Stiff shifting 3rd and 4th gear

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elefantrider

elefantrider

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The trans shifts good in the lower gears but 3rd and 4th are notchy shifting.

I recently put in a new MH FAG layshaft ball bearing, a very thin kicker shaft shim and am currently running ATF fluid.

Any idea what it could be, especially since the problem is only apparent in 3rd and 4th gear, on both downshift and upshifts?

If feels like a tight clutch but shifts fine in 1st and 2nd.

I have played with the clutch adjustment, and the primary chain has the correct tension.

Will try a different oil before I tear into it again.
 
Yeah - that's the first thing I'd try - different oil. Different oil makes a big difference in our manual tranny car and might do the same on the commando. FWIW, with Motul gear oil shifting was notchy and would sometimes grind into 2nd, Redline MTL eliminated it (both gear oils of the same weight). Not saying either is better than the other for any specific application, just that different gear oil can have different characteristics in different transmissions.
 
If its just started then the usual suspect is the last job you did, could it be the shim causing drag?
 
Never rode it before the layshaft bearing upgrade.
I just switched out a thicker kicker shaft shim for a thinner one to increase end-play but it still has the same problem.
Added in a little M1 synthetic gear lube. Same problem still.
Will try swapping the ATF for Sta-lube conventional gear oil.
 
baldy said:
Had similar problem. The dogs on the gears were worn.
Click to expand...
You had the problem on upshift and downshift also? As it is only happening on 3rd and 4th gear changes, I am thinking the problem is on these gears only.
 
You said notchy, are the gears crunching or is it the lever that is stiff?
 
Will try swapping the ATF for Sta-lube conventional gear oil.
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You have been running ATF in the gearbox? Mind if I ask why, isn't the purpose of 85-90 etc dedicated gear oil to handle the gears?
Just curious what reasoning process you went through to put in ATF?
 
i have heard of a famous racer and engineer on commandos , using a thicker oil in the gearbox to increase the cushioning between gear pinions (EP 140). Also a pal of mine who has been campaigning a commando grass track outfit for many years add a drop of STP in the box to achieve the same thing . i really cant get my head around using ATF . I have seen others on this forum say they do also why ??
 
1up3down said:
Will try swapping the ATF for Sta-lube conventional gear oil.
-------------------------------

You have been running ATF in the gearbox? Mind if I ask why, isn't the purpose of 85-90 etc dedicated gear oil to handle the gears?
Just curious what reasoning process you went through to put in ATF?
Click to expand...

Probably because I have used it for many years.

ATF in the Norton gearbox.
Less drag. Helps shifting.
ATF is a better lube for bronze bushings than GL oil. I have found the mainshaft sleeve gear bushing definitely lasts longer.
ATF contains seal conditioners that help keep the seal rings in a Norton box soft.
ATF is a very good gear lube. It has been the lube of choice in Mercedes standard gearboxes since the 50's and in many over the road truck manual boxes.
And by the way, an automatic transmission contains more gears than a manual box. Jim
 
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Jim, interesting ATF in your gearbox! Would you then recommend that any Commando owner also use ATF? You have listed lots of positives and no negatives.
For as long as I have been on this forum along with buying your products through CNW I have trusted your advise, I have to admit ATF in gearbox shocks me.
Surely then CNW also uses ATF in their gearbox as it is superior to regular gear oil?
 
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All I can tell you is I have had good luck with it. I've been running it for over 20 years in my Norton and a lot longer than that in dirt bikes. [But lots of people think I'm nuts.]
I started using it in my Norton when I was racing.
I doubt that CNW uses ATF. I don't think I have ever talked to Matt about it.
 
I have often thought about running ATF in the tranny but even though it is quite true that many manual trannys have been using ATF for years and there are, indeed, gears in a typical automatic transmission, I worry that the gearbox, originally made for a lower HP engine would be better off with a bit more "cushion" between the gear teeth. Jim's (and other's) experience indicates that it isn't an issue!
 
I was trying to eliminate having to clean up gear oil on my garage floor, usually nasty stuff. So when I saw Comnoz was using ATF, I jumped on the opportunity. Plus, as I also run ATF in the primary, I can see if my engine crank seal is leaking oil into the primary when wetsumped.

Now that I'm using Andover's X seals, leaks are gone but I haven't yet gone back to full gear oil.
 
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MexicoMike said:
I have often thought about running ATF in the tranny but even though it is quite true that many manual trannys have been using ATF for years and there are, indeed, gears in a typical automatic transmission, I worry that the gearbox, originally made for a lower HP engine would be better off with a bit more "cushion" between the gear teeth. Jim's (and other's) experience indicates that it isn't an issue!
Click to expand...

If the problem is down to the grade of oil, why is it only tight in third and fourth ? "A bent shift fork will cause that problem. Jim"
 
comnoz said:
All I can tell you is I have had good luck with it. I've been running it for over 20 years in my Norton and a lot longer than that in dirt bikes. [But lots of people think I'm nuts.]
I started using it in my Norton when I was racing.
I doubt that CNW uses ATF. I don't think I have ever talked to Matt about it.
Click to expand...

Is there a specific quality you use, or do you know if one can use any old ATF? (I don´t mean old as in "used"....)
 
The first thing I would try is to loosen up the primary chain. In my estimation, the chain can be very sensitive. Then go to the exotic things like gear oil, etc.
 
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