Transmission clunk moving from stop

[balmer_guy]

2005 Montana, regular model 3.4 not the SV6. 4t65E tranny. When I come to a stop, occasionally when I take off the van moves a bit and then clunks. After experimenting, I found that if I move the shift lever to 1, it doesn't clunk. If I leave it in D, it will sometimes clunk.

Id the tranny not shifting into 1st at a stop? Is it like hanging in a higher gear and when the accellerator applied it then shifts to 1st with a clunk? Is there an easy fix like disconnectiong the battery? would a shift kit help? Thanks

[rkvons]

Well I'm not the expert, but I'll ask the obvious questions. How many miles? Have you checked for the proper level of trans fluid? Have you performed a pan drop and fluid/filter change on her, and when?

[balmer_guy]

I left out info. 117,000 miles. I've changed the fluid + filter twice. Once at 60K, and the fluid was turning brown. I installed a B & M trans cooler at that point. Once around 90K, fluid was red. Both times I did the pan drop, installed new filter (no chunks in the pan), I also disconnected the cooler lines and ran new fluid through it until it was nice and red.

Fluid is at the top of the dipstick range. I am planning another pan drop and filter change in the near future, which is why I was considering the shift kit and hoping I wouldn't have to start saving for a new tranny.

[shampooguy]

I have the exact same problem ('05 with 120k miles), and like you, have not been able to produce the clunk when shifting from 1st. I've been doing this for over a year...hasn't gotten better or worse. I think others call it "neutraling in 1st". I also had the hard shifts, but have fixed that with a shift kit. I've wondered if the shift linkage is slightly out of adjustment, but have yet to take it in.

[balmer_guy]

Good idea. I am seriously looking at the shift kit, and maybe mounts. Mine actually starts to move and then clunks. Hasn't done it in 2 weeks. weird!

[la1]

I have the same trouble with my 4T65E in a 2003 Impala. I think the whole issue is electronic. My theory is there is a wire(s) in the 20 way connector that have an temp open or the wires have slightly broken in the crimped sockets....or at some time a machanic, checking for continuity or a voltage or whatever jammed a regular DVM probe tip in the sockets which would cause them to expand or back probed the connector allowing moisture in. I can controll when my trans will clunk. I first diconnected both terminals on the batt, negative first and neg last when connecting back up. With the bat disconnected I removed the connector. It is difficult to remove will post the factory manual how to. Squirted some electrical contact cleaner in both ends...worked great for a month. Now I found when the trans starts clunking if I push in on the wires in the 20 way connector, it stops for a week or two, then it starts again. I am going to buy a 20 way connector and see how it does.