[Fot] TR-4 / TR-6 tranny layshaft bearing mod?

Tony Drews tony at tonydrews.com
Tue Nov 19 11:09:16 MST 2013


The Open bearing you describe - is that the bearing between the input 
shaft and the main shaft?

Thanks, Tony

At 06:20 AM 11/17/2013, Peter Vucinic wrote:
>Tony,
>You can purchase a modified Countershaft Gear Set form Rimmer Brothers. Moss
>probably have them as well?
>It is already machined to accept 2 bearings at one end. All the hard work
>has been done.
>
>Also, if your gearbox has the needle roller bearings that are captive in a
>steel outer. Get rid of this design and use the TR6 style of 'open' bearing.
>
>The early style of bearing with the steel outer will allow wear material and
>debris in the oil to locate inside this design bearing and cause premature
>failure. Not a good design.
>
>All the gear boxes I build I change to the later open style bearing and
>haven't had an issue as long as you regularly change the transmission fluid
>etc. Especially true if you have an Overdrive attached where you are now
>introducing wear material from the lining in the OD.
>
>I just freshened up a friend racing gearbox after 10 years of competition
>running with a J type OD attached. Lay shaft only had a few thousands of an
>inch wear.
>
>Hope that helps?
>
>Cheers...
>
>
>"You can Make a Small Fortune From Motor Racing. As long as You Started With
>A Lage Fortune!"
>Kind Regards
>Peter Vucinic
>TR-4
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>-----Original Message-----
>From: fot-bounces at autox.team.net [mailto:fot-bounces at autox.team.net] On
>Behalf Of Tony Drews
>Sent: Sunday, 17 November 2013 1:46 AM
>To: fot at autox.team.net
>Subject: [Fot] TR-4 / TR-6 tranny layshaft bearing mod?
>
>Has anyone modified the TR-4 / TR-6 tranny layshaft assembly to accept
>larger, higher capacity bearings?  Turns out the root cause of my
>transmission failure was the failure of the front needle bearing in the
>layshaft assembly.  Before I do the parts search / purchases, I thought I'd
>check to see if there's a longevity improvement that can be made there.
>
>It's been a while since the box was apart, and let me tell you - with a
>buggered up layshaft shaft the disassembly is challenging.
>
>I'll be replacing, input shaft, layshaft and 3rd gear at least.  Also had a
>weird failure where one of the pins that the spring slides onto in the
>overdrive is broken off - may have been an assembly issue.
>
>I may have most of the parts needed for the rebuild, we'll see what uncle
>jack's tranny parts stash includes.
>
>Cheers, Tony Drews
>_______________________________________________
>fot at autox.team.net
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