T-9 issue

[papak]

Finally got out for a solo blat this morning through the Malibu canyons. On the way back home on the freeway. I lost all drive in fifth gear at 75 mph. I made it home in fourth with no seeming issues. All other gears, including reverse, seem to work fine. There were no new noises or grinding that I could tell. Any one else had an issue like this? The drivetrain is coming out this week (perfect project time now). Just hoping it's a simple fix.:banghead:

Edited March 30, 2020 by papak

[escondidoron]

Need more info on the symptoms.

Does the shifter not go into position, i.e. you can't get it into 5th gear?

Does the shifter feel like 5th is engaging but there is no driveline connection?

 

5th gear is entirely in the tailhousing section of the T-9. It's pretty easy to get to with the 'box on the bench. Send me a PM and we can work out a way for me to forward you a copy of the Ford manual.

 

I've recently been through 3 T-9s.

[papak]

The shifter goes into position just fine. It just seems to lose all drive, as if it had popped out of gear. All other gears work fine. Pm on the way. Thanks

[papak]

Update!

 

Upon disassembly, I discovered that the aftmost circlip on the input shaft had popped out of it's groove, allowing the fifth gear synchronizer to move aft about 10mm. After a lengthly discussion with Chris at BGH Gear Tech, we surmise that in a previous assembly the old circlip was reused. There is a definite wear pattern to one face of the circlip. He also gave me a great insight into lubricant quantity in the T-9, always a source of debate. According to Chris, Ford of England went to 1.9l with the introduction of the "N" gearbox only to find that they were seeing evidence of heat damage to some of the bearings and gears. They had originally done their research on the lubricant (75/80 EP, GL-4) and found that at the higher quantity, it foamed enough that there was a somewhat diluted amount of lubricant going to the wear surfaces. They were also seeing seal and vent leaks. With the later "N" units, you will notice that they moved the fill plug back down on the casting to limit the fill to 1.25l. He said that 1.25 is good for track and "spirited" driving but for cruising, it is safe to fill to 1.5l. This is only possible if you have fabricated a fill plug in the top cover. If you plan on doing so, do it in the forward right corner. When done correctly, you can then make and calibrate a dipstick to check the level when needed. As I recall, 1.25l measures about 5" below the top cover. While you have the cover off, you can add a vent line if desired. The existing vent hole is drilled above an internal sheetmetal bracket that aligns one of the selectors. This serves as a baffle to minimize fluid loss. Drill to fit a bung for an AN-4 fitting and have it brazed or TIGed in place. I fabricated a 12" braided steel hose remnant and mounted it to a 90 degree fitting on top of this bung. Mine comes forward and turns straight up ending in a cross drilled end cap. I'll post pics in a day or two.

 

Just waiting on gaskets and such now before putting it back together.

[papak]

The actual measurement is 5 5/8” below the top surface of the cover. While I have the transmission on the bench, I drilled and tapped for a ¼” NPT plug in the mounting flange of the tail This should allow nearly all of the lube to drain, particularly if you raise the front of the car a bit.

[papak]

When I got it back together, a couple of things didn’t look right and there was a bit of sludge in the bottom of the main case so I decided to pull it all apart and clean/check everything. I ended up changing a couple of the bearings and seals. As it went back together (fairly logical process), I ran into a problem with the ¾ synchronizer not working. As it turns out, while the blocking bars for the third/fourth synchronizer and the fifth gear synchronizer are visually similar, they are very slightly different. Those for the third/fourth measure 4.16mm thick in cross-section while those for the fifth gear synchro measure 4.88mm. In all other respects they measure the same. Hard to spot just by looking but it keeps the third/fourth synchro from working. Fifth will work with either one. The plastic oil scoop ring on the fifth gear hub has been replaced with an aluminum two part filler from BGH. After a conversation with Chris at BGH, I removed what looked like a randomly installed circlip in a groove on the second gear side of the first/second synchronizer. It was quite beaten up from the synchro ring riding on it. Chris said that they often remove it when rebuilding boxes. Not needed and it was a source of unwanted metal particles.

 

While everything was apart, I added a drain plug. Chris said to drill the bottom of the aluminum “sandwich” plate to access the internal passage at the bottom of the gearbox. It an be safely done to accommodate a1/4” NPT plug. Once done, it is obvious that you can additionally relieve a bit more of the passage internally to allow it to flow better. The steel main case is too thin at the bottom to correctly install a threaded plug.

[papak]

The box is finally back together and all gears engage! One of the last frustrations was getting the centering spring correctly mated to the centering pin in the tail shaft. I mounted the gearbox to the bell housing this morning. Is should be back in the car later today.

[escondidoron]

It should be back in the car later today.

 

 

Good to hear.

 

Contact me off list to discuss a drive on Sunday 7 June.