IMCO extreme failures
 

Anyone had one fail? I did! Took out the tower, shift fork, all the gears & bearings in the upper case.
I filled it with oil, but it looks like a oil related failure. The drive lube monitor was full at the time of failure, but empties after it failed.:mad:
Any ideas? It only ran for 10 minutes, but I bought it used. I instected it prior to instilation & all appeared to be in good working order.

I can say this they suck break all the time. Finally getting my new Bmax HT. Ours broke in the first hour on a brand new boat. No warranty sent it back charged us up the wazzu and then it vibrated so bad we had to have another marina service it. I will never touch another drive of theres over this deal. Funny part is our spare XR that is a reman lasted all season. Our tower went also looked like a bad gear broke of fell through destroying the tower. It honestly broke with no abuse 800 rpms idle 30 mph turning around.

Also no signs of heat no discoloration on anything.

I had an Imco Extreme SC upper mated to stock Bravo lower on my Pantera. 550hp, 5200lb boat and 275 hrs and was still going strong. Never had a single issue.

Imco uses the Merc gears and Merc had a batch of bad gears with a lot of failures in the XR's as well.

Jason,
what kind of power in what size boat? Does it have XR or XZ type gears? How did u fill the drive? You say you inspected it, did you tear it down or just peek inside? Where is the worst heat damage located, lower (fwd) gear and inner bearing? What is the running history, or should we say, how were you driving it prior to and at the time of failure. Give me a general run down on the 10min life of this thing..

If it were a heat/oil related problem, you may have had an air pocket somewhere..

I have rebuilt two SC Extremes, that had XZ gears in them and they held up fine. So they are not all junk. The insides are mostly Merc. If they are over powered or abused or assembled wrong, anything can break.
I am sorry to hear that you had a failure. I know what it is like to buy something and expect it to be "better" and it fails.. :(:(

Tell us more about what you find inside.. that may help locate the problem..

I found a broken verticle drive shaft in the upper, melted bearings in the tower & cap. The gears were "useable" on the pinion & lower, bu the upper was blue as blue could be.
I think it air locked, but I did fill it from the bottom so who knows. All the orings were perfect & it did not leak anywhere we could find.
I'm just going to have to say that I did not get it filled all the way, although it ran out the top hole.

Thats filled all the way...??? Did you see the 4 uppers for sale?

How could you fill it any more?

Sounds like it could be an air bubble.. but it definitely sounds like a lack of lube problem..

Nope. I think I need them!

Seems common for that drive, I had it happen to me twice before getting rid of them.

The first time it chucked a tooth on the upper drive gear. The second time it chucked a tooth and wiped out all the bearings in the upper.

I cut my losses, had the drives fixed and sold them. :(

Wierd, it is all Mercruiser stuff in there.

From what I saw the only non-mercury part was the small caged bearings on the clutch shaft. The upper case is supposed to be really strong but it still has a "pressed" tower, it's about a 3/4" deeper than a standard XR tower. The upper cap seems stout but I didn't have the patience or the $$ to keep wasting. $10K in drive repairs was enough for me to make a switch.

While it's apart, it might be a good idea to replace the bearings in the drive gears with the max machine caged bearings. They apear to be a heavier bearing. I never got to use them because I sold it.

Jason,
after it ran out the top hole did u put the plug in and continue to fill it till the bottle filled up?? Or did u top off the bottle? I let the bottle drain with the drive and then fill it from the bottom. If you did it this way. Not sure why there was an air pocket at the top. There is a natural flow to the oil in the drive and there maybe a blockage in that path.. oil is pumped up to the top thru the top cap and down on the upper gear..
I asked Dock Holiday to fwd u an email I sent him, with some suggestions..

Hope this helps.

I filled the drive from the bottom up & then topped off the bottle.
Are you saying to fill it up to the top of the plug & then coninue to fill it till the bottle is full?

Yes! When you see fluid start to come out from the top plug
stop and let it sit for a few mins so any air bubbles can come up. Then put the plug in, Take the cap off the fill bottle,
continue to fill from the bottom til the bottle is full. I always
put the boat in and check the fluid after I have idled out for
a while. (before getting on plane). The fluid is thick and even
after doing this you may have to add a little to the bottle. hope
this helps. Timmy.

Yes Jason,
As Timmy said.. fill till it comes out of the plug then plug it and continue filling till it comes up in the bottle. Wont hurt to let it burp some before you continue to fill. And another thing, you could tilt the drive up and let it burp. .. Under the lower gear, where the tower is, an air pocket can form there.. Although I have never had a problem with it. I have seen drives melt down the lower gear bearing and tower.
I always fill as tfarmer said, but dont wait for it to burp. But my bottle is empty and the cap is off so it may be burping thru the bottle.
D*ck