NP435 grinding gears
Thread Starter
|
Postmaster
Joined: Feb 2008
Posts: 2,658
Likes: 5
From: Out of here
NP435 grinding gears
Ok, my NP435 has been getting harder and harder to shift lately and I knew that the slave cylinder was leaking slightly.
It used to get a little better by topping off the clutch master cylinder and today I finally decide to change the slave.
No difference in shifting! Now, I know that the input shaft isn't stopping completely. I can feel/hear it and it grinds like a SOB. Even if I push the clutch and wait a long time, it still grinds when trying to get it into any gear.
Next is to replace the clutch master cylinder and see if that helps.
It seems like the arm doesn't move enough to fully disengage the pressure plate.
How much travel would be sufficient to stop the input shaft? It seems like the rod is only coming out of the cylinder about 1/2 - 5/8 of an inch. The clutch only engages/dis-engages right off the floor. There is very little travel in the pedal.
What else would cause this besides maybe a sticky pilot bushing?
I really don't want to pull the tranny and transfer case unless I really have to.
It used to get a little better by topping off the clutch master cylinder and today I finally decide to change the slave.
No difference in shifting! Now, I know that the input shaft isn't stopping completely. I can feel/hear it and it grinds like a SOB. Even if I push the clutch and wait a long time, it still grinds when trying to get it into any gear.
Next is to replace the clutch master cylinder and see if that helps.
It seems like the arm doesn't move enough to fully disengage the pressure plate.
How much travel would be sufficient to stop the input shaft? It seems like the rod is only coming out of the cylinder about 1/2 - 5/8 of an inch. The clutch only engages/dis-engages right off the floor. There is very little travel in the pedal.
What else would cause this besides maybe a sticky pilot bushing?
I really don't want to pull the tranny and transfer case unless I really have to.
Super Moderator
Joined: Apr 2004
Posts: 34,491
Likes: 2,806
Is the firewall flexing where the clutch master is mounted? This is a feature of '80s trucks. There was a factory bracket available, but it's no longer available so you have to make your own. Have someone work the clutch and watch the firewall/pivots etc. Soaks up a lot of travel and causes issues like yours. Also, where the slave mounts might be a wobbler too, so look at that while someone works the pause pedal.
Thread Starter
|
Postmaster
Joined: Feb 2008
Posts: 2,658
Likes: 5
From: Out of here
Yeah, I've heard about the infamous flexing "feature" but I just swapped my cab over recently and there was not a spot of rust on it. It is mint. That's why I changed it.
I could see an older rusty, weak or split firewall allowing this to happen, but I can't see it being the problem in my case but I'll check it anyway.
This sucks.
I could see an older rusty, weak or split firewall allowing this to happen, but I can't see it being the problem in my case but I'll check it anyway.
This sucks.
Cargo Master
Joined: Mar 2007
Posts: 2,935
Likes: 34
From: Arcadia, Fla
I have the same problem on my 84 F250, found out air got into the line causing problem. After 2 quarts of brake fluid(trying to bleed air out) and lots of fussing, I came to the conclusion the master cylinder failed, But It never lost any fluid at all! Some how air leaks into the system.
Ever tried to pull a 37' motorhome with the clutch pedal on the floor?? Not fun at all...
Of all the past 18 years having that truck, this is the 2nd time it failed.
Ever tried to pull a 37' motorhome with the clutch pedal on the floor?? Not fun at all...
Of all the past 18 years having that truck, this is the 2nd time it failed.
Trending Topics
Super Moderator
Joined: Apr 2004
Posts: 34,491
Likes: 2,806
Yeah, I've heard about the infamous flexing "feature" but I just swapped my cab over recently and there was not a spot of rust on it. It is mint. That's why I changed it.
I could see an older rusty, weak or split firewall allowing this to happen, but I can't see it being the problem in my case but I'll check it anyway.
This sucks.
I could see an older rusty, weak or split firewall allowing this to happen, but I can't see it being the problem in my case but I'll check it anyway.
This sucks.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
Thread Starter
|
Postmaster
Joined: Feb 2008
Posts: 2,658
Likes: 5
From: Out of here
Well, it seems as if I have fixed the problem.
Today I replaced the clutch master cylinder and now it shifts like butta! Still a little hard down shifting into second, but if I hold the shift lever while rolling to a stop it drops right in.
No more grinding in first while at a stop and reverse is really nice as well.
This weekend I'm going to change the fluid in it, and it should hold me over until I pull the transfer case and tranny to change the rear main seal.
Right now it's easier to just keep putting a little oil in her every once in a while and as an added bonus: I don't have to cut the grass in between the two strips of concrete in my driveway where the grass used to be.
One word of caution: While my old man was helping me bleed the slave, he was in the cab pumpin' the pedal and I was underneath with the allen wrench. I cracked the bleeder open while he had it pumped and brake fluid shot out the side vent hole and right into my freakin mouth!
It's a good thing that it didn't shoot me in the eye instead. That would have been painful.
Today I replaced the clutch master cylinder and now it shifts like butta! Still a little hard down shifting into second, but if I hold the shift lever while rolling to a stop it drops right in.
No more grinding in first while at a stop and reverse is really nice as well.
This weekend I'm going to change the fluid in it, and it should hold me over until I pull the transfer case and tranny to change the rear main seal.
Right now it's easier to just keep putting a little oil in her every once in a while and as an added bonus: I don't have to cut the grass in between the two strips of concrete in my driveway where the grass used to be.
One word of caution: While my old man was helping me bleed the slave, he was in the cab pumpin' the pedal and I was underneath with the allen wrench. I cracked the bleeder open while he had it pumped and brake fluid shot out the side vent hole and right into my freakin mouth!
It's a good thing that it didn't shoot me in the eye instead. That would have been painful.
Cargo Master
Joined: Aug 2007
Posts: 2,558
Likes: 69
From: New Zealand
Did the mechanical clutch linkage crack the firewall too, or only the hydraulic version.
When my AOD gives out, I'll go manual - I don't have a problem with the mechanical set-up, if it's reliable & prevents the firewall cracks
When my AOD gives out, I'll go manual - I don't have a problem with the mechanical set-up, if it's reliable & prevents the firewall cracks
Super Moderator
Joined: Apr 2004
Posts: 34,491
Likes: 2,806
Probably an issue either way, as the force and action of the clutch pedal is held by the firewall. You can make a reinforcement with a little effort and patience and scrap steel.
BTW if you go manual, both the Mazda & ZF 5 speed ODs use the juice clutch.
The older 4 speed od can use a manual clutch, but I wouldn't go to all the work of a conversion and put one of those in.
BTW if you go manual, both the Mazda & ZF 5 speed ODs use the juice clutch.
The older 4 speed od can use a manual clutch, but I wouldn't go to all the work of a conversion and put one of those in.
Super Moderator
Joined: Apr 2004
Posts: 34,491
Likes: 2,806
ZF comes in 3 flavors:
SBF, fits the 302, 351w, 300 six
BBF 385, fits 429/460, 351m/400
Diesel.
Pics here:
Domestic Truck Tranny Guide
SBF, fits the 302, 351w, 300 six
BBF 385, fits 429/460, 351m/400
Diesel.
Pics here:
Domestic Truck Tranny Guide
Thread
Thread Starter
Forum
Replies
Last Post
john.clark
Pre-Power Stroke Diesel (7.3L IDI & 6.9L)
13
Oct 12, 2015 03:14 PM
rando76
1983 - 2012 Ranger & B-Series
12
Apr 16, 2015 11:48 AM
