80 series transmission noise

[Jack_K]

I installed an 80a kit in my Nautique 200 after the 40a trans suffered a cracked drum. My first replacement had a noticeable ruff sound in reverse but went into gear smooth. the replacement under warranty had a loud clunk into gear but sounded fine otherwise. I received a 3rd replacement and it has the same clunk into gear. now I'm being told that is normal for the 80 tranny. I would like to know others experience with newer boats or replaced transmission.

[BigRedSV211]

I did the same conversion in my sv211. There is zero clunk in either direction.

[Rednucleus]

Check that your prop is properly seated & undamaged undamaged key - have seen that make a clunk that sounds similar

[jpwhit]

Yes, that clunk is definitely something the 80a does in the 200 until it's broken in. When I replaced the 40a with the 80a in my 200, that was immediately noticeable. I talked to PCM about it and they said what was normal with the 80a and it would go away after the transmission was broken in. And sure enough, noticed it for a while and then the next season, we realized a few weeks in that the noise was completely gone. It's been about 800 hours since the 80a was installed, it's been flawless.

[Jack_K]

Thanks jpwhit that's good to know. Hopefully mine will do the same. I've been told it's normal but not that it will go away and it's very noticeable.

[Jack_K]

I would like to add that the first 80a tranny was quite into gear but reverse had a ruff sound in gear as if backlash/clearance was tight. the next two replacements have a loud chunk into reverse but normal after in gear as if too much backlash/clearance. PCM/Velvet drive says clunk is normal. Metal hitting metal can't be good if that's what it is. being some are quite, some are ruff, some are clunky into reverse it would seem a quality/engineering problem exists at Velvet drive that isn't being addressed much like the 40a cracked drum known problem.

[jpwhit]

I'm good friends with a guy that owns pretty busy boat repair shop that works on Mastercraft's and Nautique's. He's installed a lot of 80a transmissions. His experience has been the 80A is much better designed and robust transmission than the 40A. He's put in a ton of 80A's and has seen very few issues with them.

[gary s]

Aren't these transmissions hydraulic? Any gears that are in it are planetary- always in mesh not shifting or sliding into mesh? I've had my 40 apart, similar in operation to a Velvet drive

[jpwhit]

Aren't these transmissions hydraulic? Any gears that are in it are planetary- always in mesh not shifting or sliding into mesh? I've had my 40 apart, similar in operation to a Velvet drive

Yes, thats right.

The clunk sound is coming from shaft end-play tolerance. When the transmission is new and not broken in, the shafts are a little tight fitting inside the inner bearing races. So the shaft doesn't slide very easily when going between forward and reverse. So when there is enough force, the shaft breaks free from the inner race and moves suddenly by the amount of the endplay tolerance and makes a clunk sound. Once it's all broken end, the shaft floats more freely and the shift of the endplay tolerance between forward and reverse happens more smoothly.

There is also a specific amount of gear backlash tolerance in all the planetary gear sets. And that's important for long term longevity and to account for thermal expansion. As the gears bed into each other as they break in, that smooths out quiet a bit as well.

[Jack_K]

ok jpwhit lets say you're right. Is there a fluid that would be better like royal purple or an additive that would help the shaft move easier? I still say this is like an old transmission with varnish built up causing it to stick. New tranny shouldn't be this way. my first 80a replacement had ruff sound like planetary gears too tight, also not good.

[jpwhit]

My recommendation would be not to do anything other than drive the boat and let it break it.

[Jack_K]

jpwhit you talk like you work for pcm/velvetdrive. That fit should have been fixed at assembly.

[jpwhit]

Nope, worked as an Engineer and Software developer in the large scale industrial market before I retired last year.