Hey guys, I have this little problem... just about every time i put the truck in reverse, it doesn't seem to go into gear all the way, and as soon as i let out on the clutch it grinds and pops out. I'm kinda thinking maybe the shift forks are bent or theres a linkage problem, but reverse is the only gear i have problems with. It also seems that if I put it in reverse before i start it, it happens less. If I sit there and play with it, it works, and once it gets into reverse, it stays there, doesn't pop out or anything while im moving. Any ideas where to start?

 

Syncros for reverse are wore out, or as you stated the shifting fork for reverse is bent. Unfortunatly a rebuild is the only cure.

 

that's what i was afraid of... well, I guess i'll just keep goin the way it is until i get the money to fix it or it quits on me completely, whichever comes first... these zf's are quite a bit tougher than the e40d, but when they go... thanks man!

 

My truck has had the 3rd synchro going out since I bought it. Gotta learn to double clutch lol.

Reverse would of course be a bit trickier. What is your push rod eye-let like?

 

Popping out of gears is typically worn bearings

 

Have you tried going from 4th to reverse? Mine sometimes does a half engagement of reverse if I go straight into it.

 

out of curiosity how many miles are on the transmission? I agree with brad sounds like a bearing problem if your trying to shift in at dead stop and it wants to jump out

 

Mine was doing that and syncos and new shift collars fixed it

 

The trans has 150k on it. It doesn't pop out of gear once it engages, it just pops out when it grinds, like its only halfway in almost.

 

it could just be something bad/bent in the pedals/hydraulics/clutch fork/clutch setup that's not backing the clutch completely off of the pressure plate. i had a similar problem with a truck of mine at 220k and a new clutch fixed it right quick. turns out, the finger springs on the old clutch were completely shot so that it wasn't disengaging evenly and completely.

how new is your clutch? if its original at 150k mi, a new one is probably due anyway - and is much cheaper/easier than a rebuilt tranny.

plus, if it goes into gear fine with the engine off, its probably not bad transmission internals as, if it was, the problem shoudl occur whether the engine/flywheel is spinning or not.

on a related note - do these transmissions have synchros on the reverse gear? you don't ever want to go from forward to reverse without coming to a [near] full stop, so there'd be no need for a synchro. i know most manual transmissions don't have reverse synrchro's anyway...

 

x2 that a not fully disengaging clutch -can- cause this. No kidding.

But so can the other things mentioned, and mine has trouble from all of 'em. :)
The slave leaks down and having-more-trouble-than-usual with reverse is the
first symptom. Trouble with second and 3rd is next.

I've got new bearings and new gears (2nd 3rd rev) with complete synchro hubs
ready to install in the Bronco but the wife is driving it too dangged much! LOL :)
(gotta get her little Mercury Tracer going soon! ;)

All the Ford/ZF's I've heard of are synchronized in all gears, including reverse.

Alvin in AZ

 

I skipped posts because you guys immediately got into syncro's right off the bat.

Let me go over a few things here.

The shift linkage from the shifter to the trans is a ball socket connection on our trucks.
They do not mate very tightly, thus sometimes there are issues with getting it into gear like you are expereincing.
I had this issue when I first got my truck.

The Heim Joint fix was one of the first things I did and that eliminated 90% of my issues because it was clutch related.

Okay, so what I found out was my 2nd gear syncro's were toast.
Reverse was still hard, but I found out if I snapped it into gear as opposed to pushing it into gear, it went in. Weird huh?

Why is that. Think of something thats sitting on a table, if you push it, it goes as far as you push it, if you tap it with lets say a hammer, it pops forward right?

Same thing.

what happens is not that the syncro's are bad, but the shift tower cannot push the selector into gear well enough to get the full engage.

Okay, you can say thats a syncro issue all you want, but it isn't always the case.

How do I know this?
when I put in my short throw shift kit and it changed the falcrum point on my shifter and allowed me to apply more leverage and move the shift selector further, I have never had an issue putting it into reverse unless I physically didn't pull the shifter into place.

Syncro's are not going to cause you grief while stopped getting it into gear.
Syncro's are so you can get it into gear while the transmission is spun up and the drive shaft is turning.
So if your rolling forward and want to go into reverse and it grinds...

if your trying to put it into reverse and it wont go while your stopped, its cause your clutch isn't dissengaging and the trans is spinning, or your not getting the selector far enough in.

 

Yeah, but. ;)

I've got a ZF (351w) in my Bronco from a '90 F250 ^8500# pickup and
I used some hard+ground steel washers to take up the play inside its
shifter, I bet it's tighter than new... ;)


Next:
"synchro" means more than just the tapered ring. It's a whole assembly
that -includes-the-gear-too- since the little pointy teeth the synchro sleeve
slips over, is attached to the gear and those little pointy teeth need to be
the right shape. There's where the trouble -could- be with a shifter not
being able to get it into gear while it's stopped also.

^That there? :)
It's mentioned in the ZF manual. ;)
I'm not smart enough to make this stuff up. LOL :)

The little teeth attached to the gears are mostly hidden here by the large
diameter synchro sleeves, the sleeves have got the square groove all the
way around for the shift forks to fit in...

The upper synchro sleeve is for 1st and 2nd. Too bad 2nd gear is laying
there face down or you could see its attached-little-pointy-teeth. :) The
lower synchro sleeve is for 5th and reverse. Reverse gear is the gear
there in the middle with its teeth slanted the opposite direction from the
rest of the gears.

Those are the "driven" gears that's why 5th is so small and 1st is large. :)

3rd gear isn't shown, and there really isn't a "4th gear" because it's just
little pointy synchro teeth on the input shaft and 3rd+4th's synchronizer
body on the main shaft.

Here's the "drive" gears mounted on what Ford calls the "counter shaft"
but also called a "cluster gear", it's there just below the input shaft. And
that's 1st gear's "drive gear", ground right into the shaft itself... :)

The tapered/conical part the synchro ring that slides onto (and works at
locking itself to it too) can be seen there at the end of the input shaft.

That's basically 4th gear! :)

In between those two is the 3rd/4th synchronizer "body" or "hub". That's
included when you buy a complete "synchronizer" along with the sleeve
and the rings. :) And also happens to be part of "4th gear" too. And that
synchro body fits the splines on the top of the second picture. Get it? :)

Alvin in AZ

 

man - that's some good info there!

my favorite part is the BFH there in the first image. that's just shown for scale, right? ;-)

seeing only that one special tube of a square tube with the threaded rods - a puller of some sort, i'm guessing - makes me thing i could rebuild mine if i ever have to... i'm sure there's more involved than is shown in those few images, though.

reading the ZF rebuild manual is pretty daunting what with their list of special alignment tools and such needed.

crazy that 1st gear is ground into the shaft. not sure i see how 4th gear works, but i guess i don't need to [just yet].

 

Cool, thanks. :)
That BFH was a little 8# sledge hammer with a broken handle I bought
at a secondhand store for $2 and made a "single jack" out of the parts. :)

I really like that sucker, it can cut-off frame-rivets other hammers can't.
No kidding, "little taps" work harden the rivet quick as anything then the
chisel stops cutting, the rivet starts dulling the chisel. With that 8# I can
hit 'em hard enough the chisel never dulls and the rivets heads just keep
peeling up and go flying. :)

Nope, not just for size... xD


Not a very good picture of "the square tube" because it's two curved leaf
springs facing each other. I made do with what I had was all. :)


That thing is so full of crap it ain't funny. No really, it ain't funny. ;)

There's a thread on FTE somewhere that's got my procedure in it, tells
where I learned it from a guy all the transmission shop owners in town
called "-the- ZF guy in Tucson".

"-the- ZF in Tucson" said...
"who can afford all that tooling? :)"
"you don't need it anyway"

The book wants all sorts of fixtures to hold things too. :/
I made a ZF stand using an old 5 lug aircooled VW wheel and just bolted
on a hunk of iron the ZF could be bolted to.

"to get a ZF apart I just slam it down on the concrete floor, you know,
with a hunk of carpet to protect the end a little bit"
"rap a rag around it to contain the pieces that fall off"
-the- ZF guy

Here's my picture...

...the delicate;)procedure ruins this special-made-ZF-part that you can
replace with an off-the-shelf retainer ring... (little ring is for show)


Yeah to save space and IMO it's still not low enough, 1st is too high in
the ZF. Maybe it'll be ok after I swap my axle gearing from 3.55 to
3.73 or 3.90? Only have 32" tires at the most.

4th gear is 1:1 so it don't have a single "gear", just lock the input shaft
to the "main" shaft and you're in 4th gear. :)

Finished, fun's over... :/


Alvin in AZ