Truck ran great, until the transmission went

[ob1kobi]

Well, the truck was running great, 13. 50 - 13. 60 all at 99. 97 - 100. 78 mph. Best run was 13. 50@100. 78. But then something happened.

This is the scenario, that lead to the problems.

Sitting at the staging lights, building the boost to around 20, she stated chugging real bad, so i backed it off to around 15. Green light hit, let off the brake, mashed the gas, but the truck didn't go anywhere. RPM's did not shoot up, as if it was not in gear, it sounded like it should have been moving. Let off the gas, truck started to roll, so I nailed it again. Truck seemed ok, or so I thought.

Drove back to the pits, tried to back into the parking spot, no reverse. Transmission was tight before, when you shifted into reverse, or drive, you got a nice surge. Now when i shift into reverse, there is a clunk, no surge, the rpm's sound like the motor is under load, but she doesn't move. There is no neutral anymore, the truck tries to take off. There is no first gear either, truck starts out in second. After I am up to speed, and lift off the gas, the rpm's cycle up and down, like the torque converter is locking and unlocking.

Any ideas on what exactly I have done? Being it's the weekend, I can't get ahold of Bill K.



Thanks guys,

Ted

 

[Diesel Freak]

Input Shaft?

 

[ob1kobi]

Would the input shaft only affect reverse, and first? The rest of the gears seem to be ok.



Ted

 

[Diesel Freak]

No clue..... just throwing that out there

 

[LSMITH]

She is T. U. You need a transmission, or at least a rebuild. No big deal though, they will all die eventually with that kind of abuse. Seems sorta premature though, how many runs did you get out of it?



EDIT: sounds as if you lost first and direct at least.

 

[ob1kobi]

Please don't say that :{



Transmission has only been in it for just over two months. I have only had 6 runs in the 1/4, and 3 in the 1/8. I expected it to live alot longer than this.



It doesn't get ran hard unless it is at the track. No street racing, and I don't do any towing either.

 

[KatDiesel]

If it was the input or the output shaft I don't think the truck would move at all, least that was my understanding. But I could be wrong, I haven't snapped either yet. Thats why I am doing preventive maintence with cryo'ed input and output shafts, I don't recall anyone snapping them yet.



Might sound like a stupid question... . whats the fluid level like, and condition of it?

 

[ob1kobi]

I haven't checked it tonight, didn't really think about it. But I did check it this morning, before I went to the track, and it was as good as new. It too is only two months old, and has about 3000 miles on it. I have the double deep transmission pan, and the temperature has only come off of 140 twice so far.

 

[Strick-9]

Sorry to hear about your troubles.



Sounds like you welded the forward clutches together. I've welded my direct clutches before.



Excessive slipping wears away the friction then you have metal on metal and they weld together.



That explains why there no reverse and no clunk into gears. The clunk you normally feel is the forward clutches applying and stopping the input shaft.



The high torque multiplication of your converter is what overpowered the clutches and burnt them out. You'll notice that other trucks with different stators can get away with several 20-25psi launches with no trouble. Your torque multiplication is much higher.



From personal experience the welded clutches will hold for a while if you are in a bind, but mine eventually broke and damaged the hub they ride on.



When's the last time you had a pressure test done? What were your pressures set at?



Wish I could help more. Trust me, I've been there. I know how you feel.



-Chris

 

[Jetpilot]

Ted,



Sent you a pm... . Give me a call.



Doug

 

[Briar Hopper]

Ted, it was really great to meet you and Doug and everybody at MIR. I wish I could have been more help, unfortunately I traveled light, very few tools, not even a drain pan. Not sure what I would have done if it had been ME that broke...

I guess it's good you live close to the track, it would have been fun trying to find a flat bed trailer to get Eric's ATS truck down the 800 miles to home if it had broken.