shifting problems???

[drob99]

Hey, mostly when I'm driving my car shifts kinda hard when changing gears. Its really annoying. Sometimes its hard and sometimes its not. Also when I put my car in reverse from park after its been sitting a long time like overnight it has a loud bang like a drive over something. But if I start my car idle for 1-2 min then I dont hear the loud bang. Can u tell me whats wrong with my car. I have a 2002 Grand Prix GT with 87K

[BNaylor]

Normally hard shifting is a pressure control/line pressure issue. Get it scanned and see if any tranny codes are stored in history. When was the last tranny service - ATF and screen filter?

[drob99]

I only had the car for about 2 years and I've never done any transmission service to it.

[BNaylor]

Start there. It is due anyways. 100K mile service. Do not flush. Just a pan drop service only replacing the screen filter and fluid. About 7.5 qts. You can use Dexron III or the new Dexron VI ATF.

[drob99]

I was told if I do a transmission fluid change too early it would mess up the transmission and make it worse.

[BNaylor]

Not necessarily. It can't be any worse than it already is.

[00GTP4ME]

Originally Posted by BNaylor

Start there. It is due anyways. 100K mile service. Do not flush. Just a pan drop service only replacing the screen filter and fluid. About 7.5 qts. You can use Dexron III or the new Dexron VI ATF.

Bob, why don't you want to flush the fluid, out of curiousity?
drob99, when I got my GTP, it had 68K on it (at 122K now) and I've done a tranny service every 25K, and the transmission is as smooth as butter. I highly recommend that you make a tranny service a regular part of your maintenance routine.

[BNaylor]

Originally Posted by 00GTP4ME

Bob, why don't you want to flush the fluid, out of curiousity?

Good question. It is an old issue we have covered over and over through the years here at this forum. Just to make it short just reference our old threads on the subject. Here's a good one and the best explanation I think I have ever provided is at post # 7.

http://www.automotiveforums.com/vbul...ht=power+flush

Originally Posted by BNaylor

Other than a general concensus in this forum probably not. There have been a lot of horror stories. Some had success with flushes. But first the data should be split or differentiated between what type of flush are we referring to? Technically there are two types performed or even recommended by GM. There are different flush fixtures used by GM dealers, trans shops and the fast lube places. GM only recommends two specific types.

They recommend one brand of fluid exchanger (Wynn Transerve) and one brand of flusher (Kent-Moore). Then on the flushing it was recommended only if there was a transmission failure or problem, otherwise not for routine maintenance. Also, GM only recommends a certain approved flushing detergent to encapsulate fine particles which is used with the real flush machine. The fluid exchanger which is technically not a flusher will not remove particles because it is low pressure and uses the tranny's pump.

I believe the bottom line is this, GM only recommends flushing if there is a problem, otherwise they only recommend a fluid exchange using the Wynn Transerve or similar probably to get all ATF out to include in the torque convertor which is really only for convenience and ease of maintenance.

Most of the flushes ever mentioned are not real flushes but fluid exchange. The fluid exchange doesn't sound too kosher to me and IMO a pan drop consisting of replacing at least 7.5 quarts of the ATF and screen filter is better for obvious reasons.

[00GTP4ME]

Wow! Thanks for the info!

[BNaylor]

Originally Posted by 00GTP4ME

Wow! Thanks for the info!

You're welcome. So whats the verdict?

[00GTP4ME]

Originally Posted by BNaylor

You're welcome. So whats the verdict?

Do you mean which do I agree with (flushing or not flushing)?

[BNaylor]

Originally Posted by 00GTP4ME

Do you mean which do I agree with (flushing or not flushing)?

I made it easy for everyone. This thread is now a poll.

[richtazz]

no flushy flushy

[00GTP4ME]

I read that thread and there was wealth of what's, but I didn't quite catch the why's. Someone mentioned that doing a true flush can "shock" the system. Why is that? If we had some variety of bio-transmissions I could follow that, but I'm not following what damage occurs by flushing? I'm not saying I'm disagreeing with anyone, I'm just trying to get my mind around the whole concept.

[BNaylor]

It depends on what flush we are talking about. The real power flush done by the dealers or even transmissions shops is intended for malfunction not as preventive maintenance. If you check the GM factory service manual for our GPs there is no mention of flushing the transaxle. The fluid exchange service is really not a flush but replacement of just about all ATF in the system which includes the lines to the radiator and whats left in the torque converter but the screen filter is not replaced during the process. More of a money making deal for the quick lube places and even dealers. I've never had any of my GM cars flushed. Just a pan drop service and screen filter. Plus it is cheaper.