NV4500 Swap into Stock 6.2 Diesel / TH400 / NP208 M1028/M1008 - COMPLETED

[erasedhammer]

I think you'll be ok. I think I'm having issues because I went the the AA recommended centerforce clutch setup. Luckily I have all the 6.5 clutch bits from the truck the trans came out of, so I'm going to take some measurements. I'm also headed out to pickup a 6.2 flywheel and the 6.2 clutch release arm and throw out just to see if something can be made to work.

My issue seems to be both too much preload on the throwout and not enough travel. It seems like the centerforce clutch needs more travel than I could give it to get a nice engagement point. I can shorten the rod to releieve some of the preload but that would just make the throw out bearing travel issue worse...

Check this out, 6.5 clutch fork next to the AA provided one (also GM, I think its an older mechanical linkage type) View attachment 817878

Slave cylinder mounting area is about the same, if not just slightly more inward (which would make for more throw out bearing travel) as well as the throw out bearing end a bit further out (also more travel). I think the 84 style fork will mount in the AA bell housing whereas this 93 fork needs a special stud. To be continued when I get back from the parts store...

Not sure if I shoudl spin off my own thread or keep posting here? I don't want to muddy the waters as this thread started off as an excellent resource for what you need to do the swap and here I come posting about my issues and trying different things..

I still have to have someone actuate the pedal while I watch my fork travel, but when I did have the slave cyl adjusted so it didn't have any preload on the pressure plate, the full travel of the pedal (to the floor) would not disengage the clutch as I could not put it in gear with the engine running.
So at least with my luk flywheel and south bend clutch kit I would assume the small amount of preload is just necessary.

I've put about 500 miles on this swap now and I dont have any gear grinding issues when shifting. Reverse is usually a good indicator of this since its not synchronized.

I would spin off your own thread documenting your clutch/flywheel/slave cyl setup and link it back here so others can follow if they so choose.

 

[shotty]

Reverse should be synchronized in your trans. Mine isn't, originally, but you can swap in the synchro bits and do that, which is what I did. I also ditched the 1-2 interlock that was only found in the early trans as well.

 

[erasedhammer]

Reverse should be synchronized in your trans. Mine isn't, originally, but you can swap in the synchro bits and do that, which is what I did. I also ditched the 1-2 interlock that was only found in the early trans as well.

1998 trans, no synchros on reverse. It does have the 1-2 speed lockout.

 

[erasedhammer]

Not sure if I posted these pictures already, but here is the TO bearing at its maximums. With the fork against the rim of the bellhousing opening (towards the rear) the TO is almost past the input shaft sleeve. Theoretically, the clutch should be disengaged at that point if not before. If not that's AA's fault.
This is for the later year AA trans bellhousing though.

 

[erasedhammer]

Fork has just a sliver of space left bottoming out the master cylinder. Clutch is fully disengaged just before the pedal hits the floor.
I'm going to attempt to adjust the rod to try and get the TO bearing to have 0 preload in a couple weeks (trucks going in for a gasket overhaul soon).

 

[Mad Texan]

I have cleaned up where the clutch master cylinder should mount and only found one noticeable dimple instead of three.

 

[erasedhammer]

I have cleaned up where the clutch master cylinder should mount and only found one noticeable dimple instead of three.

Could you take a photo further away?

 

[Mad Texan]

Could you take a photo further away?

Here’s a shot further back...

 

[Black Ops]

I have cleaned up where the clutch master cylinder should mount and only found one noticeable dimple instead of three.

Hydraulic clutch wasn't used until 1985 so 1984 trucks probably won't have the dimples for the clutch master cylinder.

 

[Mad Texan]

Hydraulic clutch wasn't used until 1985 so 1984 trucks probably won't have the dimples for the clutch master cylinder.

It could be that. I've been told mine is definitely an '84 because of some features on the ambulance body. I'll have to make a pattern of some sort.