4L70E shift problems
07-08-2015, 04:48 PM
#1
Staging Lane
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4L70E shift problems
Hello all,
I have had several transmission problems in my years but this one beats all. I have 2 trucks. 2001 GMC 1500 5.3 with the 4L60E, and a 2007 silverado MAX 1500 with the 6.0 and the 4L70E.
Problem #1.
The 4L60E clutches went out a few times. The obvious was it wouldn't go anywhere..lol and tac out. Had it rebuilt. Has about 10,000 miles on it now. Runs good, no slip, up to the point trans temp hits 195. Once temp hits 195 it starts to slip. You can watch the tac start jumping up a little and also feel it. And know when you throttle its slipping. But when it cools back down you can floor it in all gears and its fine up until it warms back up.
Problem #2.
2007 Silverado MAX 4L70E.
This one I have one idea for the problem but have not attempted to do anything yet as I will explain.
I can floor this truck and boil the tires off of it, then when shift to 2nd....there is no second. Just tacs out. I can let off and third will catch and I have third. I can ride third gear half throttle so it wont down shift to second because there is no second up until I run out of road. I mean it will flat out fly over 115 easy....but wont shift into 4th or overdrive.
So.....1st but no 2nd hookup, shifts to second but tacs out not catching and 3rd but wont even shift into 4th.
I was thinking it was not forward clutch because I have such a strong 1 and 3rd. But can not explain a total slipping 2nd. Bringing me to question
a. if it may be the a&b solenoid?
b. the piston accumulator?
I have read that the pistons X 2, 1-2 and 3-4, are pinned plastic and fail because of leakage and people going to the aluminum pin less. Would it cause no shift? or a slipping 2nd? I dont know. Would the a/b solenoid be the culprit? I dont know without just changing parts.
But would really just want to know if I am barking up the wrong tree all together.
Worst case scenario I will have to pull it and bring it to get total rebuild. I was just trying, like everyone else, to avoid the pull. Only reason once again was because I have questions about having a strong 1st and 3rd like nothing is wrong. Unlike every other trans I have burnt up that just slips in every gear and eventually just quits pulling. And I have probably burnt clutches in close to 35 or more. But I have never had this kind of problem on either one truck that are going on right now.
Thanks for any input.
Respectfully,
Rooster
I have had several transmission problems in my years but this one beats all. I have 2 trucks. 2001 GMC 1500 5.3 with the 4L60E, and a 2007 silverado MAX 1500 with the 6.0 and the 4L70E.
Problem #1.
The 4L60E clutches went out a few times. The obvious was it wouldn't go anywhere..lol and tac out. Had it rebuilt. Has about 10,000 miles on it now. Runs good, no slip, up to the point trans temp hits 195. Once temp hits 195 it starts to slip. You can watch the tac start jumping up a little and also feel it. And know when you throttle its slipping. But when it cools back down you can floor it in all gears and its fine up until it warms back up.
Problem #2.
2007 Silverado MAX 4L70E.
This one I have one idea for the problem but have not attempted to do anything yet as I will explain.
I can floor this truck and boil the tires off of it, then when shift to 2nd....there is no second. Just tacs out. I can let off and third will catch and I have third. I can ride third gear half throttle so it wont down shift to second because there is no second up until I run out of road. I mean it will flat out fly over 115 easy....but wont shift into 4th or overdrive.
So.....1st but no 2nd hookup, shifts to second but tacs out not catching and 3rd but wont even shift into 4th.
I was thinking it was not forward clutch because I have such a strong 1 and 3rd. But can not explain a total slipping 2nd. Bringing me to question
a. if it may be the a&b solenoid?
b. the piston accumulator?
I have read that the pistons X 2, 1-2 and 3-4, are pinned plastic and fail because of leakage and people going to the aluminum pin less. Would it cause no shift? or a slipping 2nd? I dont know. Would the a/b solenoid be the culprit? I dont know without just changing parts.
But would really just want to know if I am barking up the wrong tree all together.
Worst case scenario I will have to pull it and bring it to get total rebuild. I was just trying, like everyone else, to avoid the pull. Only reason once again was because I have questions about having a strong 1st and 3rd like nothing is wrong. Unlike every other trans I have burnt up that just slips in every gear and eventually just quits pulling. And I have probably burnt clutches in close to 35 or more. But I have never had this kind of problem on either one truck that are going on right now.
Thanks for any input.
Respectfully,
Rooster
Last edited by ferrellrooster; 07-08-2015 at 08:17 PM.
07-12-2015, 12:26 PM
#3
Teching In
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How did your trans workout? I'm installing a superior trans shift correction kit along with the pinless accumulators as I'm writing this. I was curious if the stiffer springs could be installed with these Pistons?
07-12-2015, 06:11 PM
#4
The band is used for both second and fourth. There's a fairly easy way to tell if the band is smoked in a 60/65/70. Get the truck in the air enough to get under it, make sure it's in park and let the engine idle. Crawl under and use a pry bar to apply force to the servo cover on the passenger side. (you may need to remove a heat shield to get to it). The engine should bog noticeably when you do this. If that has no effect it could mean the band is burnt up. If it does bog you can focus on a hydraulics problem.
07-13-2015, 09:45 AM
#5
Staging Lane
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The band is used for both second and fourth. There's a fairly easy way to tell if the band is smoked in a 60/65/70. Get the truck in the air enough to get under it, make sure it's in park and let the engine idle. Crawl under and use a pry bar to apply force to the servo cover on the passenger side. (you may need to remove a heat shield to get to it). The engine should bog noticeably when you do this. If that has no effect it could mean the band is burnt up. If it does bog you can focus on a hydraulics problem.
I thought I could get pan off without dropping exhaust but that was a big hell no. Drained most all the fluid. My 2001 is all 15mm exhaust bolts. This 2007 has 2 different sizes 15 & 17mm. I broke/split a deep well trying to get it off even with heat, so I have to go to store today after work to get some impact quality 6 points. Should know something in a day or so after I put the new accumulators in.
After knowing this trick you shared I feel like Im working backwards. lol
07-13-2015, 09:53 AM
#6
Staging Lane
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The band is used for both second and fourth. There's a fairly easy way to tell if the band is smoked in a 60/65/70. Get the truck in the air enough to get under it, make sure it's in park and let the engine idle. Crawl under and use a pry bar to apply force to the servo cover on the passenger side. (you may need to remove a heat shield to get to it). The engine should bog noticeably when you do this. If that has no effect it could mean the band is burnt up. If it does bog you can focus on a hydraulics problem.
It is shifting to 2nd but just tachs out, shifts to 3rd runs great, but does not shift at all to 4th. 1st is strong, 3rd is strong and tight.
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