adamkat22,

I just talked with a mechanic, good friend who owned a professional mechanic shop in Las Vegas and one in WA State (now retired) discussing your specific problem in detail including the filing teeth option.

He said that the ring gear itself on these heavier flex plates is replaceable without replacing the flex plate. It's not welded on and is removed with heat from a rosebud heating tip on an oxyacetylene gas (or other gas used) torch - the ring gear expands and comes off. It is installed the same way, heated to expand, tapped on in position and shrinks as cools. The tapered side of the gears of course must face the starter.

You could take your flex plate and new ring gear to a shop and they could do that for you (call for prices)

I ALSO found a Ford factory service bulletin from 1985 addressing the ring gear and starter in these diesels. You can read it in this thread:

Starter/Ring gear problems - Diesel Forum - TheDieselStop.com



His final conclusion: "Replace the ring gear, the Bendix gear in the starter and be done with it!" He said otherwise you'll be likely to have problems later on and screw up another Bendix gear and have to pull the transmission anyway.


He also said that replacing the Bendix gear in the straight line starters (not the gear reduction one) is very simple! Just buy the part (readily available) and he made it sound like replacing it could be done in less than 5 minutes, something about pulling a pin and putting the pin back in...

I have to agree with him- replace it and be done with it. That's my vote.

In the case of someone who can't afford the new parts/and work, filing the ring gear and replacing the Bendix gear is an option or possibly buying another starter from a parts truck on craigslist or a wrecking yard.

If I was stuck out in a very remote area I would hack the ring gear and the Bendix to make it work.

 

if i remember correctly the automatic has the ring gear welded to the flex plate.
the press fit ring gear is on the manual flywheel.

 

You should know Tom, That's what I thought too. My friend is in his 70's and has been out of the business since the 1980's and there was some confusion in discussing that detail, flywheel verses flex plate. He also said that if it has no welds then it should come off.

The discussion thread url I posted above where the Ford Service Bulletin is posted is interesting. As I recall it says that the Mitsubishi starter (gear reduction style) extends the Bendix gear further into the ring gear which can solve this sort of problem which some have suggested is not uncommon with these trucks.

I am tempted to change my starter to the gear reduction style before that happens! "An ounce of prevention saves a pound of cure" - or something like that.

 

I'll just quote here the relevant parts of the Service Bulletin, credit to the URL in that previous post:

Article No. 85-10-21

STARTER MOTOR - RING GEAR - EXCESSIVE WEAR - (6.9L)

LIGHT TRUCK 1983-85 E & F SERIES
CALIBRATION: 6.9L ONLY

Subject vehicles which have experienced repeated milling of the ring gear should have the existing starter motor replaced with the newly released starter (E5TZ- 11002-B), supplied by Mitsubishi, which has improved length of drive gear engagement. Simply replacing the drive gear on the existing starter motor will not cure the milling concern. Additionally, when installing the new starter, the ring gear must also be replaced (Part No. E3TZ-6384-A), in accordance with the instructions outlined in Section 22-08-30 of the (Volume B, Engine).

After replacing the starter assembly, two (2) nut/ washer assemblies will be required to secure the electrical cables to the starter motor assembly. (See parts list).

And this:

TIME: F Series Econoline
4x2 ................ T19 3.3 -
4x2 ................. C6 3.1 3.1
4x4 ................ T19 4.2 -
4x4 ................. C6 4.2 -
------------

By 'repeated milling' I'm sure that means when the starter gear has ground into the edges of the ring gear teeth, similar to how a milling machine bit would cut a slot.

The topic is about the ring gear on a manual transmission flywheel but the Service Bulletin is about both the T19 manual AND the C6 automatic transmissions in the F series and Econoline (E series) trucks.

So, adamkat22, This service bulletin from Oct. 21, 1985 applies to your van which means you need the new ring gear/flex plate, PLUS the updated model of starter, which was the Mitsubishi gear reduction style in order to remedy this problem and to assure that it probably won't happen again.

BY THE WAY, be sure to block that truck up very securely so it can't fall on you! I had a friend who I constantly warned about working under his Chevy 1/2 ton van using nothing more than a bumper jack and sure enough a few months later he was messing with the transmission and the truck fell off the jack and pinned him underneath until the fire department got there. No injuries, just pinned and couldn't get out

I warned another friend when he was checking wheel bearings on the front of a 1 ton GMC pick-up he bought back from me and sure enough a few weeks later on a highway in California he was messing with the same wheel bearing with only a bumper jack and the truck fell on his leg, causing some injury.

 

sorry i didn't get the 'notification email' that there had been so many responses.
i'm pretty interested in this idea of grinding/filing the teeth...but i'm not sure i understand the concept.

first...maybe i could get some clarification on some parts...

Bendix gear: is this the gear that I see in the starter when I put a new starter in?
Starter gear: same as the bendix gear?

i guess i just pictured that the gear i see in the starter engaged the ringer, and the reason i was having this problem was because the teeth of the ring gear were worn and therefore not engaging with the teeth of the starter's gear. if that is indeed what is going on, how would filing down teeth make them connect any better?

while 'precision' isn't exactly my strongest trait, it seems like i don't have much to lose, so i'd be interested to give this idea a try....

 

Not having a nickel, I can't really throw one in, or two bits for that matter. I have made a repair like this years ago, successfully, and see no reason it shouldn't be attempted. Because I'm a file guy, and possibly too patient sometimes (interpret that for yourself) I used a three corner file to put the bevel back on and clean up all the burrs. A dremel style tool would be fine too . Find a junk yard or lose flywheel/torque converter somewhere to view as an example, and reshape the teeth to suit. You need to have a good source of light, the vehicle needs to be up high enough to take the trans out even though you aren't, you still need that much room and if you're careful turning the ring gear from under the vehicle, levering against the bell housing and the teeth with a little pry bar works fine. Should only take a couple of hours tops. Good setup required, you don't need the vehicle falling off blocks, use rated axle stands.
Something else worth considering, additional to this repair, when a starter remains engaged with the engine running, it is in a huge overspeed situation. Upon starting it should disengage at low engine speed, so if it's held in it can be spinning at 2,5 or more times it's design speed, and has no limit to the current it draws in that situation. So, the starter gets very hot, windings fuse and short, and any part of its electrical supply system can too. I would check all the wiring and solenoids as a matter of course for signs of heat and repair or replace if necessary.

 

i guess i will choose between replacing the ring gear with a new one or trying the filing trick, but i need to learn more about what is involved with each option first.

can someone clarify what my goal is with the filing? i guess i'm confused on what sort of shape (which sides of the teeth etc) i'm trying to shape it to.

in terms of replacement...is anyone aware of a good picture tutorial or written step-by-step for dropping the transmission? or whatever else would be involved in this project? I've been searching but haven't had any luck.

 

Turn the engine so you see some "healty" teeth on the ring gear. You'll see (if I'm not mistaken....) the beveled edges of those teeth. Try to replicate that "shape" with the damaged teeth. The bevels help guide the teeth of the starter gear (aka bendix gear) to mesh with the ring gear teeth, rather than gnash against them.

 

so it doesn't matter that the teeth i file will get much thinner? its not that the bend is missing those teeth is just that its gnashing against them because they are the wrong shape?

 

You're on the right track here. The grinding has caused the teeth to wear and the taper that allows the starter Bendix gear to mesh with the ring has disappeared as the tooth has worn back. Take all the burrs of the teeth and reinstate the taper, replace the Bendix, should last you a while. The starter Bendix throws forward quite a way so engagement shouldn't be a problem.

 

ok. i will look at it again tomorrow and see how it feels to approach that.
if i decide to replace the whole thing is anyone aware of any good tutorials/videos/pics on doing this job. i have a manual but it really isn't that helpful because it basically goes through the whole job in 10 steps...and in each of those steps are a dozen parts that i don't know how to locate..

 

EXCELLENT POST by southern-old-bold!!! go over that one well adamkat22.

Original ring gear is case hardened steel = it's harder at the surface than the metal inside. You should not have to worry about filing it too thin because you will only be filing the metal that has been squished outside of the original lines of the original (new) gear. In this situation these can be called burrs and they have to be removed with a good metal file or grinding tool. You won't be filing any metal off of the good part of the gear that does not have metal squished out.

Look at this flywheel ring gear. It is from an MG sports car. It's not as damaged as yours but look closely and you will see burrs = where the metal has been pushed out on the edges beyond where the edges would be on new gears.
http://www.mgexp.com/phile/1/202007/...thTopview2.JPG


THESE burrs have to be filed off so what REMAINS of the gear after the burrs are removed is the closest to the shape of the original new gear, minus the metal that has already been chipped off of yours and is no longer there.

What remains of the gear teeth after filing needs to be the same shape as as it would be in a new gear. There is not much metal that has chipped off of your ring gears so there will be plenty gear left for the starter gear to mesh into and turn the ring gear. The NEW STARTER gear should slide into the ring gears to a depth of at least 1/2 one to 2/3 of the distance into those ring gears. It might not be able to do that when burrs are in the way so when the starter gear can't slide in, it will spin and grind on the edge of those ring gear teeth like a very large drill bit and damage the starter gear and the ring gears.

You can see on yours that the starter gear did not go 1/2-2/3 into the ring gear before it started to grind and it ground off the ring gears and the starter gear. This can happen when starter bolts come loose because they were not tightended to the specified torques (not tight enough) or when old starter bolts are used that don't hold tight. USE NEW STARTER BOLTS

AND:
According to the Service Bulletin THIS was a problem with your van and other 6.9L diesel trucks manufactured up until 1985. The remedy was to replace the starter with the Mitsubishi style starter which engages the starter gear deeper into the ring gear and substantially prevents this problem - and of course replacing the damaged ring gear and that is the BEST repair.

In your case we are considering filing the burrs off of your ring gear to avoid the replacement work. The damage is not very bad on yours so yes this will probably work if you can clean up those damaged gears with a file.

In my opinion you wont have to file much at all on the middle part of each damaged gear that faces the starter where the metal has been chipped off, just lightly smooth off any jagged metal edges in that area (any other opinions on that? But it's a good idea to file a small bevel on the side edges of the gears to help guide the starter gear into the ring gear. Look at an undamaged tooth edge to see the side of the bevel also on the very tap edge of the gear.

The starter gear already has bigger bevels.

ALSO there is a little bit of metal at the bottom edge of the damage on some gears that is protruding past the face of the ring below the gears and that should be filed off. Everything that is protruding past the edges of what a new ring gear would be needs to be removed with a file.

Not everything in the world has been scanned, photographed, filmed and digitized to put in the Web, very very far from it. I spent 3 hours looking at hundreds and hundreds of photos, videos and information from various sources to help you to visualize this process and I've been an internet addict for 17 years spending 16-18 hrs on the web every day (during a disability period) and I am very skilled at searching out information. I could not come up with what I thought would clearly illustrate this procedure in steel gears fo you.

ONE trick to remember in searching is to use different related and applicable terms (or words) in your search query. if you don't find what you need, change the search terms. Sometimes on very difficult to find information you can find a back door to it by using terms not directly related to the problem but indirectly related. I use various search engines for different things and never search from pages like Yahoo or MSN or whatever your ISP presents to you- I never use add-on search bars. Actually I rarely use google but search engines that scan google but searching directly from the SSL Goggle searh page is a good place to start: https://www.google.com/ it's a secure connection to google search.

Otherwise you can improve your search abilities by looking up how to improve your searches.

BY THE WAY, this would ALL be simple if I or anyone else who understands this or someone local to you could just show you in person.

I think you need to decide what you are going to do, replace or repair, and then get get started. As stated, a repair manual from a parts store will tell you step by step how to remove and reinstall the transmission, the flexplate, the starter, etc., etc.

Also curious if you are you in a small city in NY or a big one? Out in a rural area? and one thing that I have been wondering is what do you use this very cool F350 Van for? Is it equipped any special way for work use or recreational use? Either way I would probably use it for camping and when I need to haul some heavy stuff but I have my pickup for that.
I think I would be doing camping trips

 

I didn't find any videos or specific detailed instructions/photos on removing a C6 from a diesel or from a gas engine for that matter. Automatic transmissions in trucks and vans of that general vintage are quite similar so maybe you can find a video.

Parts you don't know how to locate? LOOK THEM UP in a search on google for example and click on IMAGES hyperlink to the top and Right of the page for images or video link for videos.

https://www.google.com/ add that url to your 'Favorites bar' (if using windows) for quick access if you don't have it already.

Most of us don't have the time to be full time automotive repair instructors on these forums.

 

ah ok i was confused as to what i was supposed to be beveling. just to confirm..i should just bevel the tooth faces that i have shaded pink in the attached photo correct and not worry about the face that i have shade blue...

i just need to remove the burrs that have bled into the "v" shaped area in between teeth..now i understand what you all were saying.

i'll give that a try

 

When the starter Bendix is not engaged,it is parked outside the blue pointer.(near to the camera POV) As it engages,it moves through the zone of the blue pointer you have placed to show the blunt end of damaged teeth on the ring gear. As it engages it moves into the parallel 'pink' zone and rotates.
Ok. The starter Bendix is crashing into the blunt end (blue pointer) and not meshing in the parallel pink zone. Take the burrs off the blue zone all round and then put about a 30 degree beck on the driving corner near the blue pointer. This reduces the width of the end of the tooth and make a ramp for the state Bendix gear to climb in on. Maybe you haven't found another ring gear to look at, and I am not tech enough to post a photo of mine which I actually have the cover off. Can someone else oblige with a PIC of the bevel please, 1000 words will get there otherwise!