NP435 Noise

I should have just left well enough alone.
Finally got the driveshaft back in the 1980 1ton tonight after installing the gear vendors a couple months ago. It had been parked about 30ft from the shop ever since trailering it to get the driveshaft measured.
Went to drive it in the shop and received this noise after putting it in first and releasing the clutch. Put it in 2nd and didn't get the noise so crawled it into the shop. Dropped the driveshaft from the gear vendors end so it wouldn't go anywhere and tried putting it in first again just to rule out the driveshaft. Didn't give it any gas but same noise (this is the recording).

What I did prior to this:

Drained the transmission
Cleaned the gunk off the magnet
Gears all looked really good (maybe not now...)
Remove the tailshaft housing and replaced it with the gear vendors adapter
Installed gear vendors
Filled transmission with amsoil

The transmission hump cover is still off.
Sounds like the noise is coming from the transmission and not the gvod.
Didn't have this noise prior to doing this work.

Thoughts? I know it sounds like the gears aren't meshing but I can't think of what I'd have done to cause this.

SoundRecord-2021-03-26-22-53-13.wav

kramttocs wrote

Thoughts? I know it sounds like the gears aren't meshing but I can't think of what I'd have done to cause this.

SoundRecord-2021-03-26-22-53-13.wav

I know it sounds bad, but the fact that you shut it down so quickly I doubt anything is damaged. It would almost have to be something in the GVOD wouldn't it?...I mean, you didn't technically didn't touch anything in the NP435?

That would make sense to me also but I don't think there is anything in the gvod that would make that noise. I can call them on Monday though.
I think I will drain the np435 tomorrow, pull the side panel and look around.

Sounds like a gear not truly engaged.  Jut touching.  And I agree, I doubt that you damaged anything.

Before going to all the trouble of draining and pulling the cover, what about shifting it through the gears?  And maybe even driving it, slowly in the other gears?

How exactly does the GVOD operate? (engage)

Could be crappy synchros 1st to 2nd that you never heard before because of the gearshift boot and stuffing.

Cory, the tailshaft housing's centering bushing is not there any more.
It could be an alignment issue with the overdrive unit, or it could be that the overdrive is loading the output shaft axially.
And this has left one set of dogs with zero clearance.

I'm sure Scott will figure it out.
If he does drop the overdrive and reinstalls the tail shaft he may still hear it with the cover off.
In which case the problem has been there all along.

I'm not sure how the layshaft's set up in a New Process box.

I feel for you, Scott. No idea what the noise is but hoping you're able to resolve the problem quickly and without much difficulty.  

OK now a owner of a NP435 after the T18 that was in my truck would not shift into gears at times and made a lot of noise.

Anyway When you had it in low, granny gear, and let the clutch out I bet the truck did not move right?
Did you try and see if the shift lever would go a little bit more into gear?
I am thinking you did not and it would have.

Mine is hard to get into, and out some times, of granny gear. I think it may be in gear but it did not go in all the way. Because I have driven the truck enough I kind of know when it is not in all the way.

Also being you don't have the floor pan in place why not pull the shift tower as it will give you a better picture of what is going on inside the transmission. That is how I seen the T18 was trashed and needed to be rebuilt or replaced.
You can see all the gears and other parts a lot better than from the PTO port on the side of the transmission.
Dave ----

BTW I hope that Amsoil  is not rated for GL5 use the oil has to be only rated for GL4 or it will hurt the yellow metal parts in the transmission.

Thanks guys. Really appreciate the replies (and the vote of confidence Jim). I started to respond at least 4 times this weekend but I was jumping from job to job and never was able to fully type out a thought.

I will keep this to the point. If I was to list all the questions that went through my head this weekend on this, it would be a mess

I backed the truck out to swap places with the 86 and reverse sounded fine. Pulled it back in using 2nd. It definitely didn't make the noise like 1st did although I felt like I was starting to hear it if I gave it a little gas. Let off quickly and didn't test anymore.
Despite this truck being a bare metal floor I absolutely agree with Jim that without the cover, sounds are going to be "off" somewhat.

Drained and filtered the oil. No chunks and the gears looked the same. There were some shiny shavings on the magnet though. Looked all over, put it in the gears, and nothing stood out. Due to the increased thickness of the gvod adapter I had to get new bolts but, as it did on install, the three [hint] I could easily see where flush with the case.

Drained the gvod and removed it. Oil looked good there as well. Pulled the adapter. Found that the bottom driver side bolt had been ground down some. Found a few reports of this happening.
While embarrassing since I was concerned with this during install and mistakenly assumed if three were good the other was also, if this is the issue I will be happy. This would explain the shiny shavings on the magnet.

That's as far as I've gotten though I did pick up an adapter gasket today.

Jim - Regarding the gvod, this will explain it better than I could dream of.  I haven't hooked up the electronics so for awhile it will only be direct drive. I think the alignment concern is valid so I took some measurements but everything seemed to be the same as with the original housing. The adapter actually still has a bushing in relatively the same place. Instead of the yoke, it's the coupler that joins the tailshaft to the gvod input shaft that uses the bushing. Not sure how much sense that makes without seeing it in person.

Dave - that's a great question. I never gave it gas in 1st with the driveshaft connected but can't recall now if it tried to more forward or not. I was too focused on stopping the noise that the truck could have been levitating and I doubt I'd have noticed. Even with the adapter on and putting it in first, the stick seemed like it went all the way as normal. Also having my wife shift it and me looking through the side, the gears seated as I'd expect. That makes me think it would have moved in first and the noise was truly just the reverse gear.
GL5 and GL4 for these transmissions. Now isn't that a nightmare to figure out  I got lost a couple months ago trying to figure out what's I should use. Ended up just calling Amsoil and for better or worse they recommended this gear oil. It is GL-5 but also says it can be used in GL-4 diffs. Not sure if that means anything in regards to transmissions though and the yellow metal. Short answer - I really don't know, it may be a mistake to use it.
On the cover, I may still do that if this bolt isn't the whole issue. Is it as simple as removing the bolts and lifting off?  The shop manual makes it seem so.  Will anything go flying or falling?



I will dig out my cheap ebay scope to check how much I need to grind off the adapter bolt so it doesn't contact the reverse gear.
I would have expected to hear the same noise when entering 2nd gear and especially reverse. I will have to get my wife to shift through the gears again as I don't know what moves and what doesn't regarding that reverse (idler?) gear. My fear is that it shaved off what was needed for that clearance and the grinding noise is elsewhere. My hope is that it is still too proud and is preventing that gear from moving full travel. So maybe it's not a matter of two gears not meshing properly but rather a third gear not getting out of the way [of 1st gear].

If the gear oil says it is okay for yellow metal, or meets both GL-4 AND GL-5 you are fine with Amsoil.

When GL-5 first came out it used a lot of chlorine extreme pressure additives, which eat up zinc (in brass)
Any reloader* will tell you not to use something like Brasso in your case tumbler. (pretty much the same thing)

If the bolt was hitting a gear I think you've found the culprit.
Could it be that reverse is turning on the layshaft when 1st is engaged?

Anyway, I know these units are uncommon so I hope your teething problems are solved.  

It must be great to have the truck back under its own power.
Spring is here. It's time for Chanute to get to work.

I agree with Jim - you've found the problem.  Well done!  

"think"

ArdWrknTrk wrote

"think"

Yup.

As for how much needed cut off, it was around a 1/4" like the guy in the other forum.
Maybe if I'd been a little more observant I might have noticed the thicker flange for that bolt on the original housing


Got it all put back together and that noise is gone so that's good. That had to be putting quite a lot of pressure on that gear.
Bad news is that there is still a noise that I need to track down. I will have to drive it some more to find the specifics like at what speed, etc. but I do know that when going a decent speed if I push in the clutch it's still there.
That rules out a few things but still leaves the main changes: gvod and driveshaft
I checked the ujoints when I got back from a drive and they were cool to the touch.
I am leaning towards output bearing and that this noise is just more pronounced now.
Will drop the driveshaft to do some more elimination.

One more layer peeled.  

And on to the next

Pretty sure it's my output bearing going out and probably has been for awhile but just now really noticing it (tranny cover is still off). I dropped the driveshaft and put my stethoscope on it. Really sounds like it's coming from back there, plus it makes sense if the noise is still present on the road even if I push in the clutch pedal.


Dave - what rebuild kit did you use? I see US Standard has some as well as Novak-adapt. Prices are all over the place though for what looks to be the same components.

Name's not Dave () but I've gotten good service from Midwest Transmissions.

Thanks Gary. I called them earlier today.
Having a hard time making sense of the pricing from the various companies/retailers.

Midwest and Novak at both at 300 while USA Standard (Summit) and JBG are 160-170.

The kits all look the same to me but that's a significant difference in price.

It's probably the difference in name brand bearings and seals (Timken, SKF, NSK, FAG) and no-name bearings.

While that may not make a difference to many, a reputable shop doesn't ever want to have to explain why a Dong Yua bearing caused a customer to end up stranded.
That's not to say the major brands don't manufacture in China. And it's not to knock the abilities of Chinese manufacturing either.
It is about reputation, quality control and the ability of a transmission shop to say they haven't cut corners, when they have a warranty issue.

I agree. Midwest probably uses their kits in their own rebuilds. They have a 12 month warranty on their transmissions.