Bang or shock when coasting into 3rd - Mazda 6 Forums : Mazda 6 / Mazda Atenza Forum

yesitspeter · 09-01-2009, 09:55 AM

I have a 2004 6 wagon with lots of miles on a Jatco 5 speed.

When I get the transmission good and hot (um, lots of hard shifting, stop and go) I can sometimes get this bang (noise) or hard shock when i coast to a stop. If it happens, it may or may not happen at the next point where I stop. This happens only when I have a tough time in traffic or get a little too spirited. Here's what's odd as well: If I just use the manual shifting mechanism, it doesn't happen at all. It seems my car wants to slow down and hit third before shifting to 1st.

A local trans shop says it may be a cracked "piston" they see often in Jatcos.

Another says it may be something deforming in the transmission due to heat.

My thought is to prevent it getting too hot (which seems to lead to the issue). I have ordered a 19K GVW B&M Trans Cooler, and I'm going to install that.

I was wondering though if anyone had a similar experience. I've been scouring the forums, but have not seen anyone with the same problem.

Do you think the trans cooler may be an effective band-aid?
Can I get away with just changing out the valve body as a fix if that doesn't work? If so, where can I find a good valve body?
How hard is it to drop a transmission and install a rebuild kit on the Jatco? (It doesn't look too hard from the youtube videos out there, I guess I'm more concerned about dropping it and getting it open. )
Should I devise an embedded Linux device to control the transmission through the manual switches in the center console?

I'm starting to think this may be my last Mazda.

Nealio · 09-01-2009, 10:48 AM

It's been suggested that all ATX Mazda6s get a transmission cooler as they seem to have heat issues with our car. I'd say install the cooler and swap the fluid and see if it gets better.

brennan1071 · 09-07-2009, 05:18 PM

i read ur post and considering i probably drive the same way u do, fast, i decided to take my car for a spin and see if it did anything...again like it always does. this time i didnt have a bang into 3rd like normal but i did notice it jumped from 2nd to 4th each time i went from a stop to cruising speed. also went around a turn into a straight and it stayed in 3rd for almost a quarter mile without shifting. i know this has done it before and to get it to shift i have to put it into triptonic and shift it into 4th. my mom and girlfriend have both noticed and asked what the bang is when im slowing down...the bang into 3rd. i dont know if this happens to u but have u noticed if its in 3rd gear and u get on the pedal a little more the rpm goes up but the speed doesnt?? like tranny slippage? bc i know its doing it in mine, in 3rd and 4th gear. my mom even notices that if she has to drive it

09-01-2009, 10:48 AM	#2 (permalink)
Nealio Super Moderator Join Date: Oct 2004 Location: Tampa/Bradenton, FL Posts: 2,440 Thanks: 0 Thanked 0 Times in 0 Posts Groans: 0 Groaned at 0 Times in 0 Posts iTrader: 0 reviews	It's been suggested that all ATX Mazda6s get a transmission cooler as they seem to have heat issues with our car. I'd say install the cooler and swap the fluid and see if it gets better. __________________ 2005 Volcanic Red Mazda6S MTX Hatch OBX - AWR - Mazdaspeed Acc. - Injen - CP-E - Greddy - ProSport - Corksport - Medieval Motorsports - Apexcone

09-01-2009, 09:55 AM	#1 (permalink)
yesitspeter Learners License Join Date: Apr 2009 Posts: 29 Thanks: 0 Thanked 0 Times in 0 Posts Groans: 0 Groaned at 0 Times in 0 Posts iTrader: 0 reviews	I have a 2004 6 wagon with lots of miles on a Jatco 5 speed. When I get the transmission good and hot (um, lots of hard shifting, stop and go) I can sometimes get this bang (noise) or hard shock when i coast to a stop. If it happens, it may or may not happen at the next point where I stop. This happens only when I have a tough time in traffic or get a little too spirited. Here's what's odd as well: If I just use the manual shifting mechanism, it doesn't happen at all. It seems my car wants to slow down and hit third before shifting to 1st. A local trans shop says it may be a cracked "piston" they see often in Jatcos. Another says it may be something deforming in the transmission due to heat. My thought is to prevent it getting too hot (which seems to lead to the issue). I have ordered a 19K GVW B&M Trans Cooler, and I'm going to install that. I was wondering though if anyone had a similar experience. I've been scouring the forums, but have not seen anyone with the same problem. Do you think the trans cooler may be an effective band-aid? Can I get away with just changing out the valve body as a fix if that doesn't work? If so, where can I find a good valve body? How hard is it to drop a transmission and install a rebuild kit on the Jatco? (It doesn't look too hard from the youtube videos out there, I guess I'm more concerned about dropping it and getting it open. ) Should I devise an embedded Linux device to control the transmission through the manual switches in the center console? I'm starting to think this may be my last Mazda.

Remove Advertisements Sponsored Links
Mazda 6 Club Advertisement

09-07-2009, 05:18 PM	#3 (permalink)
brennan1071 Learners License Join Date: Jan 2008 Posts: 4 Thanks: 0 Thanked 0 Times in 0 Posts Groans: 0 Groaned at 0 Times in 0 Posts iTrader: 0 reviews	i read ur post and considering i probably drive the same way u do, fast, i decided to take my car for a spin and see if it did anything...again like it always does. this time i didnt have a bang into 3rd like normal but i did notice it jumped from 2nd to 4th each time i went from a stop to cruising speed. also went around a turn into a straight and it stayed in 3rd for almost a quarter mile without shifting. i know this has done it before and to get it to shift i have to put it into triptonic and shift it into 4th. my mom and girlfriend have both noticed and asked what the bang is when im slowing down...the bang into 3rd. i dont know if this happens to u but have u noticed if its in 3rd gear and u get on the pedal a little more the rpm goes up but the speed doesnt?? like tranny slippage? bc i know its doing it in mine, in 3rd and 4th gear. my mom even notices that if she has to drive it