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Re: [TowerTalk] TRI-EX LM470 GEARBOX

To: "'Towertalk'" <>
Subject: Re: [TowerTalk] TRI-EX LM470 GEARBOX
From: "Mike" <>
Date: Tue, 20 Jul 2010 17:28:57 -0700
List-post: <">>

Valvoline 85W-140 Synthetic gear oil

This is the stuff I put in the Gear Reduction unit. Make sure you flush the
old stuff out.  Can't help you with the seals, as you will have to pull it
apart and look at size etc.

Mike, K6BR

-----Original Message-----
[] On Behalf Of K0DAN
Sent: Tuesday, July 20, 2010 4:56 PM
To: Towertalk
Subject: [TowerTalk] TRI-EX LM470 GEARBOX

Hi Folks...

I'm doing maintenance on my 1980's vintage Tri-Ex LM470D which I've had up 
at this QTH since about 1999.

It has the original a Hub City gearbox, which leaks oil. The gearbox has 
never caused me trouble, but it seems like having oil in it is better than a

dry gearbox.

A couple of problems/questions for the group...

A) The fill plug is very inaccessible (blocked by the bottom of the motor). 
The best I've come up with is a funnel with piece of plastic tubing and try 
to drip oil into the gearbox. 80 weight or higher weight gear oil is just 
too thick to run thru the curves in the plastic tubing. Even regular motor 
oil doesn't make it, and the small opening of the fill plug makes it hard 
for air to "burp" out of the housing. Result: lots of spilled oil and no way

to tell how much oil ever got into the housing! Any tricks on how fill the 
damn thing?

B) Has anyone replaced the gearbox seals? Is there a way to replace the 
gearbox seals without complete removal from the drum and mounting frame? How

does the gearbox shaft attached to the drum shaft? It appears to be welded, 
but I doubt this is the case...there must be a key on the shaft, however 
there are no obvious set screws, keys, or other means of coupling. Looks 
like complete removal could be a big job with collateral damage.

I can send some photos if my text doesn't make sense....anyone been down 
this road before? Any ideas greatly appreciated!

Tnx es 73



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