FMX makes strange noise after hard acceleration

Robsweden

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Hi

Yesterday I did a strong kickdown with my mach 1 73, 351c and it took of like a rocket. I let go of the gas and after when getting around 1800 rpm there was a noice comming from the FMX transmission. The FMX is standard but with a fresh torque converter that is capable of handling 500 hp, stall 2500.  I have not taken it for a spinn again, I will friday.

I understand its hard to diagnos a sound like this, but has anyone encountered something simillar ?

The noise was  pretty low frequency, almost like a drill at lowspeed metal against metal. I have not taken away the pan yet.

Regards Rob

 
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Do not presently own a '71 to '73 Mustang
Do you get the noise anytime the engine is running? Is the noise only there in drive and reverse?

Don

 

Robsweden

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Hi

Only in Drive when hittinh 1800 rpm's When in parking revving the Engine no noise at all.

Rob

 

72HCODE

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check 1st ,2nd lock the shiftier into 1st and 2nd and see if you hear the noise and that the car rolls easy.

I nuked 1st and the car was slipping in 2nd and wouldn't shift into 3rd. so it was running off just 2nd gear. when i shifted into 1st manually the drive-train locked up and the engine stalled.

 

Don C

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Did you check the fluid level with engine running and transmission in park or neutral? When cold it should at or a little below the add line.

 

Robsweden

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Hi

Fluid level is okay

Il give it a try with manual shifting and see if the noise comes back.

Thanks Rob

 

Robsweden

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I took the car out for a spinn today, not a sound the FMX shifts as it should ..

Happy...but I better stay away from burnouts..

Regards Rob

 

72HCODE

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you could of knocked some clutch material out of the packs and that was getting hung up and making noises, once the material broke up more it went into the pan and now it isn't making noises.

there could of been some damage to the internal sprang as well. you won't know unless you find a roller bearing in the pan or clutch material in the pan when you drop it for a fluid change.

point is if you plan to do a burnout in the future expect it to cost more money each time you do it.

when my trans blew it was acting kind of funny the last 2 times i took the car out and i did a hard acceleration to churp the tires for a buddy riding with me in the car and boom i fused 2 clutch bands together locking out 1st gear and blowing 3rd gear in the process and the trans would only run in 2nd and it was slipping badly. limped it home thank god. now as it turns out the trans place that rebuilt that trans did not, and the entire transmission was junk anyway and not original to the car, so i built my own transmission from a fellow forum members 1973 Q code.

 

Robsweden

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I finally had the FMX rebuilt by a professional.

Shift kit and a lot of new stuff

this was inside , the front band or what its called was totally wrecked :)





I now running it with GULF ATF Type F

 
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