Evaluating Tranny while off the bike?

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jjwithers
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Evaluating Tranny while off the bike?

Post by jjwithers »

I have two 4 speed transmissions that are off the bike(s).
They haven't been run in MANY years. Many could be 5 or more...

I can shift them through the gears nicely.

Both have transmission fluid drained.

However when i spin them by grabbing the input splines, one spins really easily and the other has more resistance (in comparison).
The one that spins easier has a slight amount of free play before engaging as i twist the splines back and fourth.

Hopefully this makes sense....

But i am thinking the looser tranny is in worse shape.

Are there any other ways to test the tranny while it is off the bike (without taking it apart)?
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Motorhead
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Re: Evaluating Tranny while off the bike?

Post by Motorhead »

Best method is explained in Duanes page

I use a clutch plate to get a better grip I'd think the tighter one the better of the 2

BUT it takes to install to prove any good and bench testing fooled me to install a tranny that poped out of all gears
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Re: Evaluating Tranny while off the bike?

Post by dwerbil »

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Re: Evaluating Tranny while off the bike?

Post by jjwithers »

I should have checked Duane's site first. I had no idea he had a page on it. It is very helpful. Thanks.
www.beemersandbits.com
'77 R100S - http://www.joshuawithers.com/r100s
'73 /5 Toaster Cafe bike http://www.joshwithers.com/slash5
'67 Bridgestone 175 Hurricane Scrambler
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jjwithers
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Re: Evaluating Tranny while off the bike?

Post by jjwithers »

I employed my wife as a transmission spinner and tested the two 4 speed transmissions i have lying around.
One (the one with more slop in it) spun freely and the only suspect issue is that it has a quick double click when shifting from 3rd to 4th.

The other was almost stuck and wouldn't spin very well. My wife couldn't spin it so after i took over as the spinner, i realized it would get stuck at a certain point. i finally broke it free and it still had a 'sticky' feeling to it upon certain rotations. I feels as if some of the gears are gummed up at a certain degree and when they mate with other gears, it creates a hesitation or sticky feeling.
My suspicion is that somebody put the wrong transmission fluid in it and it got all gummy inside.
I'm thinking that - - Either a run it and do a few flushes with new transmission fluid...
or the transmission should be rebuilt....
www.beemersandbits.com
'77 R100S - http://www.joshuawithers.com/r100s
'73 /5 Toaster Cafe bike http://www.joshwithers.com/slash5
'67 Bridgestone 175 Hurricane Scrambler
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'72 BMW 2002
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Duane Ausherman
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Re: Evaluating Tranny while off the bike?

Post by Duane Ausherman »

Be very suspicious of that sticky transmission.

A bench test will not test for jumping out of gear.

If you were to bench test a couple dozen in one day, then you would have a "feel" for it. Sorry it can't be described in words.

It is very possible that a transmission will test OK and be junk. If the bench tested transmission shows problems, then it has problems. You can get a false positive easily, but don't bother to install it if it can't pass the bench test.

Many tests are like that, however, they can still serve you well.
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Re: Evaluating Tranny while off the bike?

Post by ME 109 »

How much information regarding the condition of a tranny can be gained from what is on the magnetic drain plug?
If no bench or road test is available.
Last edited by ME 109 on Mon Aug 06, 2012 2:06 am, edited 1 time in total.
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Re: Evaluating Tranny while off the bike?

Post by robert »

Until you open the gearbox and have the parts on the bench, you are making wild ass guesses and waisting your time trying to figure out the problem.
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Re: Evaluating Tranny while off the bike?

Post by Deleted User 287 »

ME 109 wrote:How much information regarding the condition of a tranny can be gained from what is on the magnetic drain plug?
If no bench or road test is available.
If you have big pieces of metal you need to open it up. I think that is about the only not-false reading you can get from the magnet.

Milk in the coffee is never good.

So is NO drain plug... :D
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