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I got a call today on a 98 Montana that needs a transmission. (Customer diagnosis...LOL...not a good start)
So I picked it up and drove it to the shop and here's what it's doing...
You put it in drive and it takes off like nothings wrong. When it's time to shift to second it acts as though it goes into neutral and will not shift until you lift on the throttle. It's not a typical slipping between gears. When you lift on the throttle it shifts normally until it's time to go into the next gear. I did notice that if you are really babying it from a take off it'll shift without slippage sometimes. For the most part even when going really easy on it it'll do the same thing.
It will not shift no matter how long you wait. Until you lift on the throttle, it won't shift.
Also, it will do this when you step on the throttle hard enough to engage the passing gear. It downshifts, then acts like it goes into neutral, you lift, it shifts. Or, it just stays in the lower gear until you lift. I think it did that once. I didn't drive it far, about maybe 10 miles.
The check engine light is on so I scanned it to see if there were any powertrain related codes.
Mostly missfire, lean on one bank intermittent, and catalyst.
But one code is P0122 which is the Throttle Position Sesnor code.
That's the only one that made me question anything.
Is there any possibility that the TPS issue could made the transmission act like that?
I wouldn't think so but you never know.
I have no problem dropping the trans and swapping it for him. I'd just kinda like to know for sure the transmission is actually bad and not some electronic part on it that can be diagnosed.
I'd just assume not have to go through all the hassle of changing the trans if I can avoid it.
I honestly don't know enough about this transmission to know where to start as far as diagnosis beyond scanning for codes. I could check line pressure I suppose, I could drop the pan to see if there's friction mud in it. I also don't want to do a bunch of diagnosis for free either. When the customer does a self diagnosis and you question and are right, it's great. And you can bill for it. If you're wrong and you need to r and r it anyway, the diagnosis is free. I would prefer to not deal with people who can diagnose but not fix but this customer supplies me with the vast majority of my work. Tricky situation.
Any help would be greatly appreciated,
Thanks in advance,
Wayne
So I picked it up and drove it to the shop and here's what it's doing...
You put it in drive and it takes off like nothings wrong. When it's time to shift to second it acts as though it goes into neutral and will not shift until you lift on the throttle. It's not a typical slipping between gears. When you lift on the throttle it shifts normally until it's time to go into the next gear. I did notice that if you are really babying it from a take off it'll shift without slippage sometimes. For the most part even when going really easy on it it'll do the same thing.
It will not shift no matter how long you wait. Until you lift on the throttle, it won't shift.
Also, it will do this when you step on the throttle hard enough to engage the passing gear. It downshifts, then acts like it goes into neutral, you lift, it shifts. Or, it just stays in the lower gear until you lift. I think it did that once. I didn't drive it far, about maybe 10 miles.
The check engine light is on so I scanned it to see if there were any powertrain related codes.
Mostly missfire, lean on one bank intermittent, and catalyst.
But one code is P0122 which is the Throttle Position Sesnor code.
That's the only one that made me question anything.
Is there any possibility that the TPS issue could made the transmission act like that?
I wouldn't think so but you never know.
I have no problem dropping the trans and swapping it for him. I'd just kinda like to know for sure the transmission is actually bad and not some electronic part on it that can be diagnosed.
I'd just assume not have to go through all the hassle of changing the trans if I can avoid it.
I honestly don't know enough about this transmission to know where to start as far as diagnosis beyond scanning for codes. I could check line pressure I suppose, I could drop the pan to see if there's friction mud in it. I also don't want to do a bunch of diagnosis for free either. When the customer does a self diagnosis and you question and are right, it's great. And you can bill for it. If you're wrong and you need to r and r it anyway, the diagnosis is free. I would prefer to not deal with people who can diagnose but not fix but this customer supplies me with the vast majority of my work. Tricky situation.
Any help would be greatly appreciated,
Thanks in advance,
Wayne
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