1-2 Shift Clunk

[fhubler]

Quick transmission question on a '48 D24 with fluid drive (stock).  Everything works great, 1- R shift is smooth & quiet as is the 2-3 shift.  When I come out of 1st gear on the way to 2nd I get a noise, sort of like a clunk, at varying degrees of intensity.  I just changed what I am pretty sure must have been the original gear oil in the transmission & rear.  It seems to have helped & I continue to shift through the gears in an effort to work the new gear oil into everything.  I still have to clean & lubricate the shift linkage.  Anything else I should consider?  Could this be a shift linkage wear or adjustment issue?

 

Edited November 22, 2017 by fhubler
missing word

[1949 Wraith]

It could be a wear or linkage alignment issue, also cleaning and a good lube might help.

As you are driving, try putting the shift lever into third before you shift up into second and see if that smooths it out. If that doesn't improve you could have gear wear.

Edited November 22, 2017 by 1949 Goat

[greg g]

What lubricant did you use?  The gear oil recommended for the three speed manual transmission has a GL 1 rating.  New lubricants (GL 3 and higher) are formulated with anti shear components required by hypoid gear sets common to newer transmissions.  These are not friendly to brass and bronze components that are used in the synchronizer parts of your transmission and will damage those parts.

Are your engine mounts all in good candition?  The clunk could be coming from worn components allowing the engine to move more under load, and then clunk back into normal position as you shift.

Read you gear oiloil label carefully to assure it is correct for your application.

[normanpitkin]

Check the fluid  drive reservoir and top up as needed

[busycoupe]

Is the clutch fully disengaging? It sounds like it may be dragging slightly. 

[fhubler]

Thanks to all for your responses.

First, let me reiterate that the oil that was drained from the transmission was really bad, but I did not see much metal in it.  After changing the oil with a synthetic 75W-90 oil, I noticed a substantial improvement.

Every other shift sequence (1-R, 1-3, 3-2, 3-1, 3-R) is silent & effortless.

I did top off the fluid drive coupling with universal tractor fluid.  This made no difference.

I will look into the gear oil specifics & see what I can find out.

I am quite sure the engine mounts are original & in need of replacing.  I will put that on the list.

The shift linkage is very cruddy.  I will thoroughly clean it & inspect it for wear.  I would assume, if there are bushings in the linkage, they will also need to be replaced.

* On an unrelated note, the automatic hyperlinks that kick in when typing certain words for these posts are the most aggravating thing I have encountered in a very long time.  Does anyone know how to turn them off????????????????????

[busycoupe]

If you find out how to turn off the automatic hyperlinks please tell everyone how to do it.  I think that a lot of us are plagued with them.

[fhubler]

The hyperlink itself isn't a big deal, but the curser jumping to the beginning of the word is maddening - especially if you know how to type. 

[greg g]

 

Read your gear oil label carefully to assure it is correct for your application. When I was looking for mine I read of two synthetic s that claimed to be compatable.  One was Royal Purple, can't remember the other but google and see.  Then a call to their tech lines would put your mind to rest.  But I found some Castrol gl 1 and got three QTS.

[fhubler]

I have an inquiry into the tech line...

For an update on the car, I got into it a little more tonight.  I noticed that the only time it makes the unhappy noise is when going between 1st & neutral.  Some of the rough treatment seemed to be coming from the shift lever mechanicals on the column.  I noticed that the clamp was rotated clockwise a few degrees.  Loosening the screws & rotating it back to level with the floor made everything move much more freely.  I pulled the whole mechanism apart & found it completely dry with noticeable wear on the shifter pivot barrel screw, some wear on the push-pull pin on the shift lever & noticeable wear on the shift rod where it goes through the steering column support under the dash.  I lubed all that stuff up & put it back together strait & now the shifter moves very smooth & freely.  I moved on to the linkage & found a great deal of slop in all of the rods at every pivot & in the bell crank pivot center point as well.  I'll have to clean all of that stuff up before I can see what parts are involved.  The linkage on the transmission itself feels fine & everything seems to be moving normally inside of the transmission.

[1949 Wraith]

In my 1938 transmission I am using Amsoil 15-40 Synthetic Diesel oil, that was recommended by George Asche . Works nicely and is quite different than the 90w winter and 160w of the owners manual.

If anyone is interested US Napa stores do carry GL1 90W, its cheap at around $11 for a gallon.

[Ajgkirkwood]

Sorry to hijack the thread. But i have a question about my trans aswell. Im a 3 on the tree. When gearing up its fine. I have to go from 1 to 2 at under 10mph or i get a grind. But down shifting i grind pretty much all the time. From 3rs to 2nd i have to be going like 10mph or i grind and from 2 to first pretty much at a roll or less. It feels like my clutch has no play where the lightest amount of movement on the pedal and im already disingaging. I think theres a link to adjust that (rod with nuts? ... That sounds wrong) but any ideas if my trans is normal or not? I pretty much cant down shift unless im coming to a light. I can down shift to second for a turn but ill be going pretty slow around the turn just to gear down

[busycoupe]

First gear does not have synchros and will grind unless you are stopped, or nearly so.  From your description it sounds like the second gear synchros are worn.  You might try double clutching when down shifting from third to second to help line up the synchros for a smoother shift. 

[greg g]

Your clutch pedal should have an inch and a half to two inches of free play before the linkage starts to do its thing.  The job of the synchros is to stop the input shaft from turning when the gears are selected.  If the clutch is dragging slightly it is turning the input shaft slightly making selection of first or reverse a grinding experience.  To test this, with the clutch pedal down, momentarily select second before trying to grab low or reverse.  This will engage the synchro, stopping the input shaft and making your shift from neutral to low or reverse grunchless.  If so you need to lengthen the rod that goes to the throwout fork.  Quarter inch at a time or so till the grind goes away.  

Edited November 23, 2017 by greg g

[Ajgkirkwood]

Its fine gearing up. It kinda feels like when i push the pedal all the way down it still seems kinda engaged? I have tried double clutching but no go. It might be cause of how monkey around it was getting the 265 in from the owner before me