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

[erasedhammer]

Oof that's a tough question these days.... I know you weren't asking me but I figured I'd chime in, I paid $300 for a set of hydroboost pedals. Cleaned and painted them and managed to find some new bushings on ebay as well. I also had an almost 1/4 inch deep slot worn in the clutch pedal pin, so I welded that up and made sure to use some grease putting it back together.

Yeah, these things are definitely going for a lot!

 

[Mad Texan]

How much did you get your pedals for?

I found a hydroboost set for $180 that have some wear on the pin. I'll either weld it up or replace the pin. I'll have to see how tight the bushings are when they get here...

 

[shotty]

Question.. I'm wrapping up my swap now, but I have the 712577 bell housing because I have a 93 transmission. I think everything else is the same as yours though. As it sits, with the bell housing bolted on, the slave cylinder is adjusted so the wedge is as close to the cylinder as possible. There is about 1/4 inch or so behind the clutch arm and the bell housing where it goes in and the rubber boot sits. This seems like it isn't enough but maybe its just my inexperience with a setup like this.

How much travel do you get on your slave cylinder pushrod? I haven't got my clutch bled yet but it really does feel like I don't have enough travel...

 

[erasedhammer]

Question.. I'm wrapping up my swap now, but I have the 712577 bell housing because I have a 93 transmission. I think everything else is the same as yours though. As it sits, with the bell housing bolted on, the slave cylinder is adjusted so the wedge is as close to the cylinder as possible. There is about 1/4 inch or so behind the clutch arm and the bell housing where it goes in and the rubber boot sits. This seems like it isn't enough but maybe its just my inexperience with a setup like this.

How much travel do you get on your slave cylinder pushrod? I haven't got my clutch bled yet but it really does feel like I don't have enough travel...

Are you using the napa master/slave cylinder set? did you get the AA kit to adapt their clutch fork to the napa slave cyl?

With the AA kit, I adjusted the two nuts on the push rod so the fork sits about in the middle of the threaded section. I can take a picture this afternoon if that helps.
I found the fork should be pressing down the pressure plate fingers a little bit to have the clutch grab near the bottom of the pedal.

 

[shotty]

Yeah I got the 715535 slave cylinder mount from AA and the slave cylinder I snagged from rock auto for an 85 chevy, pretty sure its the same. I can probably adjust the wedge to about the same position and apply some pressure to the plate. About how much throw do you have on the slave cylinder when the pedal is pressed? I'm wondering if I need to grind out a bit behind the arm.



I dont have a thick flywheel, just a LUK 6.5 replacement one, but it does seem kinda tight there if the slave cylinder moved the arm more than a small amount.

 

[shotty]

Here's a shot from underneath, you can see how much clearance there is behind the arm and the bell housing. This is with the throwout bearing installed and resting on the pressure plate, with the slave cylinder rod adjustments all the way towards the slave cylinder. Without grinding, I can get about 1/2 inch of movement on the slave cylinder pushrod before the arm hits the bellhousing

 

[erasedhammer]

Yeah I got the 715535 slave cylinder mount from AA and the slave cylinder I snagged from rock auto for an 85 chevy, pretty sure its the same. I can probably adjust the wedge to about the same position and apply some pressure to the plate. About how much throw do you have on the slave cylinder when the pedal is pressed? I'm wondering if I need to grind out a bit behind the arm.

View attachment 817750

I dont have a thick flywheel, just a LUK 6.5 replacement one, but it does seem kinda tight there if the slave cylinder moved the arm more than a small amount.

I had a buddy pressing the pedal while I watched the slave cyl. It doesn't take a whole lot of movement to disengage the clutch.
I'm not sure the single mass flywheels vary.

In the picture I have in post #6, picture named 219-slavecylnotadjusted-jpg, you can see the fork is all way the down the threaded portion of the slave cylinder rod. In that position, with the pedal fully depressed the clutch will NOT disengage. If you position the fork half way up the threaded rod, the clutch should grab at a normal position on the pedal throw.

 

[erasedhammer]

Here's a shot from underneath, you can see how much clearance there is behind the arm and the bell housing. This is with the throwout bearing installed and resting on the pressure plate, with the slave cylinder rod adjustments all the way towards the slave cylinder. Without grinding, I can get about 1/2 inch of movement on the slave cylinder pushrod before the arm hits the bellhousing

View attachment 817751

That is wierd, can you take a picture of the slave cylinder bracket where it attaches to the bellhousing?

 

[shotty]

Here you go

 

[erasedhammer]

Here you go View attachment 817752
View attachment 817753

I'll have to take some pics of where my clutch fork is sitting. Mine fully engages and disengages the clutch, no interference from the bellhousing.
I don't believe you should have to grind the bellhousing. What clutch kit did you buy? There are two kits for the two different years of the nv4500. You have to buy the kit that matches the year of your transmission. (The clutch pressure plate fingers are different lengths)

 

[shotty]

What clutch kit did you buy? There are two kits for the two different years of the nv4500. You have to buy the kit that matches the year of your transmission. (The clutch pressure plate fingers are different lengths)

I have the Centerforce 165552 pressure plate and the 383735 disc, ordered off of the products suggested on https://www.advanceadapters.com/pro...95-gm-nv4500-5-speed-adapter-bellhousing-kit/ tech vault.

 

[erasedhammer]

I have the Centerforce 165552 pressure plate and the 383735 disc, ordered off of the products suggested on https://www.advanceadapters.com/pro...95-gm-nv4500-5-speed-adapter-bellhousing-kit/ tech vault.

Did you get the same flywheel that I got? LUK LFW201.

 

[shotty]

I have a LUK LFW126.. Looks like the 126 is for the 6.5 and the 201 is for the 6.2. I am under the impression both are intergangeable.

 

[erasedhammer]

I have a LUK LFW126.. Looks like the 126 is for the 6.5 and the 201 is for the 6.2. I am under the impression both are intergangeable.

It actually looks like I have about the same distance as you.
I'm going to snag someone to operate the pedal while I record the fork moving

 

[shotty]

Ordered a 6.2 flywheel to compare to a stock 6.5, since the 6.2 is heavier I'm wondering if it's thicker..
In the meantime I'm going to bleed my clutch and see if the current setup can actually release the clutch or not. How did you go about bleeding the slave seeing as how the bleeder screw is pointed right at the oil cooler lines...

Edit.. Clutch bled but the clutch fork hits the bell housing before the pedal bottoms out. The trick to getting it bled is to unmount the slave cylinder from the bell housing, remove the reservoir cap, crack the bleeder and let fluid just drain down until it comes out the bleeder. Then close the bleeder and pump the pushrod on the slave, forcing the air bubbles up and out (with reservoir cap removed). Eventually it gets nice and firm and you can mount it back up and you're done. Don't even need two people!

The good news is that after bleeding it does release the clutch disc before the fork hits the bell housing. After bleeding the slave, I had to use the nuts on the mounting stud to pull it onto the mount, forcing the rod all the way in even with the adjusting nuts bottomed out. This put a bit of tension on the pressure plate, perhaps too much.

It seems like I would need to clearance the back part of the bell housing for the clutch fork, which would solve the fork bottoming out before the pedal, but not do anything for the preload I have to put in to the throwout bearing just to get things mounted up.

More edit.. Went out to see where in the pedal travel the clutch disengaged to find that it would no longer do that... So I pulled the bellhousing to make sure the pressure plate was bolted down all the way and it is.. A bit lost for now, going to call Advance Adapters tomorrow and see what they have to say.

 

[chevymike]

Sounds like you have a short throw out bearing and you need a long one. I ran into this problem on another build I did.

 

[shotty]

Sounds like you have a short throw out bearing and you need a long one. I ran into this problem on another build I did.

I was thinking about that, and Novak has a great reference page with throw out bearing measurements and part numbers, but if i put a longer bearing on then it would move the at-rest position of the fork even closer to the slave cylinder, and its already too far forward. I have the adjusters all the way down towards the front and the fork is still preloading the bearing on the pressure plate fingers. As far as I'm aware you should have a small gap between the bearing and the fingers so that its not engaged all the time.

 

[Mad Texan]

Curious about the issues your having as I'm a few steps behind. I went with a Luk 04-902 clutch kit and the Luk FW201. I can take some measurement to compare if needed.

I'm wondering if you could add spacers on the bolts between the slave and the AA adapter to get more room on the adjustment rod...

 

[shotty]

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)

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..

 

[chevymike]

Yeah, that was my next thought, if the TO bearing is not the issue, is the fork wrong for the application. Transmission swaps are always fun. LOL