OUCH - broken u-joint fork driveshaft.

[IGKNIGHTED]

I got my ‘93 Excel out for the first time this year and 15 minutes on the water I heard a bang knock knock knock. I shut it down and checked my prop- nothing found. Re-started and same horrible sound.
I got a tow back to shore and found the u-joint bellows all torn up and could feel something loose inside.
Took it home and pulled the lower unit drain plug and nothing but water came out : ( I had changed the gear lube last fall.
i cut the bellows off and found the u-joint fork shaft broken off at the gear box and it flopped around damaging the case. I pulled the gear box off the top and the broken shaft end is still stuck in the gear.

So here are my questions- why did it break and where did the gear lube go? I’m guessing the gear box seal was damaged and water went in and lube out? The gear box shaft still spins but is it most likely toast? How about the lower unit- since the shaft broke it wasn’t spinning but did the water damage it’s?

Does my my set up have a gamble bearing that may have been damaged as well?

Its a Volvo Penta SP-C drive on 430B V6

 

[Scott Danforth]

no, the AQ series do not have a gimble bearing. you do have the PDS shaft bearings

here is some reading on the PDS shaft bearings https://forums.iboats.com/forum/eng...s-engines-outdrives/10343318-pds-shaft-issues

your u-joint shaft is toast. your transmission should still be in good shape.

expect to pay $1500 at a dealer, or look around on-line and on CL for a u-joint shaft. I managed to find a complete low-hour trans and new u-joint shaft for $200 on CL from a guy cleaning his garage.

 

[kenny nunez]

Pull the prop shaft then drop the lower gear case, there is a filter basket in the top of the gear case which will full of the shavings from the upper unit. The bad thing about an AQ is there is an impeller on the prop shaft which circulates the oil and the shavings when things go bad. Hopefully the lower may still be usable and just need a good cleaning. If the bearings are rusted or do not turn smooth start shopping. While the lower is rebuildable you may have a problem finding a shop with the some of the mandrels to replace the bearings or willing to do the job.

 

[Maclin]

Looks like the drive locked up solid at the top gears and the end of the yoke was the first weakest part. The lower could have locked up but, from memory, there is a coupler between the upper and lower shafts designed to shear first. That is what makes me think the upper locked up solid, and instantly. Spitballin'.

 

[Bt Doctur]

Same here, looks like the upper locked up

 

[IGKNIGHTED]

the upper gear shaft and gears still turned and I took it apart and the bearings are not seized but they are loose and noisy. Maybe they locked up, broke the shaft and broke loose again when the u-joint shaft banged around. There were no metal shavings inside. I just bought a used gear assembly with u-joints on eBay for $500 - hopefully that’s all I need. Still wonder where all the gear lube went and how the lower filled with water and if the PDS bearing was damaged.

 

[IGKNIGHTED]

Here is the end of the shaft broken off- look at how it twisted before breaking. Obviously locked in hurry but everything is spinning freely now. The bearings in the clamp box are toast- loose and noisy but they too are not locked up.

 

[kenny nunez]

You still need to check the inside of the lower. It is not hard to replace the prop shaft seals and there are no special tools needed. There are not many “O” rings on the AQs so they should all be replaced. You MUST pressure test the drive as a complete assembly. Unless you like buying upper gear cases.