No 3rd/4th

[DiscoJen]

Alright, after finding that the old synchro was destroyed, I put a new one in this morning. Finally!

New synchro slides forward just lovely...until the bellhousing is in place and fully seated. As soon as the bellhousing is on, the synchro will barely move. I can spin the shafts freely and the gears rotate as I would expect them to based on my little understanding and experience. But that synchro just sits there like the lump of brass that it is.

Take the bellhousing off and it moves forward again as expected.

What the heck would still be causing my synchro to not move??? :banghead:

 

[JackW]

The synchro has to go on a particular way - refer to the shop manual and you'll see that the end of the synchro with the thicker teeth and the recessed splines on the inside have to go toward third speed gear - toward the rear of the gearbox. Try that and see if that works. If the teeth don't match up it won't move

 

[DiscoJen]

I totally skipped that page in the Green Bible and didn't even notice that the ends of the synchro are different. But I just got back in from checking and by pure luck I had it in correctly. Distance piece and constant gear are in proper position as well.

Grrrr, gonna tinker a bit more...

 

[JackW]

You do realize that only the center section of the synchro actually moves forward - right? The big disc in the middle of the synchro that the shift fork engages slides forward or back within the "cage" of the rest of the synchro which moves the toothed piece in the hub of the synchro into engagement with the small teeth near the hub of 3rd or 4th gear. What the synchro is doing is locking the gear to the shaft. Sometimes the flat springs are a bit stiff and its hard to overcome the initial centering action by hand. Also the other gears should be in the neutral position. I'm hope you know I'm not trying to overly state the obvious - I know this is your first dive into a gearbox and I'm just trying to help.

Maybe a picture would help - looking down into the gearbox with the top cover off. Lots of us are intimately familiar with that view of a Series gearbox and we might spot something.

 

[DiscoJen]

Thanks for all of your help Jack. I'm wondering if I am understanding the operation of the synchro incorrectly. It is wedged firmly between the primary pinion and the 3rd gear. And the 3rd gear assembly does not slide at all. I assumed that the entire synchro assembly would move back and forth easily like how the other synchronizer ring and the reverse gears slide along their shafts.

I'll try to get some video of the installation of the synchro and how everything is operating to post up. Raining today so it may take a few days.

Good thing I'm as stubborn as this gearbox is.

 

[JackW]

If you've got the Green Bible just be sure to study gearbox operations drawings near the front of the gearbox section. Figure C1-17 shows the power flow with top gear engaged - high ratio, two wheel drive. Notice how the synchronizer looks in that drawing with the center ring shifted forward to lock fourth gear to the mainshaft.

Second, Third and Fourth gears on the mainshaft don't move back and forth - they just spin freely until the hub of the synchro slides over and engages the splines inside the main gear and locks it to the shaft. The first gear moves back and forth on the main shaft but all of the other gears are fixed.

 

[DiscoJen]

I could hug you Jack! When I looked at those diagrams I didn't even notice the slight change in C1-17 showing the center plate of the synchro moved. I was only looking at all the bold arrows. It's so weird, cause I even tried to move the center plate on my old synchro (with springs removed) and couldn't get it to move and ruled that out.

I also just tried to move the new synchro by hand and no luck, but it's pretty tight in there like you mentioned. I'm gonna put the forks in and cover plate on in a few days and see if that gives me the leverage to select 3rd & 4th. Even if it doesn't work I have at least learned how the synchro works - finally.

I'll update again soon and cross your fingers for good news!

 

[JackW]

You can just position the first and reverse gear sets properly and put in the third/fourth fork and try to actuate the synchro while you slowly rotate the input shaft. Make sure you have some kind of lubrication (like LPS) and you can probably get the thing to slide back and forth with a little gentle persuasion. It sounds like you're becoming enlightened on Series gearboxes - you'll be an expert in no time.

 

[DiscoJen]

I finally was able to push the center of the synchro!!!! At least outside of the gearbox anyways. Putting it all back together and got the bellhousing on. The Bible says to tighten the layshaft nut to 75lbs. Seriously? I don't even have a socket that size and I was able to loosen it with a pair of pliers once I got the cotter pin out.

I guess if it says 75lbs then that is what I"ll give it.

Then I"ll put the forks and top cover back on and see if I can shift.

I'm assuming that if I can select all gears when the box is outside of the truck, then once it's bolted it should do the same. My biggest fear is of getting it back in and then realizing it's still not right. At that point I am liable to throw the thing up on CL and not look back. It's starting to beat me down. I"ll probably feel better tomorrow cause the temps will drop a bit; its HOT here already.

 

[DiscoJen]

a happy update!

By george, I think I got it!!!

Put the top cover and gear shifter in place last night, and after a bit of tugging I've got the synchro innards moving into 4th. 3rd didn't seem to be moving as far forward as I would have expected. But a little more tugging and I think it's hitting 3rd now.

I took some video that I'll post tonight so that ya'll can check it and see if I'm getting even forward and aft movement before buttoning everything up and reinstalling the heavy lump.

I think I'm gonna go ahead and install breather fitting in the top plates while I've still got it apart.

I feel good!

 

[DiscoJen]

Alright, here is some video showing how much movement I am getting going between 3rd and 4th. It loosened up after a few tries and felt like it was hitting 3rd much better. Does this seem about right?

http://www.youtube.com/watch?v=YoKpKorhvig

 

[JackW]

That last couple of clicks looks about right - you should be turning the input shaft while you shift the lever back and forth - that way the little teeth on the synchro have a chance to engage and everything can line up and slip into full contact. Notice how it wasn't engaging third at first and then something inside the gearbox rotated so it could slip all the way in....I think you've got it - now you just have to get the other two shift forks in and button it up.

 

[DiscoJen]

The gearbox is back in the truck and a mere inch away from hitting home. I just can't seem to get the studs lined up enough to slide forward by myself. I got tired of waiting for a helper, couldn't find a small enough engine hoist that I could handle by myself, so I ended up using a couple of 2x4's, bottle jack, scissor jack, and a ratchet strap and actually pulled the thing up from under the truck. That was tricky as hell, but damn did it work. In less than 3 hours at that.

I'll wait for a helper tomorrow that is stronger and taller to stand on the frame and wiggle it the rest of the way in place.

If I wasn't so damn sore everywhere I'd feel great. Ahhh heck, who am I kidding, I DO feel GREAT!

 

[apg]

OK - here's how to do it....

Buy two 5 to 6" long bolts the same thread pattern as the bellhousing. Cut off the heads. Thread these into opposite holes on the bellhousing, then as the Green Bible sez, "offer the gearbox to the engine." Mind you, you don't want to hang the gearbox's weight on these two bolts, they merely act as parallel rails to guide the box home. For extra credit, cut a screwdriver slot in the cut face of the bolt to aid in removal.

Now you may find that the gearbox hangs up 1" of so from going home. It's the splines on the input shaft not engaging in the flywheel.... If you are working by yourself, put a little pressure on the back of the box with a hydraulic jack on its side. Then walk around to the front and give the engine a bit of a turn with the hand crank. Sha-zam...box slides into place. Done.

Then go have a cold one in the shade.

Cheers

 

[DiscoJen]

So happy that this evening cooled down a bit. With a little help lining things up, various placements of 3 sets of jacks, finally pushed everything home. The gearbox is bolted to the engine and I'll fiddle with the other bits over the next few days to see if the ole fella drives.

And I definately just got back from enjoying a BLT and a beer. :drool:

 

[JAKD-UP]

call me if you need me to come over and help ya

 

[DiscoJen]

Ran into a new problem. When I bought new trans mounts they were almost double the diameter of the old ones. I didn't think at the time that it would matter.

Now here is what I am running into. http://s233.photobucket.com/albums/ee284/sailorjennie6/?action=view&current=PICT0110.jpg I can line up the mounts on the passenger side, then when I go over to line up the drivers side they are about an inch off.

Would the larger diameter on the trans mounts cause this to happen? I'm pretty sure I have the left and right trans mount brackets on the correct sides.

 

[ca_surveyor]

I ran into a similiar problem on my exMOD. The previous or his/her previous owner had switched the mounting brackets, which caused the driveshaft to be way off center. Corrected that after replacing the motor mounts and all looks pretty happy now. Happy hunting.

 

[DiscoJen]

Well if this problem isn't annoying enough, I thought I'd go check out the clutch. Pedal hard as a rock and won't even budge.

Anyone want to buy a Series?!?!?!?!?!?!!??! :banghead: :banghead: :banghead:

 

[apg]

OK....let's sort through this.... Whenever the clutch is out of the protection of the bellhousing, it can seize or rust up, but that wouldn't result in a hard pedal. What would cause it is internal damage to the clutch's flex line. This is situated so that is is hard to see, let alone replace. So it rarely gets replaced - and it's in a hot, oily area of the vehicle. Yours could be four decades old.

The hose might look fine on the outside, but if the rubber degrades internally, it will function like a one-way valve. The clutch "pumps up" but the 'valve' doesn't let pressure return to the master cylinder.

Crack the connection at the slave first. Just press the pedal...you don't want to suck air back into the system. Retighten. Observe the fluid level - and while we're at it the color of the fluid. Black or dark with tiny bits? Or clear? Press the pedal several times - if the level goes down and the pedal gets progressively harder, you've found the culprit - the flex line.

It's way cheaper than another vehicle.

Good luck