K2500 6.2 D 1993 4x4 with 4160 tranny shifting rough
July 2nd, 2020, 12:30 PM
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K2500 6.2 D 1993 4x4 with 4160 tranny shifting rough
Hi,
problem is that gear sifting is a rough event. When pressing gas pedal gently it's ok. But if some acceleration needed the word for sift is "sudden.." no softy softy just "bang" and gear is sifted (with every gear). New TPS sensor, setted roughly 0.6 V idle and 4.3 V on max. New oils in the tranny.
problem is that gear sifting is a rough event. When pressing gas pedal gently it's ok. But if some acceleration needed the word for sift is "sudden.." no softy softy just "bang" and gear is sifted (with every gear). New TPS sensor, setted roughly 0.6 V idle and 4.3 V on max. New oils in the tranny.
July 4th, 2020, 3:16 PM
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Did the hard shifting start before or after the fluid change? What was the condition of the old fluid? Did you see any splinter size or larger particles in it? What about black, gritty material?
Is it only a hard shift if you’re already in motion or does it shift hard when you select the gear (shifting from reverse to drive, for example)?
Is it only a hard shift if you’re already in motion or does it shift hard when you select the gear (shifting from reverse to drive, for example)?
July 4th, 2020, 4:01 PM
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Did the hard shifting start before or after the fluid change? What was the condition of the old fluid? Did you see any splinter size or larger particles in it? What about black, gritty material?
Is it only a hard shift if you’re already in motion or does it shift hard when you select the gear (shifting from reverse to drive, for example)?
Is it only a hard shift if you’re already in motion or does it shift hard when you select the gear (shifting from reverse to drive, for example)?
I bought the truck roughly four months ago. First thing was that I changed all fluids and filters. The tranny pan was actually quite clean. No particles nor that sticky black stuff. Oil was dark red but didn't smell burned. So I really can't say was the problem before the oil change.
Hard shifting is when the truck is in motion. If I pull out gently from the lights it's quite ok. But harder pedal pressing makes the shifts really nasty (not healty for the tranny not joints).
I lowered the idle rpm to get the TPS on range. By lowering the idle rpm the sifting from R to D came a lot smoother.
Could it be the oil? It has Dexron III (some German brand) on it but I heard the rumours that not every oil even with correct classification will work.
July 5th, 2020, 8:03 AM
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Hi Gumby 22,
I bought the truck roughly four months ago. First thing was that I changed all fluids and filters. The tranny pan was actually quite clean. No particles nor that sticky black stuff. Oil was dark red but didn't smell burned. So I really can't say was the problem before the oil change.
Hard shifting is when the truck is in motion. If I pull out gently from the lights it's quite ok. But harder pedal pressing makes the shifts really nasty (not healty for the tranny not joints).
I lowered the idle rpm to get the TPS on range. By lowering the idle rpm the sifting from R to D came a lot smoother.
Could it be the oil? It has Dexron III (some German brand) on it but I heard the rumours that not every oil even with correct classification will work.
I bought the truck roughly four months ago. First thing was that I changed all fluids and filters. The tranny pan was actually quite clean. No particles nor that sticky black stuff. Oil was dark red but didn't smell burned. So I really can't say was the problem before the oil change.
Hard shifting is when the truck is in motion. If I pull out gently from the lights it's quite ok. But harder pedal pressing makes the shifts really nasty (not healty for the tranny not joints).
I lowered the idle rpm to get the TPS on range. By lowering the idle rpm the sifting from R to D came a lot smoother.
Could it be the oil? It has Dexron III (some German brand) on it but I heard the rumours that not every oil even with correct classification will work.
It’s unusual that you didn’t find any debris in the pan - was the magnet clean?
It could be the oil - wouldn’t be the first time a knockoff product has been sold as the real thing - but if you decide to change it again, use Dexron VI or a quality synthetic fluid - GM recommends upgrading to Dex VI or equivalent for any trans using Dex V or earlier fluids. I’d recommend also doing a thorough flush by draining the pan (and torque converter if it has a drain plug), fill it up, go drive it, then repeat a drain and fill at least 2 more times to make sure the new fluid has fully circulated through the transmission, torque converter and cooler (if equipped).
July 5th, 2020, 10:44 AM
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When the hard shifts happen, are they sudden like the transmission is trying to shift normally, or is there a delay, meaning you can tell that it’s kicked out of one gear, but there’s a brief pause before it slams into the next gear?
It’s unusual that you didn’t find any debris in the pan - was the magnet clean?
It could be the oil - wouldn’t be the first time a knockoff product has been sold as the real thing - but if you decide to change it again, use Dexron VI or a quality synthetic fluid - GM recommends upgrading to Dex VI or equivalent for any trans using Dex V or earlier fluids. I’d recommend also doing a thorough flush by draining the pan (and torque converter if it has a drain plug), fill it up, go drive it, then repeat a drain and fill at least 2 more times to make sure the new fluid has fully circulated through the transmission, torque converter and cooler (if equipped).
It’s unusual that you didn’t find any debris in the pan - was the magnet clean?
It could be the oil - wouldn’t be the first time a knockoff product has been sold as the real thing - but if you decide to change it again, use Dexron VI or a quality synthetic fluid - GM recommends upgrading to Dex VI or equivalent for any trans using Dex V or earlier fluids. I’d recommend also doing a thorough flush by draining the pan (and torque converter if it has a drain plug), fill it up, go drive it, then repeat a drain and fill at least 2 more times to make sure the new fluid has fully circulated through the transmission, torque converter and cooler (if equipped).
it's like it wants to shift normally. The pan magnet was quite clean like the pan it self. There was no particles that you could feel with you fingers.
There is a drain hole in the pan. After changing the oil for the first time I changed the filter. After that I've flushed the system three times. I get roughly 3.5 Litres out per flush.
Just today I was driving and even I've dropped the idle rpm down putting the lever on R or D is not a "smooth" shift..
I'll flush the system with GM Dex VI and hope for the best. Bad sifting breaks my heart...
July 5th, 2020, 6:39 PM
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Have you tried checking for codes? They can be stored even though the CEL/SES light isn’t lit.
Also, what size tires are you running? Stock size is 245-75-16
Also, what size tires are you running? Stock size is 245-75-16
July 7th, 2020, 2:34 PM
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July 20th, 2020, 1:09 AM
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Hi Gumby22,
I flushed the tranny. Did not change the oil make though. It got better, but still the same problem. I took out the battery cables for a while (resetting the "brain".. don't know it helps) Also what came in to my mind was that the TPS-sensor I bought was a after market product (not GM). I try to buy often as possible GM parts but because I was desperate I fell in for the junk..
I flushed the tranny. Did not change the oil make though. It got better, but still the same problem. I took out the battery cables for a while (resetting the "brain".. don't know it helps) Also what came in to my mind was that the TPS-sensor I bought was a after market product (not GM). I try to buy often as possible GM parts but because I was desperate I fell in for the junk..
July 20th, 2020, 7:38 PM
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Hi Gumby22,
I flushed the tranny. Did not change the oil make though. It got better, but still the same problem. I took out the battery cables for a while (resetting the "brain".. don't know it helps) Also what came in to my mind was that the TPS-sensor I bought was a after market product (not GM). I try to buy often as possible GM parts but because I was desperate I fell in for the junk..
I flushed the tranny. Did not change the oil make though. It got better, but still the same problem. I took out the battery cables for a while (resetting the "brain".. don't know it helps) Also what came in to my mind was that the TPS-sensor I bought was a after market product (not GM). I try to buy often as possible GM parts but because I was desperate I fell in for the junk..
How are your skills with a multimeter?
I wouldn’t worry about the aftermarket TPS just yet (and honestly if it’s an SMP brand sensor, it’s a quality part) - there’s plenty of other electrical components to check before you get back to that.
Also, resetting the computer only goes so far. In 1993, adaptive controls were just being introduced - there was some capability for the PCM to learn shifting and driving patterns but it’s nowhere near what they are today. Additionally, some codes only set under specific conditions, and sometimes it takes those specific conditions 2 or 3 times before the CEL is requested, so resetting the PCM could actually be preventing the code you need from showing up.
It really shouldn’t matter, but what is the engine code (8th digit of VIN)? It should be either C or J for a 6.2 - I want to make sure I’m looking at the right wiring diagram.
July 21st, 2020, 12:32 PM
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If there wasn’t any real improvement with the fluid change, this is either a hard electrical fault or an internal mechanical problem. It could be a stuck valve in the valve body too, but before you start tearing that apart, focus on the electrical.
How are your skills with a multimeter?
I wouldn’t worry about the aftermarket TPS just yet (and honestly if it’s an SMP brand sensor, it’s a quality part) - there’s plenty of other electrical components to check before you get back to that.
Also, resetting the computer only goes so far. In 1993, adaptive controls were just being introduced - there was some capability for the PCM to learn shifting and driving patterns but it’s nowhere near what they are today. Additionally, some codes only set under specific conditions, and sometimes it takes those specific conditions 2 or 3 times before the CEL is requested, so resetting the PCM could actually be preventing the code you need from showing up.
It really shouldn’t matter, but what is the engine code (8th digit of VIN)? It should be either C or J for a 6.2 - I want to make sure I’m looking at the right wiring diagram.
How are your skills with a multimeter?
I wouldn’t worry about the aftermarket TPS just yet (and honestly if it’s an SMP brand sensor, it’s a quality part) - there’s plenty of other electrical components to check before you get back to that.
Also, resetting the computer only goes so far. In 1993, adaptive controls were just being introduced - there was some capability for the PCM to learn shifting and driving patterns but it’s nowhere near what they are today. Additionally, some codes only set under specific conditions, and sometimes it takes those specific conditions 2 or 3 times before the CEL is requested, so resetting the PCM could actually be preventing the code you need from showing up.
It really shouldn’t matter, but what is the engine code (8th digit of VIN)? It should be either C or J for a 6.2 - I want to make sure I’m looking at the right wiring diagram.
Yeah, that sounds good to check the electrical system first. I've played with small blocks and rear ends but trannys are big black hole for me.
I've been using the "Fluke" during these years while working with road construction equipment.
Ok, that's good to know. It was not cheap..
I checked the codes two weeks ago again with my trusty OBD "paper clip" reader. No codes (before I disconnected the battery).
The Win code for my truck is: 2GCFK29C6P1233067.