Help! '84 transmission info please.

[roger longman]

Driving my son's '84 vette 4 years ago I found one of the most noticable differences to be the harshness of the auto trans,particularly when you are about to stop,compared to my '88.Last year he had the box completely rebuilt. I drove it last week following his complaint that he was only getting 11mpg! I thought it was much worse than the original. Driving "normally"not quick), to me,it stayed in a gear way too longand really clonked when moving from park into drive, the changes were also much harsher. my thought to him was that he had gotten used to the deterioration over time.He went back to the shop and was told this was how the factory designed it in '84. Can anyone please tell me what is wrong,I looked in the manual which said it could be the throttle valve cable. Thank you in advance.

 

[roger longman]

'84 vette transmission

can no one help me with this?

 

[minifridge1138]

It does sound like the TV cable is not adjusted correctly.

If you have the manual, follow its instructions to reset it and let it self adjust.

I'm not sure what you mean by "clonked when moving from park into drive" but the TV cable would cause it to shift too late or too early.

 

[roger longman]

thanks

thanks minifridge will follow manuals instructions.

 

[Hib Halverson]

One thing that's difficult with trying to fix a problem like this via the Internet is subjective evaluation. A "hard" shift to someone used to driving an old Cadillac will be a normal shift to somone used to driving a new Corvette.

That said, if the TV cable is not adjusted properly or there is some other problem with the trans, the result can be a really aggressive shift.

One thing you can do is obtain a factory service manual and look up the diagnostic information for hard shifting. That may help you decide if there's a problem or not.

 

[roger longman]

I take your point hib but my main contention is that I find the transmission to be worse now that it has been "proffesionally" rebuilt. Roger.

 

[xrcrx]

My first guess would also be a misadjusted TV cable. That can cause it to hang in gear too long. The firm shift is probably a bit harsh due to the hang up, but it will probably, and should retain a firm, positive shift action when properly adjusted.

 

[JohnGrawcock]

Keep an eye on the tach and count the gear changes. You may not be getting into high gear at all. If you are you should be able to cruse at a steady 60 or 65 MPH with fuel mileage in the upper twenties to low thirties. On the bottom end when accelerating gradually at low speeds an 84 will normally shift at a lower RPM than most. The power band on that engine is like 1000 to 4500 RPM. The factory shift points were lower than usual to take advantage of that fact.

As others have said, it sounds like a tv cable problem. If the adjustment procedure in the manual doesn't fix it check to see if the cable is broken. The upper end of the cable (the part with the adjustment button) should be molded to the cable sheath. The sheath can get broken away from the upper end and the extra slack prevents proper adjustment.

 

[killain]

Driving my son's '84 vette 4 years ago I found one of the most noticable differences to be the harshness of the auto trans,particularly when you are about to stop,compared to my '88.Last year he had the box completely rebuilt. I drove it last week following his complaint that he was only getting 11mpg! I thought it was much worse than the original. Driving "normally"not quick), to me,it stayed in a gear way too longand really clonked when moving from park into drive, the changes were also much harsher. my thought to him was that he had gotten used to the deterioration over time.He went back to the shop and was told this was how the factory designed it in '84. Can anyone please tell me what is wrong,I looked in the manual which said it could be the throttle valve cable. Thank you in advance.

My 84 did the same kind of behavior til I took out the old ecm chip, and installed a 'Hypertech Street chip' in the ecm. It stopped the extended shifts, which are there to help with gas milage by getting you into top gear as fast as possible. It also smoothed out the shifting patten. My $0.02

 

[Hib Halverson]

I take your point hib but my main contention is that I find the transmission to be worse now that it has been "proffesionally" rebuilt. Roger.

If you feel the transmission is worse now that it's been "professionally" rebuilt, then it seems to me your choices are clear:

1) Some of the suggestioned offered above related to the TV cable adjustement are good advice. Beyond that, if you want to continue to work towards a DIY solution, gain enough knowledge and experience with the Turbo-Hydramatic 700R4 to diagnose and repair it yourself.

2) Be willing to take the next steps with the original service shop, ie: go bak to them and ask them to properly repair the trans, or go to arbitration or file a law suit.

3) Take the car to a different, more "professional" service shop and have the transmission repaired correctly.