So I think my np435 has a bad bearing or something.. when using it to hold back in first or reverse it makes quite a loud grinding sound. My problem is I have no idea if it's normal because I have never heard or driven another one

I went and picked up an engine and tranny today and it has a t-18 transmission on it. I also have another np435 I could put in. Anyone know if there are any advantages to each of these? The t-18 was out of a 77 so I think it still has the non-syncro granny first.

 

Moved to proper forum.

A T-18 would have a non synchro 1st gear. A T-19 would have a synchronized 1st gear. I drove a T-18 for years with no problems.

Are you sure the "grinding sound" is not just normal gear noise? They do make a lot of noise in 1st or reverse.

 

what about oil level? they do make noise too so it can be hard to tell.

 

The NP435 is unsynchronized in first gear as well. 1st to second gear there is always a grind. most people don't even use 1st unless they are pulling because of how low it is.

 

I guess a 'howl' would be the accurate description. When in first, especially if you are using it to slow you down (or you just let off the gas after accelerating) it makes quite a loud howling sound. Same thing in reverse. I expect some noise but this does sound a bit excessive to me.. but like I say I don't know.

 

some do howl. but check the oil level.

 

At what speed would you say you are slowing down or accelerating in 1st? The NP435 is the lowest 1st compared to the T-18. Both are very good truck transmissions.

If you replace, might as well go with the other NP435...as there is no advantage going with the T-18. JMHO...

biz

 

The oil level is good, I check it once in a while.

I never really drive it in 1st or reverse much above idle. If you idle on a slight grade where the truck goes faster than the gear, or it starts to bounce a bit, you can hear it howl. It always makes noise, but it's worse when the output is faster than the input.

I was looking at the two transmissions.. I haven't cleaned up the t-18 yet but unless it's actually a t-19 and has a syncro first I think I'll put the np435 in.

Thanks!

Ian

 

1st and reverse in a 435NP use "straight cut" gears - not helical - and they share the same spot on the countershaft gear, so they make lots of noise.

This howl doesn't happen in any other gear?

If it's truly too loud, I'd suspect the rear countershaft bearing (the one taking most of the load when in 1st/reverse), or worn teeth.

1st and reverse are not syncronized, and if someone who didn't know that tried to get into 1st when moving maybe they sheared off half the teeth

If it's truly bothering you, open the top (or remove the PTO cover) and look inside and see if you can see any gear damage.

art k.

 

Yeah it's only noisy in first and reverse. This truck was used as a farm truck for the past 20 yrs or so and I'm sure this is where it has spent most of its time. I'm going to see if I can find someone else who has one of these or has driven them to see if it's normal. I do expect it to make more noise because of the straight cut gears, but this doesn't sound right to me.

Thanks!

Ian

 

I have a T-18, and it makes noise as well. You can hear it in every gear. You can even hear it when you push the clutch in and leave the tranny in gear. Of course, without hearing yours, it's tough to say.