T3650 Noises

thomas91169

I'd donkey punch my sister.
Aug 19, 2005
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Modesto, CA
I know we have countless threads on them. i dont have enough time in the world to even read through a few pages of the issues thread.

but i have a few strange sounds/sensations from my drivetrain that id like to see if theyre normal/abnormal and possible causes.


1) Clunk - say im at a light, clutch is out, shifter in neutral. ill engage the clutch and put her in 1st to get ready to take off, and ill feel this "THUD" as the shifter goes into 1st. :shrug:

2) Rear Backlash? - at low speeds and low rpm's, say you come off the throttle and feel the car decelerate, then hit the throttle again, its almost as if the driveline must wind up before engaging, and then you get this loud clunk(if youre next to a wall you can hear it reverberating off the concrete) as the car lurches forward. i believe its just a combination of the T3650 and rear end, possibly universals in the driveshaft. any input?

3) Tranny Chatter - its loud. usually under part to moderate throttle and load(like 25mph in 3rd or 2nd) you can hear the transmission make strange noises. sounds like a mix of clutch chatter and fluid moving, and unless its in my head, i can almost feel it through the gas pedal.

4) Groan under hot takeoff - i posted this dilemma up before. after a few minutes of driving in hot cali afternoon sun, ill come to a stop. as soon as i take off from this stop at any pace(though mostly normal takeoff with traffic), theres a loud moan that emits from the rear. it starts from the second it starts moving to about a few feet out of the hole, or 5ish mph. i ruled out brakes, as all rear brakes have been replaced(thinking frozen calipers), now i am pointing towards differential and possibly the trac-loc(85k on her btw) unit. it used to do this sound every so often, but the hotter the ambient temps get, the more consistent the noise gets. im betting in winter it will dissapear completely, but id rather fix the problem now. if i can track down the problem to the rear thatd be awesome, cause gears+rebuild kit(or built 31 spline/eaton posi if funds permit) are in the plans anyways. but if its something else id like to know if anyone had the same issues.

5) Turning+Braking=strange feel from rear - this i believe goes hand in hand with the above dilemma. when coming into my driveway, in 1st gear at low speeds, slightly decelerating as i come up the curb, you can feel the rear bounce back and forth, like it cant figure out which side to slow down first. which could explain a fubar trac-loc that needs attention.


i have changed all fluids with Royal Purple in hopes of maybe a cheap fix, but to no avail. the 3650 shifts better than before, pretty smooth i must say, now theres no notch between 1-2 and 2-3 slides like butta.
 
thomas91169 said:
i have changed all fluids with Royal Purple in hopes of maybe a cheap fix, but to no avail. the 3650 shifts better than before, pretty smooth i must say, now theres no notch between 1-2 and 2-3 slides like butta.

how much did you put in?

i was reading that loooong ass thread and somewhere it said to use 3.2 (litres or quarts?) of non-synthetic fluid, like texaco dexron III instead of synthetic:shrug:



i've got the rear backlash problem on my car, ford dealer of course said it's normal. doesn't bother me near as much as the fact that my car doesn't like going into 2nd, hot or cold. no noises or grinding, just lots of resistance

i get rid of that and i'm happy
 
3 quartsof RP Synchrotech or whatever its called. it made the chatter before the fluid change with the last change(using motorcraft atf fluid), and even before that change(when i got the car) though it was not as apparent due to the excitement of finally having a 5spd+rwd+torque.