Lost 4th

[01 Silver]

So on the way home from work yesterday, once I get out of traffic, I notice that the tranny is not shifting into 4th. 1-3 are great, no slipping or banging, just no 4th.

Last week I did the TGHD2 and servos and all has been fine until yesterday. Any thoughts or suggestions?

[01 Silver]

Anybody???

[SlammaDingdong]

Man that sucks!

There are some things you can check that were probably "touched" by your work. I just don't want to get you on the wrong track w/ alot of needless work, so of course check the easiest things first:

- Scan for DTCs to rule out some type of electrical problem: TCC solenoid, throttle position sensor, etc.
- Damaged or missing servo seals, or damaged seal grooves
- Wrong servo pin length
- Leaking servo check ball capsule
- Damaged 3-4 accum piston seals or seal groves
- Stuck valve or binding spring in VB: 2-3 shift valve, AVTA, 1-2 shift valve, 3-2 control valve

You may be able to check and diddle w/ the VB valves/springs w/o dropping the VB. There are slots in the bottom you can get into w/ a small screw driver. The bitch is you still have to drop the tranny pan.

Good luck.

[RedHeartbeat]

the worst part is most times it means time for a rebuild.

[01 Silver]

Thanks for the responses. I think that I am just going to have a tranny shop take a look at it. I just don't feel like going back in there.

One it will double check my work, and two, if its needed to go deeper then I can have some upgrades done to make this more complete.

From the info that I told the guy he seems to think that it could just be the teflon seal on the 4th piston. Of course he will scan to make sure its not something electrical.

[RedHeartbeat]

Here's wishing you luck that it's something cheap and simple.

[SlammaDingdong]

Originally posted by RedHeartbeat@Sep 8 2005, 09:31 AM
Here's wishing you luck that it's something cheap and simple.

[Hit Man X]

First thing that popped into my mind is the 4th piston seal, it's a PITA to install properly... you need something to stuff it into the cover with such as a feeler gauge.

[01 Silver]

Good call Hit Man! That is exactly what happened. From what my tranny guy explained to me is that it is fairly common. Apperantly there is a tool that stretches the seal to install without causing damage and then another tool to shrink once installed. I probably just stretched it too much installing then it got caught and eventually tore.

But I am back up and running and happy again. Of course they went over the entire valve body first thinking that I probably installed something incorrectly. But all was good with the VB so I am happy about that as well. Now time will tell if I hurt the band. Should be ok but time will tell.