Need Help: 4+3 Transmission
Thread Starter
Instructor
Joined: May 2006
Posts: 178
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From: peachtree city
Need Help: 4+3 Transmission
I just bought an 88 with the 4+3 transmission. When i'm at cruise, and I get on the throttle the clutch slips (the rpms spike). The clutch pedal feels normal. Any ideas on what would could cause this?
Thanks
Thanks
Melting Slicks
Joined: Aug 2003
Posts: 3,401
Likes: 397
From: Lakeville MI
Are you familiar with the operation of the 4+3?
If not, here is a good reference table:
http://www.5speeds.com/43table.htm
What you have described could simply be an automatic downshift due to throttle input if od was previously active.
You didn't mention whether od was on, off, active, or inactive or which gear you were in when this ocurrs. Please be specific.
Of course it could also be a slipping clutch or slipping o/d clutch.
The more info you can provide, the better the responses you will receive.
If not, here is a good reference table:
http://www.5speeds.com/43table.htm
What you have described could simply be an automatic downshift due to throttle input if od was previously active.
You didn't mention whether od was on, off, active, or inactive or which gear you were in when this ocurrs. Please be specific.
Of course it could also be a slipping clutch or slipping o/d clutch.
The more info you can provide, the better the responses you will receive.
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Does the same thing happen regardless of whether or not you are using the OD?
The OD unit will kick down (go out of OD) with 75% throttle and RPM is below 2500. This is the case in 2nd, 3rd, and 4th gears with the OD engaged. This should feel very much like the kickdown with an automatic tranny.
If the RMP incerease is gradual with only a light increase in throttle, the chances are the clutch disc is worn. Do you get any gear grinding when going into reverse? That's usually the best indication of a worn clutch.
The clutch is hydraulically operated and unless there is air in the system, you should not feel anything different in the pedal even if the clutch is worn. There is no adjustment in the clutch.
The OD unit will kick down (go out of OD) with 75% throttle and RPM is below 2500. This is the case in 2nd, 3rd, and 4th gears with the OD engaged. This should feel very much like the kickdown with an automatic tranny.
If the RMP incerease is gradual with only a light increase in throttle, the chances are the clutch disc is worn. Do you get any gear grinding when going into reverse? That's usually the best indication of a worn clutch.
The clutch is hydraulically operated and unless there is air in the system, you should not feel anything different in the pedal even if the clutch is worn. There is no adjustment in the clutch.
Thread Starter
Instructor
Joined: May 2006
Posts: 178
Likes: 0
From: peachtree city
Sounds like I have a worn clutch. The slippage occurs with the overdrive on or off. The rpm increases whenever the gas pedal is punched hard and before the car begins to accelerate. Normal acceleration and shifting is fine, and no problems noticed in reverse. I guess the hydraulic clutch explains why the pedal play feels normal. I was hoping the fix would be just an adjustment. Thanks for the info.
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Yes, sounds like the clutch. It will happen more in the higher gears since the clutch usually transmits more torque there during normal driving than in the lower gears.
