I recently installed a rebuilt trans ( trangso shiftkit, vett servos, bw clutches, etc...) w/ a yank 3600 tc and now it vibrates only in 4th gear. TV is adjusted, no loose connections, drive/prop shaft are installed properly, everything seems tight. The trans is a lil overfilled but im not sure if that'll have anything to do with it. Any help would be appreciated. Thanks
Vibration only in 4th gear
- Thread starter mickeyj36
- Start date
George Blake
DONATING MEMBER
Re: Vibration only in 4th gear
You need to troubleshoot.
Check road speed where vibration starts.
Try the SAME road speed in 3rd and 4th.
Some 700s are set up so they ONLY lock up in 4th.
If that is the case, unlock the converter in 4th and see if it goes away. If it does, you may be locking up too early or you have a tuning issue that creating the shudder. When the converter is locked up, a much greater load is placed on the engine. If you are shifting into 4th too soon, the engine will lug, creating a shudder. Many things to consider. If this doesn't make any sense, take it to a transmission shop and let them trouble shoot it to see what the real problem is.
You need to troubleshoot.
Check road speed where vibration starts.
Try the SAME road speed in 3rd and 4th.
Some 700s are set up so they ONLY lock up in 4th.
If that is the case, unlock the converter in 4th and see if it goes away. If it does, you may be locking up too early or you have a tuning issue that creating the shudder. When the converter is locked up, a much greater load is placed on the engine. If you are shifting into 4th too soon, the engine will lug, creating a shudder. Many things to consider. If this doesn't make any sense, take it to a transmission shop and let them trouble shoot it to see what the real problem is.
NJ93TY
Donating Member
Re: Vibration only in 4th gear
Are you feeling engine vibration or drivetrain vibration? Once the convertor is in lockup and if you were to have a light misfire it may feel as the transmission is vibrating or something in the drivetrain. Try to narrow down where the vibration is.
Are you feeling engine vibration or drivetrain vibration? Once the convertor is in lockup and if you were to have a light misfire it may feel as the transmission is vibrating or something in the drivetrain. Try to narrow down where the vibration is.
Re: Vibration only in 4th gear
Yea it's a transmission vibration only in 4th gear. It doesn't matter what speed im at. Once the trans engages into 4th, the vibration occurs. If I drive with OD OFF the vibration is gone.
George Blake- I'll try unlocking the tc in 4th and let you guys know whats going on.
Thanks
Yea it's a transmission vibration only in 4th gear. It doesn't matter what speed im at. Once the trans engages into 4th, the vibration occurs. If I drive with OD OFF the vibration is gone.
George Blake- I'll try unlocking the tc in 4th and let you guys know whats going on.
Thanks
NJ93TY
Donating Member
Re: Vibration only in 4th gear
What happens when you put it nuetral??[/QUOTE]
I read a post on here a while back saying you should NOT put the trans in neutral while moving above a certain speed. I wouldnt suggest that.
Here it is, post # 23
http://www.syty.net/forums/showthread.php?t=58460&page=1&pp=15
What happens when you put it nuetral??[/QUOTE]
I read a post on here a while back saying you should NOT put the trans in neutral while moving above a certain speed. I wouldnt suggest that.
Here it is, post # 23
http://www.syty.net/forums/showthread.php?t=58460&page=1&pp=15
George Blake
DONATING MEMBER
Re: Vibration only in 4th gear
I'm betting its a shudder load issue and not a trans issue. The reason I say that is when you go into 4th gear, the parts that WERE spinning are now not spinning. In other words, you have LESS components spinning now than you did before. 2nd gear has a lot of the same components being held and your not vibrating in 2nd. That make sense? You should be shifting into 4th at about 44MPH with part throttle. If you take a stick shift and shift it into too high of a gear too soon and you'll put a TON of load on the engine and it'll shudder like crap. With an automatic, you get the added stress of the converter lockup. If throttle position is too low, line pressure will be too low to hold the TCC if it's locking up too soon. Then you get the TCC shudder.
I'm betting its a shudder load issue and not a trans issue. The reason I say that is when you go into 4th gear, the parts that WERE spinning are now not spinning. In other words, you have LESS components spinning now than you did before. 2nd gear has a lot of the same components being held and your not vibrating in 2nd. That make sense? You should be shifting into 4th at about 44MPH with part throttle. If you take a stick shift and shift it into too high of a gear too soon and you'll put a TON of load on the engine and it'll shudder like crap. With an automatic, you get the added stress of the converter lockup. If throttle position is too low, line pressure will be too low to hold the TCC if it's locking up too soon. Then you get the TCC shudder.
midnightbluS10
Banned
Re: Vibration only in 4th gear
So if thats the case then does that mean i have nothing to worry about? I get what your saying and it does make sense but i just wanna be sure i dont break anything. IF it is a trans issue i got a 1 year warrenty so i'll be fine. The trans shifts around 42mph w/ prt throttle so its close to 44.
I also locked up the tc in 4th as u suggested and the vibration is still there. I haven't been able to floor cuz im still in the break in period so i can't really tell how it acts @ wot or 75% throttle. Also i forgot to mention that i also have a BM supercooler kit if that makes any difference. Thanks for the responses.
George Blake said:
So if thats the case then does that mean i have nothing to worry about? I get what your saying and it does make sense but i just wanna be sure i dont break anything. IF it is a trans issue i got a 1 year warrenty so i'll be fine. The trans shifts around 42mph w/ prt throttle so its close to 44.
I also locked up the tc in 4th as u suggested and the vibration is still there. I haven't been able to floor cuz im still in the break in period so i can't really tell how it acts @ wot or 75% throttle. Also i forgot to mention that i also have a BM supercooler kit if that makes any difference. Thanks for the responses.
George Blake
DONATING MEMBER
Re: Vibration only in 4th gear
UNLOCK the converter and see if it goes away. Not lock. You can just lightly press on the brake pedal. LIGHTLY. And it will unlock the converter. Keep your right foot on the gas. Your NOT applying the brake. Just enough pressure to engage the brake switch so the ecm turns off the TCC. Get your speed to 4th and the vibration area and just lay the foot on the brake to unlock it and see if the vibration goes away.mickeyj36 said:
Re: Vibration only in 4th gear
Update...The timing was off a lil so i timed it and well the truck ran ALOT better but the vibration is still there. It actually calmed down alot to where its not annoying so as long as there is no problems then im just gonna live with it.
Update...The timing was off a lil so i timed it and well the truck ran ALOT better but the vibration is still there. It actually calmed down alot to where its not annoying so as long as there is no problems then im just gonna live with it.