Low whining sound from undercarriage

[Hib Halverson]

Originally Posted by Paul Workman

The 90s have straight cut gears in the ZF which produces some gear whine, especially in 1st and 2nd, I find (in my 90 as well).

(snip)


There are no "straight cut" gears in any version of the ZF S6-40.

Gears in the early 6-40s have a slightly smaller helix angle and that's why the early transmissions are a little more noisy and have a little higher input torque rating.

[Paul Workman]

Originally Posted by Hib Halverson

(snip)


There are no "straight cut" gears in any version of the ZF S6-40.

Gears in the early 6-40s have a slightly smaller helix angle and that's why the early transmissions are a little more noisy and have a little higher input torque rating.

A picayune distinction, to be sure, Hib.

[Dynomite]

Originally Posted by Hib Halverson

(snip)

There are no "straight cut" gears in any version of the ZF S6-40.

Gears in the early 6-40s have a slightly smaller helix angle and that's why the early transmissions are a little more noisy and have a little higher input torque rating.

I find that information very interesting....thanks Hib

[Hib Halverson]

Originally Posted by Paul Workman

A picayune distinction, to be sure, Hib.

Granted, you've got me beat on the vocabulary front. I had to look up the meaning of "picayune".

Nevertheless, Paul, if you knew a bit more about manual transmissions you'd not say that.

I'd like to suggest that when you're making statements about subjects on which you lack accurate information, maybe you should think twice about commenting.

[Paul Workman]

Originally Posted by Hib Halverson

Granted, you've got me beat on the vocabulary front. I had to look up the meaning of "picayune".

Nevertheless, Paul, if you knew a bit more about manual transmissions you'd not say that.

I'd like to suggest that when you're making statements about subjects on which you lack accurate information, maybe you should think twice about commenting.

Oh... THIS certainly went off the rails! It isn't going the way I intended! I meant no disrespect, Hib. OK, I'll admit in jest I was just "pokin' the bear" a little, but thought you'd "get that" - that I was really giving you a sort of a "left-handed" compliment.

(edit): Everyone...should think twice before saying stupid, derogatory, and unfounded chit on an open forum. Especially the two of us.

Sorry for the misunderstanding, Hib. (Shoulda taken my meds first.)

[Dynomite]

Originally Posted by Hib Halverson

(edited)

Gears in the early ZF S6-40s have a slightly smaller helix angle and that's why the early transmissions are a little more noisy and have a little higher input torque rating.

Regarding the ZF S6-40 ZR-1 Transmission.......I find that that the smaller helix angle (of the gear teath) attributing to a little more noise and higher input torque rating is of technical interest and worth documenting........something not described before

[grahambehan]

The change made to helix angle as mentioned by Hib was a significant change to radiated gear mesh frequency because it increased contact ratio, ie the number of teeth in mesh. There are detail changes to tooth profile and flexibility that affect the load progression across the teeth and thereby reduce the noise generated as the gears mesh also.

Graham

[WARP TEN]

Originally Posted by grahambehan

The change made to helix angle as mentioned by Hib was a significant change to radiated gear mesh frequency because it increased contact ratio, ie the number of teeth in mesh. There are detail changes to tooth profile and flexibility that affect the load progression across the teeth and thereby reduce the noise generated as the gears mesh also.

Graham

As usual, the voice of knowledge and reason. Thanks Graham --Bob

[Hib Halverson]

Originally Posted by Paul Workman

Oh... THIS certainly went off the rails! It isn't going the way I intended! I meant no disrespect, Hib. OK, I'll admit in jest I was just "pokin' the bear" a little, but thought you'd "get that" - that I was really giving you a sort of a "left-handed" compliment.

(edit): Everyone...should think twice before saying stupid, derogatory, and unfounded chit on an open forum. Especially the two of us.

Sorry for the misunderstanding, Hib. (Shoulda taken my meds first.)

Ok. I did misunderstand the context. Sometimes, that happens when we can't see or hear each other, but I'm still smarting from having to go to my dictionary to look up "picayune".

[Hib Halverson]

Originally Posted by Dynomite

(snip)something not described before

The change was made mid-year 1993, as I recall. Without trying to find some of my old S6-40 articles I can't say for sure. Graham remembers more about that change than I, so maybe he can confirm the time line.

The early S6-40s were designed when GM was still considering a turbocharged LT5 for the future and it wanted some extra torque capacity. After it became obvious there never would be an LT5TT, GM decided to address customer complaints about noise and decided to increase the helix angle as well as the other changes Graham details. The decision resulted in the later transmissions which were quieter and made less noise.