Changing shift points... - Transmission Forum

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Changing shift points...
Thursday, October 27, 2005 12:19 PM
Hey guys, I'm a bit new and have an '01 Cav with a 2200 - 3 speed Auto. I don't like how much effort the car takes to get from 2nd to 3rd and want to lower the "shift point" to get into 3rd. I know it's no walk in the park but would like to ask the following:

Is the shifting controlled electronically or mechanically?

What part of the car do I need to be "playing with" to change the shift point and how do I go about it?

Has anyone here done anything similiar?

Is there a guide or someone who could explain things a bit better for me?

Thanks for all the help guys

Re: Changing shift points...
Thursday, October 27, 2005 6:14 PM
Newer transmissions are electronically controlled. Have you changed or added any transmission fluid? Using the wrong fluids can cause problems in the transmissions. All transmission fluid is the same, it's the additives that make them different. Manufacturers put different additives in the fluid to make it act a certain way. So if you added or changed the fluid, did you put the right fluid back in? Also, if the fluid is low it can cause the transmission to act different. Is the MIL/CEL on? If so have it taken to a dealer or auto zone, as they have scan tools and can retrieve DLC's. Have the DLC fixed. And see if the problem is fixed.
Re: Changing shift points...
Thursday, October 27, 2005 6:48 PM
I'm sorry if I didn't explain right Jeff, but my post isn't about something that is broken on my tranny, everything on my car is working just fine. I just want to lower the speed that is required to make my car shift from 2nd to 3rd gear since I feel that it would benefit my driving style more, and because the stock shift points (again, from 2nd to 3rd) make the engine stretch further then I would like.

So again, what "tools" would I need to modify the shift points for the '01 Cav with a 2200 3 speed?

Thanks again
Re: Changing shift points...
Thursday, October 27, 2005 7:30 PM
The 3 sp 3T40/TH125C is mechanically controlled. The Shift points are controled by the Throttle Valve (TV) cable, which is connected to the throttle(the cable is located under the throttle cable).
If the "shift" you are felling occurs above 40 mph, at very light throttle, you are probably feeling the Torque Converter Clutch(TCC) lock-up is often confused with a gear shift. The TCC is literally a clutch the locks the TC, so there is no fluid slippage.
If you do need the 2-3 shift (under light throttle this can occur at as low as 25mph) adjusted, you can adjust the cable in, by pressing the button on the cable mount and sliding the cable in. Be advised, move one notch at a time(they can be very sensitive), then test drive the car. This will affect both the 1-2 and 2-3 shifts, as well as the TCC lock-up. Also, be warned, if you move the TV cable too far you run the risk of doing damage to the tranny.





Re: Changing shift points...
Thursday, October 27, 2005 8:13 PM
Hey MadJack, thanks for that bit of golden info. I will try playing with it a bit tomorrow and will heed your warning about going "too far". My last 2 questions on the subject are:

Do I feed the cable towards the firewall if I want to lower the shift points or pull it back towards the bumper?

Is there a way to modify ONLY the shift from 2nd to 3rd?

Thanks again for the help
Re: Changing shift points...
Thursday, October 27, 2005 8:16 PM
Grrrrrr I wish we could edit posts. I forgot to mention in the above post that I am sure what I'm feeling is the true shift points as I am referring to the ones "felt" at WOT (1st to 2nd in this case is at around 35mph).

Out of curiousity, what kind of damage from going too far with the cable are you talking about MadJack?
Re: Changing shift points...
Thursday, October 27, 2005 8:20 PM
its a 3spd Auto, the gear ratios arent good enough to do what you are wanting (my Sunbird has a 3spd, 2nd went in at 45ish, 3rd at 80 so i know what you mean). Best bet is getting a 4spd tranny swap, or a manual.


Re: Changing shift points...
Thursday, October 27, 2005 8:29 PM
I'm glad/sad someone else knows my pain Ender.

Would you mind telling me the model no. for the 4spd tranny and what will need to be don't to make it fit / work on my car?

Thanks
Re: Changing shift points...
Friday, October 28, 2005 7:05 PM
Changing the gear will make a big differenceon the WOT speeds during shifts. Mine, like most (but not all) 3rd gens came with an effective gear ratio of 3.18:1. This ratio is determined by the final drive ratio and the drive chain. There is three different final drives(fd) that were made for the 3T40/TH125C; 2.84:1, 3.06:1 and 3.33:1. there were four different drive chains made for it also, they were; 35tooth/35t(1:1ratio), 33t/37t (overdriven), 32t/38t(realy overdriven) and 37t/33t(underdriven). Mine came with the 37/33chain and the 2.84fd, wich equalled the 3.18 effective drive. I changed out the 2.84fd for the 3.06fd, for an effective ratio of 3.43. I now turn about 2873rpm at 60mph, but the torque is much greater. See my profile for more info on what I've done to my tranny, which closely resembles what Event did to his. See what Event did here.
If you decide to change the fd, go ahead and do the whole tranny, since the fd resides in the deepest part of the tranny!

Also the are many stock stall speeds for the 125, if you go N/A (see you local performance tranny shop that carries DACCO or TranStar). My stock was 2375rpm, I switched to a stock 2560rpm stall, but I should have done a 2795rpm. If you boost or use laughing gas, definitely go with a custom aftermarket TC, to prevent balloning the TC.





Re: Changing shift points...
Friday, October 28, 2005 8:07 PM
Dacco and Transtar are lousy choices for a converter.
Re: Changing shift points...
Saturday, November 05, 2005 3:34 PM
Ok guys I must truly apologize to you all as I just found out that I have a 4spd electronic tranny and not the hydraulic based 3spd.

This is very embarrasing but I'll be accepting kicks to the butt for wasting the time of those who posted on this thread :p

In the meanwhile, could someone maybe enlighten me about changing the shift points on the electronic 4spd?

Thanks

Re: Changing shift points...
Saturday, November 05, 2005 4:04 PM
Can't be done, sorry. You'd have to be able to reprogram the PCM, but no one can do it (cheaply, yet).





Re: Changing shift points...
Saturday, November 05, 2005 7:31 PM
buy a manual?


Re: Changing shift points...
Tuesday, November 08, 2005 4:25 PM
kyle 102565, u said "Dacco and Transtar are lousy choices for a converter." Which
one(s) do u suggest? Not tryin to be a prick or anythin, just been lookin into options for my 3t40e "slug".
Re: Changing shift points...
Tuesday, November 08, 2005 7:32 PM
Yank is great, and i'm pretty good. (sorry but i gotta plug) as for mass produced suppliers Precision is ok. keep in mind these large suppliers make 500 a day with a crew of factory workers with little regard to you recieving a converter thats marginal at best. failures are common. i build 5 to 10 units a day with half going into cars in our trans shop or 5 other local trans shops that i know personally. if it fails i hear about it. i'm the only one in my shop. i've worked for a medium size supplier who produced 100 a day. i built roughly 35 to 40 converters a day with a less than one percent failure rate for over 4 years. the shop help was horrid at best, mostly temp workers who had no idea how a converter was built and didnt really give a crap. 20 percent failure rates are not uncommon will large factories and when i get their units to try and rebuild i usually throw them out upon opening them up, they require more work than its worth and i end up with crap. so .... after this longwinded post my advise is to find a small shop. if your looking for performance see Mike at Yank, hes the best in the world, no kidding, GM listens to him. or Rusty at the Converter Shop in Lake Havasu Arizona. i learned alot from Mike at Yank years ago at a seminar, and i use Rustys racing parts alot. hes got awesome stuff. just remeber quality doesnt come cheap.
Re: Changing shift points...
Tuesday, November 08, 2005 9:33 PM
Didn't Yank just discontinue the 245mm converters about 2 months ago? It was my understanding that they have discontinued all FWD applications.





Re: Changing shift points...
Wednesday, November 09, 2005 4:51 AM
i heard something about that and find it odd. the 245 is the easiest converter out there to build, the cores are cheap and they are a reliable converter. the 245mm doesnt get any modifications to it other than strengthening it. stock form they can easily handle 500. i use them to build racing converters able to withstand 1200 hp on a trans brake. maybe Mike just doesnt want to bother with them. if anyone is looking, PM me. i'll give any org member the same config. as Yank was offering. at a much lower cost.
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