transmission thump? Options

[soven]

Anyone notice or know what this is? It is a minor thump as though a shaft has just engaged right under the center of the car when they are for example, cruising on the motorway and then getting off the gas completely. When you get back on the gas, there will be a slight thump sound as though something just engaged...

This is for an automatic

*edit

Just changed front and rear engine mount. The clunk is still there.

Diagnosis:
Single thump when I lift off gas completely while vehicle is moving and then accelerate harder than usual.
Does not happen if i step on the gas slowly at first and then accelerate hard
Rev-ing engine in Neutral does not produce the thump
While stationary, Handbrake on and stepping on brakes and I shift from Neutral to Drive. I can see the transmission/engine move and also a sound can be heard coming from the transmission area.

Any input? Would the mount under the airbox be the culprit? Transmission fluid is a healthy red colour and at correct levels. Axles? Any other thing I can do to rule out potential problems?





This post has been edited by soven: Jul 19, 2007 - 5:42 AM

[94celigts]

i have noticed this in my automatic too, i thought it was a knock in the trannybut i guess if it happens to you as well it cant be too bad

As well a thing i notice is when accelerating really quickly a rattle from in the middle front of the car sounds like plastic, or a heat shroud... from the outside i think.. anything?

[soven]

I have two celicas atm, I dont have the transmission issue in my SS1 automatic celica. Only have it on the ss3 one.

I do have the rattle sound tho(somewhere in the engine bay) in the SS1 when i accelerate quickly while the ss3 does not have any rattles.

[94celigts]

hrmm i wonder what it is??? anyone know i would love to stop it!

[NaderG]

i think i have the same thing with my tranny , my tranny is in very bad shape though ... sometimes i think it slips ... but i am not sure

[Bitter]

check the mounts on the motor and the trans mount.

[NaderG]

concerning mounts , when i put my car in D or any gear other than N or P , the car shakes , so i am thinking it is one of the tranny mounts ... so how hard are they to change ?

[Bitter]

not sure, i've only done other cars mounts. usually is pretty easy tho. check the front mount also, that can cause a rougher than normal idle.

[Hanyo]

I have the same problem.

My car only had 53k miles when i started to notice this thump sound.

I have no clue what it is, then again, I'm terrible with transmissions.

[soven]

http://www.6gc.net/forums/index.php?showto...14&hl=thump

This sounds like the same problem.... but his one is a gt4...

[SlowCelica94]

It's likely a mount. But also check your fuild level (hot while the engine idels, or whatever it says on the dipstick) and inspect the tranny and it's associated lines for leaks.

[soven]

where are the mounts?

I found the engine mounts in the engine bay and one underneath the car(right above crossmember)

Where are the others? pics or directions would be great

[NaderG]

where are the mounts?

I found the engine mounts in the engine bay and one underneath the car(right above crossmember)

Where are the others? pics or directions would be great

X2 , i can use some direction to find the mount , also how to know if they need replacement

[SlowCelica94]

It's been years since I've been under a 6gc, so I couldn't tell you. Off memory, I think it has a lower mount that goes to a crossbrace, a back one and the frame rail one.

Don't take my word on that tho, just look around for the thingies that hold the tranny in the car.

[soven]

changed front and rear(tranny) engine mounts and the clunk is still there.

[soven]

edited first post.

[soven]

update*

Went to a gearbox shop and got the transmission flushed and filter changed. Nothing wrong with transmission, they say that they notice the sound coming from the differential axle arm(or something like that) and it is common. Told me not to worry about it.

[garygarrett1]

update*

Went to a gearbox shop and got the transmission flushed and filter changed. Nothing wrong with transmission, they say that they notice the sound coming from the differential axle arm(or something like that) and it is common. Told me not to worry about it.

If it wasn't there from the factory I think it is something to worry about, I have this same type of issue on my Dodge ram and it only does it when it shifts from first to second and only every blue moon.

I have no clue in other words.