Topic: Mix/Match "noisey" and "quiet" gears...BigMike?

[SKULLYOTA]

The below quote is from BigMike in another thread, and my question references his points.

My question is: To what degree can I mix/match early and late transfer case parts?  I built a crawl box using a 1979 topshift and a 1985 forward shift.  However,  i mixed gears up a little.  Will mixing the "quiet" and "noisey" gears together make a difference?  I'm assuming the gears themselves are the same minus the quiet run gear plates BigMike talks about, and the gears will eventually "break-in" with their new mates and everything will be ok. 

I know for a fact i put the two forward most gears/bearings from the 79 case into the 85's housing #1 to make the crawl box, then the rear case uses the 79's housing except for #2, but the rest i don't remember.  The two front bearings and front input on the crawl box easily slide in and out a bit though....

The reason for this is that starting in 1984 Toyota redesigned the large gear on the counter shaft as well as the low speed idler gear to incorporate what we refer to as a "Run Quiet" design. These late mode gears have a thin sheet-metal-like pre-loaded gear plate that mounts directly & coaxially to each respective gear. Each thin gear plate (two in total) has exactly one less tooth count than the gear it is mounted directly onto. Therefore, there is only a specific area around the perimeter of each gear where the tooth of its mating gear lines up "in time" without interference. What happens is that while the gears are in mesh, the opposing gear forces this gear plate to rotate at a higher speed, as it has one less tooth, and because it is pre-loaded, it requires a minimum amount of force to remain in mesh. The result is that the teeth in contact are forever pre-loaded so that there is no noise from gear chatter (zero backlash). Hence they run quietly.

What typically happens is that one gear, for instance the input, is pulled out of the case in such a position that it is only in mesh with its opposing gear (and not also its gear plate). If the gears are then rotated like so without also remaining "in time" with the pre-loaded gear plate, then the teeth of the input will never allow the input itself to seat in proper position where it's bearing's snap ring is flush against the front of the transfer case, and any attempts at installing the transfer case behind the transmission will only result in difficultly and eventual damage to one -or both- "run quiet" gear plates. The trick in this case, as mentioned above, would be to slowly rotate the input shaft while applying pressure with your free hand on each bearing. Then, as each gear rotates and finds the specific area that is "in time" with the pre-loaded gear plate, the gear will suddenly fall into its correct position relative to the front reduction housing.

any opinions?

[SKULLYOTA [OP]]

anybody got an idea?

[Cheesemaker]

Shouldn't have any real issues that I know of.  I do know that the earlier, noisy gears tcase, is stronger.  I've been told this from Mike, and others in the industry.  But I'm not as technical as I'd like is all the little things of Toyota.  But in the end, the only real difference is the thin metal plate that keeps a pre-load on the gears to keep them backlashing on the quiet gears.

Hopefully Mike can chime in on this.  But I know that he is really busy at the shop.  From my understanding he is basically the head man running Marlin Crawler, along with Dave the Manager, and tries to leave Marlin in his think tank area. 

[slander]

I popped that plate off when i built my most recent crawl box as i could not get the gears to fit together (operator error on my part im sure ).  My gears chatter pretty good, but hey its worth it to crawl. 

[hamish_18]

So I think this is my issue as well. I get a lotttt of chatter when going down the highway. Some I think is from the triple stick setup.(If I hold the two outer sticks together with my hand by squeezing them together a little bit, the chatter sound is reduced) But when I let off the gas, I hear a BUNCH of chatter. Also in 4wd I get a lot of chatter too...

I am in the process of rebuilding them with all new bearings, and new input/output shafts to see if that helps. Even a new coupler and bearing for the adapter. If the sound doesn't go away, then I don't know what to do...

I also am thinking about getting the double-cardon joint put on my rear driveline too and re-degreeing the rear axle. Any other suggestions?