Delay in Transmission Shift Accompanied by Excessive Fan Noise

[Campforlife]

Looked for a while and did not see a thread than answered this question. Perhaps I missed it.

Intermittently on acceleration from a stop it sounds like the engine fan spins very fast (the typical jet engine sound I've read about) and it seems to delay the transmission shift into the next gear quit a while. I'm thinking till about 2,500 + RPMs Feels like a loss of power as well.

Fan does not feel lose. Has resistance that feels consistent and good. Spins about 1/5 of a rotation when hand spun.

This 03 Trailblazer LS I6 2WD was purchased a few weeks ago with 131K miles. Need it to last as the primary family vehicle for about 2 years while we save for a newer one.

1. Any ideas on the fan noise in conjunction with the transmission shift delay?

2. I've read that changing fluids especially in the transmission late in the game can cause problems but also read from people on this site that obviously know more than I that it is a must when acquiring a used vehicle you don't know the history of. I'm guessing that the philosophy here is that you go ahead and do it and if problems arise then deal with them too under the theory that you have a vehicle in tip top shape in the end? Oil of course changed and fluids topped off.

For those of you who may recognize the screen name, all other problems have been resolved thanks to this site/ you. Lose ground fixed a myriad of issues and blower motor resistor replaced to gain all settings back on the dial. Also, cleaning the throttle body had a noticeable impact on idle when the AC is turned on.

Thank you.

 

[Campforlife]

The silence says that everyone is sick of "Fan Noise" posts. I don't blame you! I just could never tell from other posts old and new if the high fan speed along with delaying the shift with what feels like a loss of power was anything to worry about or just normal. Manual says it is normal (page 5-36) but it doesn't feel normal.

Sure are A LOT of clutch fan posts for about the last decade. But I guess with no "play" in the fan in any direction and what feels like a normal amount of resistance when spinning I won't worry about it for now. Hopefully all is well.

Truck runs about a tick or 2 below the 210 mark on the temp gauge.

 

[Blckshdw]

The lack of posts doesn't mean we're sick of seeing the issues. More like those of us who've seen the thread so far don't have an answer to give. And guessing isn't highly looked upon

I can say, if your temp gauge only gets to 1 or 2 ticks to the left of 210 on the guage, your thermostat is stuck open and needs to be changed. It hasn't thrown the P0128 code yet, but it's making you run rich, and will eventually plug up your cat if left unchecked.

 

[IllogicTC]

Say, wasn't there a PCM update a while ago involving delayed 1-2 shift in certain temperature conditions, and some issue with the fan?

Also, I would advise having a scan tool for ANY modern vehicle owner. Whether it's an actual scanner, or an app with a bluetooth dongle. The dials in the cluster are fickle things, and not always to be trusted. I would say it is best to confirm the temperature via a scanner just to be sure the temp gauge isn't lying to you. For example, at 190 mine reads just a hair over the 210 mark, while at 180 it reads a full tick below.

 

[Campforlife]

What is a PCM update? Computer update? I'll think I'll invest in an app version of a scan tool with my phone although it sounds like just enough information to get me into trouble.

Thermostat diagnosis sounds like it might fit. I have noticed it dip on an occasion or two well below the 210 mark briefly and then back up. Does that sound like confirmation to you?

Thanks.

 

[Campforlife]

Can you recommend a Bluetooth dongle?

 

[Blckshdw]

What is a PCM update? Computer update? I'll think I'll invest in an app version of a scan tool with my phone although it sounds like just enough information to get me into trouble.

Thermostat diagnosis sounds like it might fit. I have noticed it dip on an occasion or two well below the 210 mark briefly and then back up. Does that sound like confirmation to you?

Thanks.

The PCM sits on the driver's side of the engine, just behind the alternator. I don't know if there was an update or not, but if there was, and the dealership(s) in your area wanted to charge you for it, I would look at getting your PCM tuned for a little better performance. PCMofNC is highly recommended by many members here, myself included.

Can you recommend a Bluetooth dongle?

Any bluetooth ELM327 dongle you can find on Ebay or Amazon will be fine.

 

[Mooseman]

I do believe there was an update for that exact problem but it can be done only by a dealer with a Tech2 scan tool or an independent shop that has one. It's not a matter of downloading a firmware update and uploading it to the PCM (like with a router or computer).

However, if you can use another vehicle for a while, you could send your PCM to PCMofNC to be reprogrammed or tuned. Apart from putting in the latest programming for your truck, they could also tune it for better power and fuel economy as well as firm up shifts. It might cost as much or a little more than a trip to the stealership but well worth it. If you need to keep your truck functional, they do have a loaner program but it adds some costs.

 

[Campforlife]

Thank you gentlemen. I'll check with our local Chevy dealer to see if they are aware of such an update.

This mail order PCM Of NC thing is completely new to me but very interesting. Thanks for sharing.

Think I'll invest in and "ELM327" blue tooth device as well. Any advise on how to get that purchase past the wife? Just kidding, thanks for the info guys. God Bless.

If in fact there was a PCM update that fixes the issue I was having I will post it here for the benefit of others.

 

[IllogicTC]

Thank you gentlemen. I'll check with our local Chevy dealer to see if they are aware of such an update.

This mail order PCM Of NC thing is completely new to me but very interesting. Thanks for sharing.

Think I'll invest in and "ELM327" blue tooth device as well. Any advise on how to get that purchase past the wife? Just kidding, thanks for the info guys. God Bless.

If in fact there was a PCM update that fixes the issue I was having I will post it here for the benefit of others.

The bluetooth device doesn't work by itself - it works in conjuction with an app, typically Torque Pro on Android is what people around here suggest. Total cost is $25-30 (device and app) and provides the versatility of a $200+ scanner, easily.

 

[Campforlife]

Got it. Thank you.

 

[Mooseman]

Just so we're clear, the ELM327 will work ONLY on Android devices. Apple, in their infinite wisdom, will not allow bluetooth connections to apps. If you have an Apple product, there are WiFi versions of the ELM327 but not sure of apps for it and I think it's pricier.

 

[Campforlife]

Yep. Have an Android phone but will probably confiscate the kid's Kindle so I have a larger screen. Ordered a $25 ELM327 from Amazon tonight and will download Torque Pro App tomorrow.

NOTE: I've never thought of myself as a victim much in life. You get what you work for. (The harder I work the luckier I get.) But I have to say that auto repair is the one area I've often had that bitter feeling that I am getting screwed. It is nice to feel like I am a bit more in control. I appreciate your help.

 

[The_Roadie]

Make sure the Amazon Kindle store even has the torque app. My short experience with a Kindle Fire made me think it was Android only at the core, smothered and made evil by the restrictive Amazon ecosystem layer.

 

[Campforlife]

Good point.