SL2 Tranny Problem PLEASE HELP

[dcg9981]

I had a 1997 SL1 SOHC that had a bad rod bearing and I bought a 1997 SL2 DOHC witha bad tranny, i called the dealership and they said the only difference was the final drive ratio, on the two automatic transmissions used in this car, I did the installation, the car runs great, until it shifts out of 1st gear then the rpm's rev up and you have to slow down before the trans re-engages, it doesn't matter if you floor it or grandma it through first, still the same result, please help with any ideas, i dont see anything unplugged and the tranny worked fine 2 days ago.you can email me here or on my private email, [email protected]

[dcg9981]

are the transmissions from a 1997 sohc and a 1997 dohc (automatic) the same and can they be swapedopcorn:

[dcg9981]

If you use a different automatic trans than what came in the vehicle I was told that you have to go to the dealership and get the computer flashed to that transmission because of the different gearing, the computer gets confused and wont shift correctly, does this sound right to anyone, please give some feed back.

[sierrap615]

umm....using a transmission from a SOHC engine with a DOHC engine will lead to problems...yes they bolt up fine but the different gear ratios is the problem. the PCM(powertrain control module) has the gear ratios programed into it, if the PCM detects the wrong gear ratio, it will assume the tranmission is slipping and default to limp mode. i beleave only 1st and reverse have the same gears between the SOHC and DOHC verisons of the transmission. 2nd, 3rd, and 4th are different. source: http://www.differentracing.com/tech_...gearratio.html

using the DOHC PCM with the SOHC transmisson should result in limp mode.

using the SOHC PCM with the DOHC engine means you will be using the wrong fuel maps and should result in, if nothing else, poor perfromance.

lets assume i'm wrong about the engine/transmission/PCM missmatch. there would be two other things i would look into. the first is double checking the fluid level. the second is a loose input shaft nut, it is a common problem with that transmission and can cause trouble shifting, commonly related to a slam. but i beleave that it is something that fails slowly over time, not in two days. and the only diagnosis i know of for the nut is remove the end cover and check it.

i suggest researching on the Saturnfans.com forums.

[sierrap615]

I just saw you three threads about the same issue. I am merging them together to keep the forum tidy.

flashing is not an option here, Saturn only releases programing for stock engine/trans combinations(DOHC eng/DOHC trans or SOHC eng/SOHC trans), they do not offer missmatched combos(DOHC eng/SOHC trans or SOHC eng/DOHC trans)