4L60E lost 4th.
Thread Starter
Registered User
Joined: Jun 2024
Posts: 1
Likes: 0
4L60E lost 4th. Lost 4th gear but it works fine otherwise. Less than 300 miles on it and it worked fine till after l got back from camping. There is no codes and fluid is full and new. It will work when I first start up and drive but after 3 miles it downshifts to 3rd. Please help me 🙏
Last edited by Handyman88; Jun 12, 2024 at 12:39 AM. Reason: Additional information
LS1Tech Sponsor
Joined: Mar 2023
Posts: 1,824
Likes: 1,162
From: BERWICK PA
Thing is to figure out what it is actually doing? Is it a downshift to 3rd or lockup stops, Is it a commanded downshift ? Look at data. If it loose 4th or lockup and is not a commanded function it should be setting a code.
Also note and its not a cut on the servo but I have helped a couple people "not my builds though easily could have been" who started slipping in 4th to find the seals in in the servo had gotten hard and crumbled. Reason not faulty seals or servo but exhaust proximity. The 4th servo is a dead end flow so no cooling once full and driving in 4th , The exhaust actually catalytic converter literally heated the servo the point is rapidly broke down the seals,
If running the sonnax 4th (best of the aftermarket 4th servos IMO) and proximity is very close to exhaust or particular the catalytic converter a heat shield which many leave off is a MUST . This is not really an issue with the stock servos as the teflon seals are much more durable when it comes to heat,
But I would first use a data scan to see what you are actually losing Lockup or 4th and if it's commanded or not. In either case if its losing and its not commanded and codes have not been disabled in tune it should be setting a code.
Figure out what and how then we can look for the why.
Also note and its not a cut on the servo but I have helped a couple people "not my builds though easily could have been" who started slipping in 4th to find the seals in in the servo had gotten hard and crumbled. Reason not faulty seals or servo but exhaust proximity. The 4th servo is a dead end flow so no cooling once full and driving in 4th , The exhaust actually catalytic converter literally heated the servo the point is rapidly broke down the seals,
If running the sonnax 4th (best of the aftermarket 4th servos IMO) and proximity is very close to exhaust or particular the catalytic converter a heat shield which many leave off is a MUST . This is not really an issue with the stock servos as the teflon seals are much more durable when it comes to heat,
But I would first use a data scan to see what you are actually losing Lockup or 4th and if it's commanded or not. In either case if its losing and its not commanded and codes have not been disabled in tune it should be setting a code.
Figure out what and how then we can look for the why.
__________________
Frank formerly of Performabuilt, Now just me, What can I build for you today? Call or message me. Click sig pic for my facebook
Frank formerly of Performabuilt, Now just me, What can I build for you today? Call or message me. Click sig pic for my facebook
