Please, I need help!!

[oreo]

I have a 94 Chevy Silverado 2WDr with a 350 (5.7 litre) engine. The transmission was not shifting properly when accelerating and I would have to let off the gas for it to shift without slamming into gear. Took it to SCAAMCO and their diagnosis was that it needed to be rebuilt and wanted $ 1600-$2000 to rebuild it.

So I decided that I would go to a junk yard and buy a used 4L60E tranny. I matched it as close as possible and took it to my mechanic to install. He installed it and the vehicle still has the same shifting problem, only not as severe.

My mechanic now tells me that it may be the Electronic Spark Control (ESC) that is in the distributor that may be the cause of the problem.

Can someone please confirm if this is the problem before I spend any moe $$$$.

Thanks in advance!!

[DanD]

Sorry I don’t know what to say, you know that two different transmissions are not likely to have the same problem. I don’t think the distributor can cause a transmission shifting problem but it may cause an engine running problem that may feel like a bad/hard shift. Due to a misfire or late timing but with the information all I’m doing is guessing.
Dan.

[oreo]

Dan,
Thanks for the reply!! I don't know if I should trust the mechanic and possibly spend another $200 on the ESC problem or not.

[DanD]

The 1-2 and 2-3 shifts with this transmission are electronically shifted through a pair of solenoids, which are controlled by the PCM. The PCM determines when to shift the trans not only by receiving inputs from the transmission sensors, but also from engine sensors.
So I guess I shouldn’t rule out the ESC, but there are a lot of other factors that could cause the PCM to hold a shift.
Is there any stored trouble codes in the PCM? Even if your check engine light has not come on, there could be pending codes that may give you a direction to look.
Has your mechanic had a look at scan data, for example the TPS output; it may be within it perimeters and not set a code but is constantly sending out either a low or high voltage. The computer would think it should hold off shifting the trans.
The same could go for the engine coolant temperature sensor, if the PCM thinks the engine is not up to temperature it will change shift patterns to accommodate the cold engine.
So talk to your mechanic and tell him your concerns and ideas, if he’s not sure of the cause, he should be willing to work with you to find the problem; it shouldn’t be sorry that didn’t fix it, here’s your bill.
Maybe reassure him that there’s no shame in saying I don’t know and ask him if he could recommend someone more familiar with the system.
I’m not trying to say anything about his abilities, but the days of one man that knows everything about a vehicle are long gone. Sometimes a fresh pair of eyes or a different approach will find the problem, believe me I’m not shy to pick up a phone to call for technical assistance or ask the guys here when I’m stuck.
Dan.