Hmmmm here we go again

[Late4Work]

Took the tune off and noticed something odd.... While in 5th gear if I let off completely, I feel a clunk..... Only happens in 5th, any ideas?

 

[greenscobie86]

Ujoints? Where does the clunk come from?

Could be old and sloppy trans/engine mounts that rapidly move as the stress/load is taken out of the driveline...

 

[Late4Work]

Well the funny thing is that it didn't happen while the tune was on it, and if I push the clutch in before letting out all the way on the gas, it doesn't do it

 

[Musturd]

Is ur drive shaft tight ?

 

[Late4Work]

I haven't checked, but why would it only do it when the tune is off?

 

[MustangChris]

Check ur shaft

 

[chris91]

Yeah sounds like a weird coincidence that its doing it with the tune off. Throw it on some jack stands and check the u joints at the rear end. Youll more than likely notice some play. Cheap and easy fix though.

 

[vermilion]

auto or 5-speed. if auto, tune could affect shift firmness.

 

[MustangChris]

good point....

 

[Nightmare]

Probably the trans mount.....while you are checking that out, check your shaft....How many miles do you have on it?

 

[Late4Work]

86000 and it's a 5spd

 

[Nightmare]

Do you have an aftermarket shifter installed?

 

[sn95jones]

Mine's got 89,100 miles and mine does this shifting from 1st to 2nd under normal acceleration. I have a tune though, and a short throw shifter.

 

[Late4Work]

I have a short throw.... I'm just trying to figure out why it does it without the tune on it

 

[chris91]

Did you throw the tune back on it to confirm it isnt doing it with it on as well? Also you sure it is only doing it while in 5th? Try driving at a steady speed in another gear and then snapping off the throttle.

 

[Nightmare]

I have a short throw.... I'm just trying to figure out why it does it without the tune on it

The tune should really have nothing to do with a noise in a manual trans.....The only thing that I can think of is that with the stock programming, the engine is idleing a little roughter, transmitting sound and vibration through the trans and up through the short throw (since I am willing to bet that yours dosnt have any isolators). When the car is running on the custom tune, the engine is running smoother and the noise and vibration is decreased.

Some things I would check to "test" out this theroy:
Trans mount
U joints
Depending on the shifter you have, the tightness of the bolts/alan screws holding the handle on
If all of these are good/tight, see if it makes the noise in different RPM ranges..That will help varify the vibration question....also see if it does that in gears 3-4 in those same rpm ranges.....I dont think you have an issue with the trans its self, maybe the tension on the clutch cable, but not something that is internal to the trans.

 

[philly101]

I can put money that's its the Trans mount

 

[Late4Work]

There is no noise, I don't know where that idea came from..... I have tried it in 4th and it doesn't do it, it does idle a bit rougher though...... Can't throw the tune back on it cause it's sold and gone

 

[MustangChris]

get under that critter and take a look. since the tune is gone inspecting the drivetrain is the next step

 

[Nightmare]

There is no noise, I don't know where that idea came from..... I have tried it in 4th and it doesn't do it, it does idle a bit rougher though...... Can't throw the tune back on it cause it's sold and gone

When I say noise and vibration, I would categorize a clunk as well. Unfortunatly, with out being there, I can only speculate. Does it clunk on high RPM or low RPM? I still wouldnt rule out a drive shaft......I had a Ujoint issue present its self a few days after getting gears done in my old 88 gt, and I have heard many clunks in 5th on my ranger letting off of the gas prior to getting the whole shaft rebuilt.