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Hard Shifting NV4500, less than 2 years on clutch

DieselAmateur

Diesel or Bust
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Quick update, will take time to post pics later but...

IT'S ALIVE! HALLELUJAH! This whole friggin time the problem was something to do with the pedal being worn out and not pushing the master far enough.

I'll post videos too but I don't really see much slop in the pedal bushings itself, so I don't know precisely where the issue started, or if the pedal itself bent just enough over time to shorten the rod travel distance enough to make this an issue.

I set my adjustable rod 1 1/4" longer than the stock 7 7/8" length from end to center of the eye hole that connects to the pedal, and this pushed the pedal way up towards the seat. I backed it off one end all the way and while it still sits a bit above the brake pedal, it's nothing I can't drive with at the moment. I'll pull it and get a precise measurement in the next few days, could end up I only needed an extra half inch or so of travel. And for the sake of being professional I'll have to put in some kind of small clip retainer on the rod between firewall and master, as there's nothing stopping the pedal from being pulled all the way up towards the seat. The replacement rod had a c-clip on a groove in the rod to prevent this.

Thanks to everyone for helping on this confounding repair. Bonus points to @Twisted Steel Performance for having it correct as the rod being the issue and an adjustable rod being the answer.

Glad to end 2021 on a good note, happy new year everyone and here's to a much better 2022! 🤘🍿🎉
 

schiker

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Nice! Congrats on a job well done. Should last a long time. Enjoy the handshaker as a nice functioning one is cool.

Yeah, I hear ya KISS Keep It Stupid Simple is generally a good policy but he did have a compound problem: broken stud ball, and the clutch disc did have a broken spring (not major contributor but not good either).

For GM clutches I am still in the mind of go big - replace everything involved that is important because the little things can get ya. This is just going to make me work on the pedal assembly or MC plunger mechanism the next time I do clutch as well as all the other stuff.
 

Husker6.5

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IT'S ALIVE! HALLELUJAH! This whole friggin time the problem was something to do with the pedal being worn out and not pushing the master far enough.
And what did I say a few posts back about how it would suck if all of this work and head banging over "soft" pedal feel and the clutch not releasing and all that time time spent bleeding and rebleeding the system completely and new line and cylinders replacement and rebleeding yet again and everything came back to wear in the pedal assembly preventing full actuation of the MC and thus keeping the SC from completely moving the throw out bearing fork?

Glad at least you're making it an adjustable linkage. That way, as your clutch pedal assembly keeps wearing out and gets more slop in it, when your clutch starts dragging again you can just crank some more "new assembly" into the linkage.

The "confusion" on correct pedal assembly is because there were some major changes to the floor pan/firewall stampings between 94 and 95 model years (for instance, 95+ seats don't bolt into 94 and earlier cabs) and you have to go off of the date of build to male sure you have the correct part(s).
 

Will L.

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Hydraulic clutch is almost always a fight. It isn’t like you have to look for people to have horror stories. GM, Ford, Dodge, Toyota- on and on- they all have major issues down the road. It is a space saving move for manufacturing ease and nothing to do with what works better. Hydraulic clutches behind 6.5 is the main reason I prefer automatic, that and the long term maintenance cost is higher with manual.

Glad yours is useable again.
 

DieselAmateur

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Yes if a simple cable/ z bar swap was possible with minimal mods, I'd do so in a heartbeat. I don't like the several more moving parts in the external slave system as more parts means more can go wrong, but being able to replace the slave without pulling the trans is certainly nice.

I'll take some videos and upload, but there really isn't much discernible play in the pedal. Remember I did the clutch in April of 2020, and it shifted wonderfully after that. Whatever is going on with the pedal came out of nowhere. And it seems that even the slightest play in the pedal can have a massive effect on the slave travel, making this a very hard problem to isolate.

Here's my custom hardware store master pushrod. 5/16" turnbuckle with grade 8 5/16" master end ground down to the neighborhood of 1/4" with grade 8 locknut
IMG_0978[1].JPG


As mentioned earlier the plastic bushing for the rod to pedal fits into the eyelet pretty much perfectly

IMG_0975[1].JPG

However with this end being left hand thread for the turnbuckle, I couldn't add a locknut, hence the duct tape on the prototype in the first image

When I installed the prototype, the pedal end fit but didn't click into place fully. The stock master is flat on both sides, not rounded like the eye bolt, so grinding flat will be necessary for a precise, worry- free fit

The stock master rod is 7 7/8" long, from master end to the center of the eyehole. I made my prototype 1 1/4" longer to start, so 9 1/8". This worked but pushed the pedal WAY up and forwards towards the seat. So with the rod already in place, I backed the rod on the pedal side of the turnbuckle all the way down snug to the eyelet. Just judging from the picture, this was at least half to 3/4 of an inch taken out of the rod, if not a full inch. I'll pull tomorrow and get a precise measurement.

What I think this will show is that even the slightest amount of free play in the pedal can have massive effects downstream.

What I might do is find the exact amount of length needed for my application and then modify another rod permanently for this new length. My hardware store turnbuckle isn't a complete hack job, but it wasn't designed for this application, and I don't know how the metal will hold up to regular long term use

here's a stock rod that I cut at the transition from 1/4" to 3/8" thickness. I bought two ~3/4" long fine thread couplers and cut 1/4" fine threads into the rod, thinking the two couplers would give me enough extra to push the master. But after having to back my prototype down so much I'm thinking I may need only 1/2" of additional travel to get things back into spec

(It's only mocked up on the tape measure, not welded/ ready for install)

IMG_0974[1].JPG
 

DieselAmateur

Diesel or Bust
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I'm glad it worked out for you... I'll send ya a bill later 🤞

Let this be a lesson to all, never be in such a hurry and start throwing parts/money at something, just think about the whole picture...
I just picked up what looks like a very clean optimizer take- out, so if you've got room for another engine project of mine in the future you can tack it on then ;)

And I certainly hope this thread can get anyone in the future to check their darn pedal and rod first before loading up the parts cannon
🙃
 

jrsavoie

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Yes if a simple cable/ z bar swap was possible with minimal mods, I'd do so in a heartbeat. I don't like the several more moving parts in the external slave system as more parts means more can go wrong, but being able to replace the slave without pulling the trans is certainly nice.

I'll take some videos and upload, but there really isn't much discernible play in the pedal. Remember I did the clutch in April of 2020, and it shifted wonderfully after that. Whatever is going on with the pedal came out of nowhere. And it seems that even the slightest play in the pedal can have a massive effect on the slave travel, making this a very hard problem to isolate.

Here's my custom hardware store master pushrod. 5/16" turnbuckle with grade 8 5/16" master end ground down to the neighborhood of 1/4" with grade 8 locknut
View attachment 70077


As mentioned earlier the plastic bushing for the rod to pedal fits into the eyelet pretty much perfectly

View attachment 70078

However with this end being left hand thread for the turnbuckle, I couldn't add a locknut, hence the duct tape on the prototype in the first image

When I installed the prototype, the pedal end fit but didn't click into place fully. The stock master is flat on both sides, not rounded like the eye bolt, so grinding flat will be necessary for a precise, worry- free fit

The stock master rod is 7 7/8" long, from master end to the center of the eyehole. I made my prototype 1 1/4" longer to start, so 9 1/8". This worked but pushed the pedal WAY up and forwards towards the seat. So with the rod already in place, I backed the rod on the pedal side of the turnbuckle all the way down snug to the eyelet. Just judging from the picture, this was at least half to 3/4 of an inch taken out of the rod, if not a full inch. I'll pull tomorrow and get a precise measurement.

What I think this will show is that even the slightest amount of free play in the pedal can have massive effects downstream.

What I might do is find the exact amount of length needed for my application and then modify another rod permanently for this new length. My hardware store turnbuckle isn't a complete hack job, but it wasn't designed for this application, and I don't know how the metal will hold up to regular long term use

here's a stock rod that I cut at the transition from 1/4" to 3/8" thickness. I bought two ~3/4" long fine thread couplers and cut 1/4" fine threads into the rod, thinking the two couplers would give me enough extra to push the master. But after having to back my prototype down so much I'm thinking I may need only 1/2" of additional travel to get things back into spec

(It's only mocked up on the tape measure, not welded/ ready for install)

View attachment 70079
Get a left hand threaded nut. Fastenal or anywhere should be able to get them. Ebay? Amazon?
 

jrsavoie

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I wonder if LH threaded nuts is standardized, like NC and NF threads or like metrics ?
I am pretty sure they are.


 

Husker6.5

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Left handed nuts come in both SAE Coarse and Fine as well as Metric Coarse and Fine. Our neighborhood True Value carries a good assortment of left handed nuts in its pick-a-pack section of individual nuts, bolts, screws, washers, fasteners, rubber stoppers, cable pass throughs, bushings, springs, etc. Every decent hardware store should have them.
 
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