[Fot] TR6 transmission rebuild - counter shaft gears, and somewhat related...

Tue Jan 9 08:57:37 MST 2018

 On the subject of the (very marginal) layshaft bearings, these will live a lot longer if the end-float is set to a minimum, and the oil changed frequently.
Every time it goes graunch, it's making metal, and those metal bits like to go right down into the bottom of the case and get caught between the backside of the thrust washer and the flat on the case, in addition to eating up bearing surfaces.
Short of somewhat involved machining, this will scrap an otherwise good gearcase.
Glen

-----Original Message-----
From: Glenn Franco via Fot <fot at autox.team.net>
To: fubog1 <fubog1 at aol.com>
Cc: FOT list <fot at autox.team.net>
Sent: Tue, Jan 9, 2018 10:37 am
Subject: Re: [Fot] TR6 transmission rebuild - counter shaft gears

I ran into this problem on 2 of the 3 transmissions with A-type overdrives I rebuilt in late November / early December.
What happens is the caged needle bearing on the smaller end of the laygear walks out of place and grinds its way into the small thrust washer that makes it almost impossible to remove.
It seems that the small circlip if used also fails allowing the bearing to move into the thrust washer.
In both instances we had to replace the case since the damage was so bad it destroyed the flat surface of the case. 
Since 4 speeds with out O/D are readily available we stripped down 2 to use their cases.
The last one I built was so bad and the washer would not come out. I had to wrap a chain around the cluster gear (layshaft) and use a heavy "Slugger" Body Dent Puller to get the laygear out.
I replaced that laygear as well.

I found this to be on the O/D transmissions but have not seen it on 4 speed only transmissions.

FYI
Glenn TR6, TR250, MGTC, BMW 2002 Roundie, Mazda Miata

On Tue, Jan 9, 2018 at 6:40 AM, fubog1 via Fot <fot at autox.team.net> wrote:

 What Steve said, this is the way to do it.
Also I recently noticed that Moss is selling a double bearing gear now.
Glen

-----Original Message-----
From: Steve Yott <tr4 at wi.rr.com>
To: van.mulders.marcel <van.mulders.marcel at telenet.be>; 'fubog1' <fubog1 at aol.com>
Sent: Mon, Jan 8, 2018 7:01 pm
Subject: RE: [Fot] TR6 transmission rebuild - counter shaft gears

For all gearboxes I rebuild and for a number of other builders I modify the lay gear by boring the 1st gear end in order to fit a double bearing which pretty much eliminates bearing and shaft failure.  There is too much load on the bearing and shaft in this area and the double bearing installation mimics the more durable Stag gearbox.  At the same time I machine a groove in the end to fit a circlip to prevent bearing walk.  I also use Loctite retaining compound to add a little further fixing for the bearings.

Steve Yott
Silver Lake Triumph Centre

From: Fot [mailto:fot-bounces at autox.team.net] On Behalf Of van.mulders.marcel--- via Fot
Sent: Monday, January 08, 2018 12:20 PM
To: fubog1 <fubog1 at aol.com>
Cc: fot <fot at autox.team.net>
Subject: Re: [Fot] TR6 transmission rebuild - counter shaft gears

These shell needle bearings are easily damaged : when the shell is warped a bit, it will fail. When the bearing is in place, one should check if the needles can be spinned freely.

A nylaton bush of the TR4a -TR6 inner wishbone bearing is great for pushing these shell bearings in place. These bearings are not secured by a circlip, contrary to the open cage needle bearings.

But the needles of the open cage bearings are running directly against the ev. worn or damaged inner surface of the laygear.

Marcel

Van: "fot" <fot at autox.team.net>
Aan: gblake58tr3 at icloud.com, "fot" <fot at autox.team.net>
Verzonden: Maandag 8 januari 2018 15:33:33
Onderwerp: Re: [Fot] TR6 transmission rebuild - counter shaft gears

It probably has the later type shell bearings and 1 or both have worked loose in the laygear housing bore and "milled" into the thrust washer (s).
Glen

-----Original Message-----
From: Greg Blake via Fot <fot at autox.team.net>
To: Fot <fot at autox.team.net>
Sent: Sun, Jan 7, 2018 8:56 pm
Subject: [Fot] TR6 transmission rebuild - counter shaft gears

I am rebuilding a TR6 transmission and ran into a strange snag. When I removed the countershaft the counter shaft gears did not drop to the bottom of the case. I had to tap on the counter shaft gear set with a brass punch to get them to move far enough to allow the input shaft and gear to be removed. Now that I have the main shaft out of the case, I can't get the counter shaft gears out of the case. I've been able to move them a little bit by tapping on the gears with a brass punch through the drain hole but I can't get them out. Has anyone run into this before? Any ideas to get them out?

Thanks. 

Greg

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