K2500 transmission question

I have a '95 Chevy K2500 pickup, which was previously a farm truck and has the heavy hitch on it for pulling farm wagons, etc. The transmission (automatic overdrive) has apparently been tweaked for
this heavy pulling, as it seems to shift annoyingly late under normal driving (when there's no heavy load on it) especially the 1-2 shift, and somewhat on the 2-3 shift. I would like it to shift normally, since this truck is just a spare vehicle and won't regularly be hauling/pulling any heavy loads, probably ever. Is this late shifting the result of a shift kit having been put inside the transmission, or is it a function of the controller? TIA
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On Wed, 23 Dec 2009 06:48:50 -0800, burboun snipped-for-privacy@msn.com (burboun supreme) wrote:

Have you tried to disconnect the battery and let the ECM/TCM 'forget' its adaptive learning?
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Burboun: "I have a '95 Chevy K2500 pickup, which was previously a farm truck and has the heavy hitch on it for pulling farm wagons, etc. The transmission (automatic overdrive) has apparently been tweaked for this heavy pulling, as it seems to shift annoyingly late under normal driving (when there's no heavy load on it) especially the 1-2 shift, and somewhat on the 2-3 shift. I would like it to shift normally, since this truck is just a spare vehicle and won't regularly be hauling/pulling any heavy loads, probably ever. Is this late shifting the result of a shift kit having been put inside the transmission, or is it a function of the controller? TIA " ********************************************* Peter D: "Have you tried to disconnect the battery and let the ECM/TCM 'forget' its adaptive learning?" *******************************************
As a matter of fact, yes -- by coincidence it just got a new battery. It made no difference in the shiffting at all. Vehicle has about 155K on it.
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burboun supreme wrote:

What rear gears does it have? What rpm is it shifting at? If it is the HD version and was set up for heavy duty use the shifting may be normal. Higher gears will make it need more rpm before it shifts. Not much you can do unless you want to change out the front and rear gear sets.
--
Steve W.

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Steve W wrote: "What rear gears does it have? What rpm is it shifting at? If it is the HD version and was set up for heavy duty use the shifting may be normal. Higher gears will make it need more rpm before it shifts. Not much you can do unless you want to change out the front and rear gear sets." ********************************** I don't know what the rear gear ratio is on this vehicle. The wheels are 6 bolt. At 55 mph on the highway, the engine's just loafing along at about 1650 rpm's. When I take off from a stop sign with very light throttle, it will _still_ stay in first gear well past 2000 rpm. Because of this, I have taken to kind of really stepping into it from a stop to get it up to speed quickly -- and then letting off the throttle, at which point it goes into second, then the same for third... which isn't really even that big a deal but pretty annoying. Probably not too economical either :-) I thought (hoped) maybe the ECM controlled this somehow and it could be modified that way, rather than something internal. In any case, what controls the shift points on these -- the controller, or a governor or modulator, etc inside the trans?
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burboun supreme wrote:

Well the ECM controls most of the transmission functions. BUT you need some specific equipment to alter the program. Not really a DIY thing. You could take it in and see what the computer shows.
To determine the gearing look at the RPO tag in the glove box. It will tell you what options and what the drive train is set up for. The ratio codes usually start with GU or GT with a third letter/number. Post that OR have a dealer run your VIN. Either way you can get the ratio.
--
Steve W.

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burboun supreme wrote:

Well the ECM controls most of the transmission functions. BUT you need some specific equipment to alter the program. Not really a DIY thing. You could take it in and see what the computer shows.
To determine the gearing look at the RPO tag in the glove box. It will tell you what options and what the drive train is set up for. The ratio codes usually start with GU or GT with a third letter/number. Post that OR have a dealer run your VIN. Either way you can get the ratio.
--
Steve W.

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