My transmission failure

[frdwrnch]

Oh well, it happens to the best of us. During a "Wide Open Throttle Event" I heard a thud and lost 3-4 gear at about 110. I did not cancel the overdrive during this manuever but I dont think that was a factor in this failure. I think the output shaft drum sheared at the shaft weld. I'll get it fixed next week. Has anyone experienced this failure and are there any beefed up parts around to prevent it? Bryan?

[Kennyrauder]

You did a no no! Never have o/d in function under WOT. Happy New Year.

[FordNut]

Bummer. Usually it kills them when you're in od and stomp it, causing a 4-2 downshift. You have an '04, so it's a 4R75W and most of the internal parts are as good as they get. The main improvement is the spiralock clip instead of the OEM snap ring. You may have broke the snap ring or snap ring lands, maybe even broke the stub shaft. I've had both types of failure and it would still go in 1st & 2nd.

[frdwrnch]

I think it's the stub shaft. It did not occur during a downshift, just wound out in third. Any beefed up parts for this?

[FordNut]

Supposedly an aftermarket hardened stub shaft, but according to what Jerry W told me, the one from Ford is already hardened. Maybe you could get one of those and have it cryo-treated. Lentech also has a stub shaft and drum upgrade that has more splines, but since the shafts usually break instead of stripping the splines I'm not sure if that would solve anything.

[Marauderman]

Bummer. Usually it kills them when you're in od and stomp it, causing a 4-2 downshift. You have an '04, so it's a 4R75W and most of the internal parts are as good as they get. The main improvement is the spiralock clip instead of the OEM snap ring. You may have broke the snap ring or snap ring lands, maybe even broke the stub shaft. I've had both types of failure and it would still go in 1st & 2nd.


I think it's the stub shaft. It did not occur during a downshift, just wound out in third. Any beefed up parts for this?

Exactly what happen to me--@ 120 in third but ..thats another story--it was the stub shaft twisted into two pieces---

Russel--Call Dennis --He fixed this for me----he can for you as well--Ask him to remember back to mine--I had it shipped to him from my place and in less than 18 days between his place and me had it back in and still running today --you might remember my incident if you think hard--righ after I got home with my new S/C in Dec. '03.... good Luck....Tom

[mgmsleeper]

You did a no no! Never have o/d in function under WOT. Happy New Year.

ok im new to this topic, plz inform me.

do u mean dont turn off OD at WOT? or dont have it off then go WOT?

[FordNut]

Make sure and turn it off before going WOT.

[mgmsleeper]

Make sure and turn it off before going WOT.

....figured that. I just worded it wrong. Thanks

[Dennis Reinhart]

Oh well, it happens to the best of us. During a "Wide Open Throttle Event" I heard a thud and lost 3-4 gear at about 110. I did not cancel the overdrive during this manuever but I dont think that was a factor in this failure. I think the output shaft drum sheared at the shaft weld. I'll get it fixed next week. Has anyone experienced this failure and are there any beefed up parts around to prevent it? Bryan?

You will have a complet kit, incliuding a hardened stub shaft and a forced lube kit on me Russel. Have a safe New Year.

[frdwrnch]

Thank You very much Dennis. Here it is. Did not twist, just broke clean.

[babbage]

If you have O/D in cancel mode (no overdrive) and you're floored with 4.10's -- what is the max speed in 3rd @ 6000 RPMS? -- 120?

[babbage]

Thank You very much Dennis. Here it is. Did not twist, just broke clean.

wow - did you tear into it yourself?

[frdwrnch]

Transmissions are one of the very few areas that I am not trained in. I can perform periferal repairs but not full assembly. Fortunately I have one of the best transmission technicians in the area working for me and he makes it look easy.

[FordNut]

The best 4R70W trans I ever had in my car was built by a transmission guy at the Ford dealership, using a kit from Dennis. You can't go wrong with that.

[dohc324ci]

^Thats good to know...I am going to do the trans before boost.

[ImpalaSlayer]

so is the 4r75 better then the 4r70?

[FordNut]

so is the 4r75 better then the 4r70?

Yes. The pump is different, it has bigger flow passages. The way it engages the clutch pack is different, it has contact in the full circle rather than in 3 points. The planetary gear is stronger. I learned these things from Jerry W when he was redoing my 4r70w and he put these 4r75w internal parts in it.

[ImpalaSlayer]

Yes. The pump is different, it has bigger flow passages. The way it engages the clutch pack is different, it has contact in the full circle rather than in 3 points. The planetary gear is stronger. I learned these things from Jerry W when he was redoing my 4r70w and he put these 4r75w internal parts in it.

so in other words the 75 is less likly to break with say 500 ish wrhp?

[FordNut]

I would think so.

[ImpalaSlayer]

I would think so.

sweet. i figured it was just as weak as the 70. gives me a little comfort, now to get rid of that pesky stock engine.

[frdwrnch]

I'm back on the road. Thanks to Dennis for expediting my parts. We installed the new stub shaft, heavy duty clutches, Kevlar overdrive band and forced tailshaft lube mod. I really need to get the shift strategy fine tuned and then it will be a done deal.

[Dennis Reinhart]

Thank you Russel will dial the shift points in next week. I am working all day tomorrow.