Severe chatter

Ford whisperer

Ford whisperer

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My ‘51 ford f1 had an annoying habit of popping out of second gear, so I found a credible builder with loads of experience with these three speed side shift transmissions to go thru it with a keen eye looking for any worn parts. He replaced the synco hub, installed new shims wherever needed, and declared it all ready to go. After I installed it with a new clutch disc, pressure plate, throw out bearing, etc., and drove it out of my shop about 50’, there was a scary chatter felt thruout the truck. I pulled back into the shop and let it all sink in. Something must have been altered with the trans rebuild. One thing I noticed when installing the drive shaft is I see no play, forward or backward, where there had been before the rebuild. The driveshaft has a tight fitment at both ends with no typical slight sliding movement like it had before. The position of the transmission has not been altered and bolts in as it should. Any ideas?
 
Was the chatter during the engagement of the clutch, or driving with foot off the clutch and clutch engaged?
 
You need to figure out where the play for the driveshaft has gone before something gets damaged. That doesn't sound right.
 
Bought from a vendor I’ve trusted for decades for not only quality parts but great advice when prompted. They get their clutches from a builder they’ve dealt with for a long time. Note this disc is the second one I installed. The first, a few weeks ago, had a loose spline hub that took me close scrutiny to discover. This replacement disc (and pressure plate) looked fine, and the vendor sent without any hassle. I think we all understand parts are not always perfect in this old car hobby.
 
I think you’re on to the right focus here. The rear transmission mount is secure with the bolts fastening to the cross member as it should, which is why I’m so puzzled concerning the lack of play with the yoke into the output shaft. My next look-see into this aberration will be with the front motor mounts. Are they still good or have they failed? Thank you.
 
Bolt the clutch as if to install, then measure finger height.
I use the top of the clutch housing, straight edge and a depth gauge, could use a ruler
I'll bet they're different.

Karl
 
I would not worry about the clutch at the moment, but concentrate on the driveshaft.

Remove it at the axle and see how the yoke slides in and out of the trans. Study how far it can slide in.

Now refit the driveshaft and see where it sits.

If the driveshaft slides freely on the splines (before fitting) and when fitted sits further out than the furthest in you could get it (when not fitted). Then all should be good at that end.

If this all checks out then further investigations are called for.

You state it feels solid. How can that be?

Look at that first.

Mart.
 
Mart, I will do that procedure. Thanks for the words of wisdom. However, my huge oversight in my description of the yoke position was to note that I have all four wheels off the ground and the truck supported with jack stands. The position of the rear axle is placed slightly forward when the rear wheels are suspended. I discovered this while installing the rear u-joint to the differential yoke. For the u-joint to slip easily into the differential yoke, it was necessary to lift the differential with the floor jack. That action pushed the differential rearward enough to insert the driveshaft u-joint into position. Boy, ya learn something new every time you open up a can of worms, as this clutch replacement nightmare has proven. I appreciate your pointers, but I’m still focused on the clutch disc and maybe the pressure plate fingers out of adjustment with this new clutch package. I’ve done many clutch replacement jobs on various old cars, and never experienced this kind of clutch fail. Thanks again.
 
Ah ok, that would make sense. An easy one to eliminate early on.

Back to plan A then, clutch and fingers.
 
Just a silly question, you didnt use any new bolts , did you ? The pp takes shoulderd bolt but since this isn’t your first , Im sure you knew that . Just a thought . I’ve taken pp and converters off only to find vastly different size bolts .
 
Camac...not a silly question. If I remember right the pressure plate bolts are 1/4 with eighteen thread size and shouldered. I’ve reinstalled the original bolts but next time I will use new bolts; the length and shoulder look to be critical. Next step is to remove all clutch components and have the flywheel surfaced. I seem to recall that process involves balancing the clutch to the flywheel by the machine shop. This time around I’m going all out with doing this job as it should have been done in the first place. My initial inspection of the flywheel to my naked eye didn’t reveal any burn marks nor other odd anomalies. Looked as good as it did last time, prolly a few thousand miles back, but I’m now thinking this recent look-see was just more halfassed wishful thinking. I’ll let you know the results in a week or so after my machinist does his magic.
 
The bolts are 5/16"-18 with a relatively long shoulder and a relatively short thread.
 
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