NV4500 Rebuild Questions

[campfire]

Update

I have accumulated enough pieces that I decided to try a mock-up today. Took my (mechanical) bell housing out to the NV4500, removed the IFS-era bell housing, and found that my bell housing isn't even close to fitting. The center hole is significantly too small, and none of the bolt holes are even close. I also have a hydraulic bell housing, which appears to have the correct hole size, but the same (wrong) bolt geometry.

So.....what did I screw up this time? This is a far cry from "drill one hole and it will fit."

GMT-400 drive train disassembled:



Newer bell housing at top. Older one at bottom. On the old one, the offset bolt hole is the only one that's even in the ballpark. The others are all too close to center.



If I kept the bell housing spacing I'd have to tap bolt holes into the face of the transmission.



Back end. Looks tremendously cleaner inside than outside. Should I be worried about the grease/sludge that seems to be leaking out the bottom?



And one very dusty gearbox:

 

[82355]

What is that bottom bell housing from?

Martin

 

[campfire]

What is that bottom bell housing from?

Martin

Not sure what its original application was. It is #464697. Google is indicating sbc --> Chevy 4-speed, but not necessarily the SM465. Hydro bell housing is #15530202. Both appear to have the same bolt pattern, and that's what's messing me up. I'm not quite willing to drill and tap the face of the tranny at this point, but I'm not sure how else I'll be able to attach it.

 

[dyeager535]

The only one known to fit is the 85-91 R/V bellhousing, and that is the one that apparently requires just one hole being drilled. It's in the face of the trans, but it doesn't affect anything.

 

[campfire]

The only one known to fit is the 85-91 R/V bellhousing, and that is the one that apparently requires just one hole being drilled. It's in the face of the trans, but it doesn't affect anything.

Anybody know what part number that one is? I would have thought that my late-model hydraulic bell housing is what 85-91 trucks were using...

 

[POORBOYK5]

Anybody know what part number that one is? I would have thought that my late-model hydraulic bell housing is what 85-91 trucks were using...

correct. that bell is the 85-91 R/V bell. I wish I had realized what you were doing before hand. I could have mocked it up to one of the 7 NV4500's I have kicking around the shop. I've never heard of this bell being modified for use on a NV4500. Interested to see how this all turns out.

 

[campfire]

correct. that bell is the 85-91 R/V bell. I wish I had realized what you were doing before hand. I could have mocked it up to one of the 7 NV4500's I have kicking around the shop. I've never heard of this bell being modified for use on a NV4500. Interested to see how this all turns out.

Yeah. I should have asked a few more questions. But this thread had dragged on long enough that I thought I had collected enough advice. I guess not.

I wanted a challenging project, so I'm not too worried at this point. But I'm bummed that neither bell housing looks cooperative. My fear now is that I'll end up with a pile of non-fitting parts before I'm done...


So, to repeat the million-dollar-question...Why, if I do indeed have the recommended bell housing, is it not behaving like the folks here predicted?

I did hear the calls to drill and tap the transmission face, but that doesn't look very fun at this point.

 

[82355]

That is NOT a 1985-1986 C/K or 1987-1991 R/V hydraulic bellhousing. They have an integral slave cylinder mount on them.

Martin

 

[campfire]

That is NOT a 1985-1986 C/K or 1987-1991 R/V hydraulic bellhousing. They have an integral slave cylinder mount on them.

Martin

True. The bell housing we are referring to (casting #15530202) is not shown in the pictures. I have the mechanical bell housing, the hydro bell housing, and the GMT400-series bell housing that came with the tranny. And none of them look very useable at this point...

 

[campfire]

Picture of the two older-style bell housings side-by-side...



And I now have a 6.2 flywheel ready to roll. Plenty heavy compared to the sbc flywheels that I have dealt with...



But the bell housing still has me confused.

 

[kennyw]

Tale a pic of the Hydro Bell on the NV4500. One from the input side and two from the other side to show the bolt pattern alignment.

 

[campfire]

Sorry for delay. I took pictures and then neglected to post them. Here ya go:






This is what it looks like today:

 

[campfire]

Bump.

Do none of the folks recommending this bell housing adaptation have responses for what I did wrong? I obviously have messed something up here....

 

[kennyw]

Can you post a pic of the older style hydro bell placed on the front of the NV4500? I would like to see how far off the holes are.

 

[82355]

I haven't seen you post pictures of a 1985-1987('91) hydro bell housing yet.

Martin

 

[dyeager535]

GM part number is 15530202. Actually still available last I checked.

Link doesn't work for me here, but should be a scan of the hydraulic clutch components http://dyeager535.topcities.com/partsmanual.html

Note that the service manuals link page on some other website (can never remember, I always just search chevy truck service manuals and find it) also has the PDF's of the later parts manuals, where I got the above scan from.

Edit: This IS the early NV4500 with the correct input bearing retainer diameter, right?

 

[campfire]

Can you post a pic of the older style hydro bell placed on the front of the NV4500? I would like to see how far off the holes are.

Sorry, Kenny. I totally misunderstood what you were asking for. And this is the second time I've done that in this same thread.

Yes, I'll post those pictures.

 

[campfire]

I haven't seen you post pictures of a 1985-1987('91) hydro bell housing yet.

Martin

We'll all agree that I'm confused here, but I've been confident that my bell housing matches the description. If not P/N 15530202, what part number should I be looking for?

 

[campfire]

GM part number is 15530202. Actually still available last I checked.

Link doesn't work for me here, but should be a scan of the hydraulic clutch components http://dyeager535.topcities.com/partsmanual.html

Note that the service manuals link page on some other website (can never remember, I always just search chevy truck service manuals and find it) also has the PDF's of the later parts manuals, where I got the above scan from.

Edit: This IS the early NV4500 with the correct input bearing retainer diameter, right?

Link is dead for me, too. Are you saying I should be using part number 15530202? 'Cause that's what mine says...



The tranny is the older style (from approximately 1993). Input bearing retainer fits older bell housing quite nicely:






Neither excessively loose nor excessively tight.

 

[dyeager535]

Pretty sure there is no other P/N. I'm not aware of any variations from this for the 465/hydraulic setup.

If you google 15530202 and look at images, you will see a few pictures. You'll have to follow the links to see if they are actually that part number, and even then, being the internet, can you trust the descriptions? lol

Part number is probably no longer valid, although some places are listing it for ~$300.