There should be very little clearance between the two surfaces. It does flex under load and the gimbal should support it from flexing too much. The wear occurs as you trim it up and down while under load. On a LH prop drive the wear is on the opposite side. I cant remember if they thinned the drive housing to add the thickness of the plastic shim. But you could add it and take up some of the clearance. Either way if there is too much clearance the drive will flex and wear out the new parts in the transom.
I added a SS plate to the gimbal to take up some clearance and I think that is why it broke. The two small screw holes must have been a source for a fracture to start. So that isnt a good idea. They used to add the SS plate to TRS drives, that is were I got the idea.
Cig, is the 1/4" clearance on both sides or just one? When you raise the drive up and down does the clearance change??

Dick

Cig, is the 1/4" clearance on both sides or just one? When you raise the drive up and down does the clearance change??


the boat is still covered up but if I remember correctly it was even thru and thru.

I just took a look at my drive, it has the plastic wear pads, there is no clearance between the upper housing and the gimbal ring. I would take another close look at it and find out why you have more clearance. I just measured the distance from the outside of the wear pads on several upper housings.. they measure Min of 4.000" up to about 4.020". Ones that I just installed new pads on.. would be 4" in the front and widen a bit to the 4.020" in the back where the pin is snapped into the housing. On a drive that has used wear pads with little wear showing, I measured 4.010" along the entire surface. So 4" is what you want to see on the OD of the wear pads surfaces and about the same on the ID of the gimbal wear surface.
That should lead you to where the problem might be. I am not sure if the new gimbal is sized to the newer housings (with wear pads) or if they made the upper housing different.
But I would investigate if I were you.. the 1/4" gap is TOO much and eventually will cause a, (as I was told by Merc, when ever a drive breaks off) "Catastrophic reaction"!!
And believe me.. you dont want to experience it, if you dont have to..

Hope this helps..
Dick

have you checked the toe out/toe in adjsutment; my old TRS drives wore excessively on the outboard plates when there was excessive toe-in, good luck -jeff

I ended up having the drive welded. If was then ground flat. I used a file to remove a small amount at a time. It took about 20 tries to get the drive on. The clearance is tighter than the factory. I would be surprised if its .001-.002.
I am still looking at other drives and this will be used as a spare in the near future.

Did you add the plastic wear pads? That would prevent the problem in the future.
If a competent welder, did the welding, I would feel confident with that fix. Also make sure your hing pins are in good condition..

Yes I paid someone to weld this. They could not think of a way to create the slot for the plastic pad. I added a brand new gimble ring so all the bushings are brand new. I am still looking for a drive and will use this as a spare.
Thanks for all your help.