I have a 1984 F250 w/ 6.9l idi and a 4-speed manual which would be a t19? Correct me if wrong. And it seems i have a bent shift fork, i can't find the 1-2 gear shift fork anywhere! Any body know where i should look?

 

The shift fork that pulls the clutch off the flywheel? Should be at a ford dealer, eBay or LMC.

 

I think thats a clutch arm or fork. I need the fork that grabs for 1st and 2nd gears because im starting to loose 2nd.

 

Have you pulled the boot in the cab to see what's going on? Mine rattled the large nut loose and eventually the pin popped out and I lost all gears.

 

Pull the transmission hump/cover off the floor of your truck and then removed the shift tower and inspect. I doubt your problem is in the shifting forks, but rather the gears of the transmission itself.

When a fork jumps the collar it rides in it doesn't usually go back in place on its own, you have to pull the shift tower, manually place the gears in neutral, and line up the shift forks as you place the tower back on. Otherwise it's just stuck in gear until you do this. Since you're not having to so this and you seem to be losing a gear I bet you're due for a rebuild on that tranny.

It is a T19 btw, probably can pick one up pretty cheap since everyone wants the ZF.

 

Use caution while removing the shifter. There is a small dowel pin located in the transmission case that can easily fall out. Remove the boot and shifter nut, the dowel pin is on the driver's side, remove it with a magnet or something then pull the shifter. When you reassemble it put a small amount of grease or vaseline on the dowel pin to hold it in place.

 

2nd throws itself out if i dont press in clutch as i let off throttle, been told it was a bent shift fork, i will look sometime this week when i have time and tell you what the problem is. Thanks for all the info guys!

 

I really doubt it's as simple as a bent fork. Usually damage takes place on the tabs on the fork due to ferrous contamination of the oil, combined with slop in the main shaft bearings.

Recently I overhauled one that wouldn't stay in first. The rear main shaft bearing had a huge (1/4") amount of linear play. About a hundred times what it should have. The material from the bearing caused accelerated wear on the shift forks, but only accounted for about .020" past the coating on the tabs, so probably .040" of wear on each side.

The fix was half an hour in the junkyard pulling an entire shift tower assembly and a $200 overhaul kit. These transmissions are very easy to get out since the bell housing can stay in place, and the transfer case comes off first. They are also exceedingly easy to work on *but* I *highly* recommend getting a large set of expander pliers. Mine were not big enough so I used back to back tire spoons to open up the snap rings, but it was a little awkward. I didn't need to use a hydraulic press (though I have one) as all the press fits were gentle hammer off fits.

T-18's did occasionally get bolted in as replacements for grenaded T19's earlier in production due to T19 availability. T-18's had non-synchronized first though so you should already know if you have a T-18.

PS check engine mounts too. A bad one can cause trans to pop out of gears.

 

Hey guys. I just bought the truck you guys are talking about. I got the tranny out of it. I was originally looking for a worn gear. I confirmed it was 2nd gear. When in second gear if I let out of the throttle it throws itself out. I have this transmission torn apart and I am not noticing any noticeable wear problems. Please drop a text if you have any ideas.

 

Shift the tower assembly to feel the detents? Sometimes when a detent spring is broken/sticky the torque thrust from the helical cut on the gear will deflect the gear and nudge the synchro collar causing it to pop out.

 

Okay so I didn't notice anything in the shift tower. However there was a thrust spacer laying in the bottom of the trans. Correct me I'd I'm wrong, but that could definatly cause my issue correct?

 

*Absolutely*. The last one I tore down, that was the pre-teardown diagnosis, but it turned out to be a wasted rear main shaft bearing.

Pretty basic to get in there, the reverse lever assembly can be a pain to get off, and it's gotta come off to get the clusters out. I had to weld a bar to the torx bolt and hammer it off. Other than that it's really easy. Getting the gears apart for doing synchros is a little tough unless you possess a monstrous set of expander pliers. I broke mine and wound up using a pair of curved prybars to overcome the big snap rings.

You don't need to get any of the cluster apart to do the thrust washers though. Just pull the mainshaft gear cluster out and then knock out the counter rod and pull it out. Tacky grease is your friend to hold the needle bearings in place on the counter gear.

The customer was my buddy and on a *tight* budget so I went with a cheaper vendor for the overhaul kit- normally I would have gone with novak just as a knee jerk, but this company had a kit with quality bearings and included baulk rings for $120 http://www.americanpowertrainwarehou.../t18-t19-ford/

There are two versions for the main bearings. Either "thick" or "thin". Do a little homework if you order. Or just measure the width of the bearing on the input shaft.

 

Thank you Thats a big help. I think I will tear the main shaft down and replace the synchros as well. I can get a kit with everything for 200 bucks. I believe it will be worth it once I build an engine. Know of any ways to de-stroke the engine? I'm thinking with shaved pistons and a bigger cam I can run more boost. However if I can destroke it some I can run some big power. I need advice though. I don't wanna lift the heads of this thing by running too much boost.

 

I wouldn't de-stroke it. I do not know of anyone who makes an aftermarket crank/rods so as to be able to. Shaving the pistons and an aftermarket (R&D) cam will be more than enough to allow you to run some boost provided you install head studs. The 6.9 runs a 7/16 stud which is smaller than the 7.3 studs which is a bit of a limiting factor still... You can, however, install 1/2 and possibly 9/16 head studs into the 6.9 block by drilling and tapping TO THE SAME LEVEL AS THE 7/16 do not go any deeper.
I personally have not done this to my engine yet but it is in future plans. This information is from Project Smogie If you want to modify your motor this thread will give almost all information you will need on what to do (and in some cases what not to do).

For parts, probably the best place for the idi is R&D

 

What if I sleeve a 7.3l to a 6.9l? Then I have my thick cylinder walls with my large head studs.