As the classic song goes, "So close, but so far away…" is the story of installing my 4 speed transmission back into my 69 350/350.

Lined up the disc with the plastic alignment toy, purchased 4'' bolts to guide transmission, and had my daughter push the clutch in. Slid in well except for the final 5/16". Already checked the pilot bushing for fit.

Suggestions and other tips are welcomed!

A view from the bottom--the bolts are not tightened.



A view in between frame and exhaust pipe to show gap against the top guide bolt.

 

Just keep shaking. Looks like it's in the disc OK, just needs to get into the pilot bearing. Get the gaps as close as you can and it should slide on in.

 

Ok, I've pushed and twisted with the chutzpah that would make Flex Crunch proud and the gap is now 3/16". Besides the pilot bushing, what else could be hanging up the transmission?

 

DO NOT TIGHTEN WITH THE BOLTS TO DRAW IT IN, YOU WILL SNAP THE EARS OFF THE TRANS.

That said, set up the clutch linkage and have someone press the clutch pedal, once the disc is released (clutch pedal held in), the trans should slide the rest of the way in with minimal effort (relatively, anyway)... Make sure that the clutch disc is fully released...If the linkage is a bit loos, lengthen the bottom rod for the time being...

Also, install the yoke in the back of the trans, and put the trans in 1st or reverse..working the yoke a bit might also help is get a slightly better slid through the disc into the pilot bushing...

Those plastic tools get it close, but not perfect...

 

I can relate to this. In my case, I mushroomed the pilot bushing slightly installing it. So after this "close but no cigar" routine a few times, I pulled out the trans, miked the tip of the 4sp and then miked the inside of the bronze pilot bearing and found the bushing was a few thousands smaller than the trans tip. Opened up the bushing a few thousands and it finally slide in. This may or may not be your problem, but hope this might help.

Even after I cleaned up the pilot bushing id, I still had to wiggle the 4sp and get the wife to push clutch in and out to finally get it to mate up.

 

Try cranking the engine over with the starter. T

 

Did you slide the pilot bushing over the input shaft before installing the pilot bushing? How tight was the bushing in the crank? If too tight the ID will change. As another post mentioned he had to open up the pilot bushing.

You cannot force it in to place. I did use the bolts to pull in the trans the last 1/4" but there was NO resistance.

Did you change the pilot bushing? If not, than it is just an alignment issue. The alignment tool is such that all the parts should be aligned including pilot bushing. Did you make sure the alignment tool was pushed all the way in to engage the bushing?

Bill

 

I had the exact problem with my 69 350/350. When I reinstalled the input shaft cover, I just tightened the bolts but did not pay attention the their orientation. I pulled the Muncie out and examined everything. Turns out the that the bolt heads the input shaft cover were the culprit.

Make sure the bolt heads do not protrude over the outside edge. Sound simple but it was enough to stop the Muncie from going in. Reinstalled the tranny after adjusting the bolt heads. Viola! Done

 

It's been my experience that the plastic installation tools are too loose and won't properly center the clutch plate.

I do use the tool to hold the clutch plate in place and then check the alignment at the edge of the clutch plate and flywheel and correct it when the clutch bolts are just finger tight.

 

CF members, I appreciate all of the contributions. My hunch, after reading through the replies, is the issue lies with the pilot bushing. Either the end was mushroomed or the inside diameter shrunk after installation.

If I discover the pilot bushing needs resizing, it is better to install a new one or is it ok to file and reshape as necessary?

 

my experience, I miked the od of the 4sp tip and then dug around until I found a round piece of metal that was a couple of thousands over. I tapped this new piece of metal in and spun it around until I got a clean fit. A friend told me that they actually make a tool to tap these in without mushrooming but of course I did not have that tool. I think I also, filed a slight chamfer on the entry of the pilot bushing. IMHO this is not a precision bearing, but a chunk of bronze bearing material, and I think the only time it is doing anything is when you push the clutch in.

I suggest you mike the od of the 4sp tip and your installed pilot bushing and see if you think you have an interference fit.

Hope this helps. BTW, my 4sp works fine after all of this, so that is one data point anyway, ha!

 

After pulling the pilot bushing, I believe the cause is clearly illustrated from the darker bands captured in the comparison pics. Because the bushing was not installed correctly, that is uniformly seated, it ended up snagging the input shaft. A deep groove/gash visible on the inside.

While poking around the Team Chevelle site, the consensus opinion on pilot bushings is not to commit assumicide and think that a bushing right out of the box is ready to install. Take careful measurements and possibly account for the pressure of installation squeezing the inside diameter. One suggestion is to freeze the bushing before installation.

It's is my $10 lesson for the day and maybe it can help someone else.

Note the thickness of the darker colored band, it is about 1mm wider than the band showing on the opposite side of the bushing.



I've ordered a new bushing, hence my $10 lesson.

 

Any auto parts store should have that in stock.

 

I looked all over even listened to The guy at Napa say the roller bearing was better. I found the Bronze National part at Orielys. because the guy said their was a old one on the shelf in the back.

 

Make sure the bushing is not magnetic. A lot of the aftermarket bushings are magnetic. The original bushing were not magnetic.

Best available bushings come from Autogear. Pure Oilite bronze and non-magnetic.



Bill

 

When I installed my clutch and mocked up the trans, it wouldn't slide in either. It ended up being the plastic clutch alignment tool having too much play. I bought this fancy tool from Ram clutches, re-aligned the discs, and the trans slid right in. I used input shaft would do the same thing, but they can be hard to find. I agree with the poster above, the AutoGear bushing is the one you want.

 

My experience with using the bolts to draw in the trannie is that the bolts will strip the threads in the bellhousing. My experience. Anymore, I have the bolt holes in the bellhousing replaced with steel insert threads. I've had to do this with one bellhousing, and just for caution have had inserts added to the second bellhousing. I don't do the inserts my self. I take the bellhousings to a machine shop that does only broken bolt removal and tread repair. (Jerry's Tap and Die in Santa Anna, Ca) With a specialty machine shop, the inserts will be installed dimensionally accurately.

I don't use those plastic ******. I have course spline and fine spline Muncie input shafts. They are so much more accurate than the plastic ******.

Good comment about the pilot bushing being distorted by installation.

........I'm not really that good of a mechanic. If I personally had to replace a tranny. I'd just remove the entire engine/trannie stack and replace the tranny outside the car. I've pulled out an entire engine trannie stack from a Corvette three times, and re-installed two times. For a early C3 Corvette it's mechanically very easy to pull the entire engine/tranny stack....it is very tedious however. At my proficiency level, replacing a trannie laying under the car is not going to work. (Even though I have a trannie jack). With an open frame, and the trannie jack, I found installing my TKO600 into a dual disk McLoed clutch to be very fussy. The dual disk requires that the input shaft be inserted more accurately than with a single disk. Absolutely no way could I do this laying under the car, especially with the welded in tranny crossmember that manual C3's had.

 

Following up… I purchased a Federal brand bronze bushing and left it overnight in the deep freezer. The next evening, I removed it from the freezer and was able to slide it over the input shaft.
The bushing was then pounded into the flywheel center and the effort was noticeably easier than the previous attempt using the bushing's room-temperature cousin.

I let the bushing set for awhile believing it would undergo thermal expansion and accept the input shaft. It did not go. The plastic alignment toy fit, but not the input shaft. The bushing's inner diameter had compressed. I mic'd the shaft and the plastic alignment toy tip and noticed 6-8 thousandths difference. After checking the measurements again, it still showed 6-8 thousandths difference.
Modeling the most uniform circular motion possible by human hands, I proceeded to enlarge the bushing's inner diameter with my drill motor and 1/2" drill bit. Cleaned up the debris. On the next attempt, the input shaft slid through the bushing. Success!

Tomorrow, I'll keep my fingers crossed and hope to mate the transmission to the bell housing.

CF members, thank you for all the help.

Transmission input shaft diameter


Plastic alignment toy tip diameter

 

Off to a great start this AM. After all the learning and redoing, I was blessed with the transmission sliding in place with minimal effort.

 

Congrats on getting it installed. You should not have had to hone the bushing. Did you slide the bushing over the trans input shaft at room temp before installing the bushing into the crank?