re: NP205 Speedo leak
 

And all these years I thought they were SUPPOSED to leak.

FtP

Re: NP205 Speedo leak
 

Oh shiz. I must have the smaller seal. Both my 205's are the same. One is a 72 and not sure on the other but it had a slip rear shaft and has a 4x4 indicator switch on top. The speedo drive is the same configuration though. The fastenal seal fits the drive just not the hex housing. It seems kinda tight on the shaft but fits. Should I just look for a new housing and what year would that be?

Re: NP205 Speedo leak
 

Alrighty. I am ready to go after this leak again. I have the two seal that did not work for me. Does anyone want them? I could probably get away with an envelope and a stamp for the shipping. My treat. I just have to find them but I think they are on the seat of my truck.

Re: NP205 Speedo leak
 

Sorry to bring this back from the dead. Fighting the same issue as shown. Quick question.... Is there supposed to be any type of seal between the metal sleeve and the transfer case? It seems like just metal to metal, and that it would leak consistently there. O ring, flat gasket, or RTV?
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Re: NP205 Speedo leak
 

Go ahead and us sealant. I use Permatex 82180 Ultra Black Maximum Oil Resistance for this application. However, I would use what I had. Pipe sealant would also work.
I don't believe GM used a gasket, and the surface would be very small if they did.
The speedometers on the 205's were built before GM put a serious effort into oil leaks.
The early sleeve nuts didn't even had a seal installed in them. Look carefully for wear on the gear seal surface and for excessive play of the gear in the nut bore.