06 - Harsh Upshifts

We just purchased an 06 Uplander. It currently has 65300 miles. My wife came home a couple days ago complaining that it was shifting hard. (of course we are just over the car lot warranty mileage!)

I drove it last night after it sat all day. I drove about 13 miles and it shifted fine. It sat for about 2 hours and then I drove it home. About half way home I noticed that it started shifting really harsh. It is hard to describe, almost like it is slamming into gear. I watched the tach and didnt notice any noticeable increase in RPMs so I dont think its slipping and then catching.

Any thoughts/ideas? Would a tranny fluid flush/change help?



Thanks,

Gary

I found the following TSBs, can anyone provide the complete TSB?

Service Bulletin Number : 080730002 Date of Bulletin : MAR 01, 2008
NHTSA Item Number : 10025065
Component : POWER TRAIN:AUTOMATIC TRANSMISSION
Summary : INFORMATIONAL ON 4T65-E MN7, M15 AND M76 FRONT WHEEL DRIVE AUTOMATIC TRANSMISSION VALVE BODY RECONDITIONING, DTCS P0741, P0742, P0757, P842, HARSH SHIFTS OR SLIPS. *PE


Service Bulletin Number : 08-07-30-002 Date of Bulletin : JAN 01, 2008
NHTSA Item Number : 10025561
Component : POWER TRAIN:AUTOMATIC TRANSMISSION
Summary : INFORMATION ON 4T65-E MN7, M15 AND M76 FRONT WHEEL DRIVE AUTOMATIC TRANSMISSION VALVE BODY RECONDITIONING, DTCS P0741, P0742, P0757, P842, HARSH SHIFTS OR SLIPS. *PE

Well, the tranny shop said I had the P1811 Max Adapt/Long Shift code. They also said there was some metal flakes in the filter, more than they like to see but not too bad. They said they did not feel a catastrophic failure was impending.

They are wanting $1350-1500 to redo the valve body. They said this is a known issue with these transmissions. Is there anything else that could cause this code?

For now I had them put it back together with a new filter and fluid. We are just going to drive it for now. It doesnt do it all the time. Im hoping we have a bit of time to save up the $$$ for the repairs.

Our uplander does sort of the same thing. Although it feels like the tranny is slipping kinda. At a redlight on a warm day, it will rev just a little and then catch and lay a bit of rubber and snap your neck so you can curse and curse at it. Any light shed?

See Buick>Century thread, "Great Solution for 4T65E Hard Shift, P1811 DTC" for a possible inexpensive fix. My wife's Century developed the hard shifting, and BNaylor's simple fix referenced there cured it. Hope it helps you out!:iceslolan

.

For some great info on the 4T65E transmission, surf entire pages at: http://www.tripleedgeperformance.com/4T65E_Transmission_Info.html

Some say that transmission slippage and other problems are common with the 4T65E transmission. Especially transmission with high mileage.

To "buy some time", one might want to replace its existing ATF transmission oil and also dump in a can of Lucas Transmission fix "additive". re: http://lucasoil.hodgsoncorp.com/slipping_transmission.htm Some say this might get another 3-6 months out of transmission. Especially if one's transmission is plugged with dirt. Thus, allowing some time to shop around - or sell your van.

In the end, I recommend one's transmission is pulled and re-built. If going with OEM part replacements, one might want to select a Performance Kit instead. And, install a new Performance Torque Converter as well. Yes. Expensive to fix a slipping transmission but if you plan to keep your vehicle for many more years, installing a "performance kit" (which is better then OEM) is much better in the long run. Do shop around because cost of performance kits do vary.

Also... My transmission mechanic told me that 4T65E transmission does NOT like heat. Hot days, more then 3+ people hauling, lots of internal cargo, aggressive gas peddle, pulling a trailer and/or going up hills is very hard on this "average quality" factory transmission. For my '09 Montana van (under these driving conditions), he recommended I install an Aux Transmission cooler. And if one is buying a cooler, they should spend a few more dollars and get the larger size cooler instead. Once bought and installed, its good for the life of the vehicle. And best of all, he tells me that "cool(er) transmission oil = much longer transmission life". The LPD design and physical size I have in my budget is: http://www.makcotransmissionparts.com/OC-1679.html With his experienced feedback, I'll be installing a large size 11x11 Aux Transmission cooler in my van as well. Well worth it - in the long run...

Hope these items help...

.

.

For some great info on the 4T65E transmission, surf entire pages at: http://www.tripleedgeperformance.com/4T65E_Transmission_Info.html

Some say that transmission slippage and other problems are common with the 4T65E transmission. Especially transmission with high mileage.

To "buy some time", one might want to replace its existing ATF transmission oil and also dump in a can of Lucas Transmission fix "additive". re: http://lucasoil.hodgsoncorp.com/slipping_transmission.htm Some say this might get another 3-6 months out of transmission. Especially if one's transmission is plugged with dirt. Thus, allowing some time to shop around - or sell your van.

In the end, I recommend one's transmission is pulled and re-built. If going with OEM part replacements, one might want to select a Performance Kit instead. And, install a new Performance Torque Converter as well. Yes. Expensive to fix a slipping transmission but if you plan to keep your vehicle for many more years, installing a "performance kit" (which is better then OEM) is much better in the long run. Do shop around because cost of performance kits do vary.

Also... My transmission mechanic told me that 4T65E transmission does NOT like heat. Hot days, more then 3+ people hauling, lots of internal cargo, aggressive gas peddle, pulling a trailer and/or going up hills is very hard on this "average quality" factory transmission. For my '09 Montana van (under these driving conditions), he recommended I install an Aux Transmission cooler. And if one is buying a cooler, they should spend a few more dollars and get the larger size cooler instead. Once bought and installed, its good for the life of the vehicle. And best of all, he tells me that "cool(er) transmission oil = much longer transmission life". The LPD design and physical size I have in my budget is: http://www.makcotransmissionparts.com/OC-1679.html With his experienced feedback, I'll be installing a large size 11x11 Aux Transmission cooler in my van as well. Well worth it - in the long run...

Hope these items help...

.

remove accumulator pack in bottom of pan,,,,re-condition bores with a piece of scotch-bright,,,,,replace O-rings,,,and any broken springs,,,re-install...problem should go away,,,,usually high mileage problem,,,exsists when trans is warm,,,1/2 clunk,bang,,,2/3 clunk,bang ect ect better than tranny-in-a-can !!!!!!