Transmission Advice Please

[kwmech]

Cannot really tell from the pic, but...looks like the pilot bushing is not in deep enough. Also, did you put any grease inside the pilot bushing hole?

[Richard2112]

Originally Posted by Captainfab

Yes that disc is correct. So what else did you change besides the clutch disc, TOB and the trans? Is there more than one location to connect the clutch rods on the bellcrank?

We might be on the right track here. This hadn't ocurred to be but I did change the crossover and mounts to the bellhousing....hmmmm...

My original crossover was riveted in and it was quite beat up. Also, someone had cut away a portion of the crossover flange (for what reason, I don't know) on the passenger side with oxy acetylene. Perhaps for clearance for a pto, just a guess.

When I pulled the trans I took the opportunity to change the crossover. I read in a thread here (which I can't seem to find now) that the crossover with slots was for an inline 6 and the crossover with holes was for the V-8.

My old crossover had slots even though there is a 350 engine. I know from the block casting numbers that the engine is a '77 but my truck is '69/70. So the motor, though old, isn't the original and there may have been a 6 cyl at one time.

I cut the old crossover out and replaced it with the one shown after replacing the rivets with grade 5 bolts. I got the crossover from a seller on fleabay and it was listed as coming from a c-20. It fit but it was (as expected) a fight to get it in place. Ultimately I had to use the bolts to draw it into place. Once it was in place, the bellhousing bolt holes lined up nicely and I loosened the fresh crossover and installed new mounts.

The new mounts and the crossover picked up the engine and trans a bit. I know this because I had the engine resting firmly on a jack stand. But after bolting in the new crossover and mounts, the engine was up off the jackstand maybe an inch. I figured the old crossmember had sagged and the mounts had worn, never giving it further consideration.

There is only one location for the clutch rods on the bell crank but I did make new nylon bushings for the bell crank and re-installed it. The problem I am having existed before I put bushings in the bellcrank and it remained afterwards also. Just the bellcrank isn't sloppy anymore.

Old crossover/mounts.....new crossover w/holes

[Richard2112]

Originally Posted by kwmech

Cannot really tell from the pic, but...looks like the pilot bushing is not in deep enough. Also, did you put any grease inside the pilot bushing hole?

The pilot was set in flush with the crank and before I installed it, I let is soak in 30 wt oil while I was doing other things. I soaked it for about ten days but no, I did not grease it.

Interesting though is that the old pilot wasn't seated in flush. This (bad) photo shows a ring where the old bushing was sticking out.

[Bigdav160]

A little late but I have seen several pilot bushings that were too tight on the input shaft. Sometimes only after installation. Off shore production? IDK.
Anyway, I would check it carefully.

[Richard2112]

Originally Posted by Bigdav160

A little late but I have seen several pilot bushings that were too tight on the input shaft. Sometimes only after installation. Off shore production? IDK.
Anyway, I would check it carefully.

If that is the case, would it show when the alignment tool is inserted?

I don't know if the alignment tools are constructed accurately enough to reflect a change in inner diameter of the bushing after install. Maybe they are but I do not have the experience to know.

My alignment tool fit well, not overly tight but I don't know if that can be used as a good metric to determine if the bushing ID has changed.

I wonder if the bushing ID has indeed changed, is this a circumstance wherein it my have to go through a "break-in" period to allow the new part to set?

[Captainfab]

IMO, if the pilot bushing was the culprit, the issue of the trans internals turning would not change with how far the clutch pedal is depressed.

[Richard2112]

Originally Posted by Captainfab

IMO, if the pilot bushing was the culprit, the issue of the trans internals turning would not change with how far the clutch pedal is depressed.

I agree. Although at first glance, the symptoms would initially point to the pilot bushing, further test sorta rule that out.

This is what I think is going on:
The lift from the new crossover and mounts brought the pivot points of the linkage closer together averaging out to a longer throw at the fork. This probably wouldn't normally happen if the linkage rods (which I assume served an original I-6 bell crank) had been changed when the motor and bell crank were changed to V-8 style.

Since I can't compare linkage rod lengths, this is all just an assumption but as long as I restrict the pedal travel, everything seems to work properly.

I may drill another hole in the bellcrank to adjust the geometry or fab a threaded rod which is adjustable. In any case, I believe the cause has been narrowed down to the linkage geometry.

I want to thank every person who contributed to this thread as every single idea has been taken into consideration and it has been the combined effort of all who shared ideas that helped bring about the solution.

Hopefully others will find this thread as helpful as I have. Much thanks.

Now on to get my driveshafts cut and installed...