Strange problem with 4+3

[steveb]

The vette in question is a 1985 4+3 with about 33000 miles. I have been noticing a strange problem every so often when I shift into reverse. While backing out, it is as if something is locking up. It is literally like trying to back up with the emergency brake on. This happens very seldom. Most of the time it reverses as it should.

I have searched through previous posts on problems with the 4+3 overdrive. It appears that the overdrive is toast when the transmission starts slipping in reverse. However, the problem does not seem to be with slipping in reverse so I am not sure that the overdrive is to blame. The overdrive appears to function properly and engage when it should.

I was wondering if anybody had any tips or ideas on things to look for. Something does not seem right and I am not sure where to start looking.

Thanks in advance.

Steve

 

[rwd]

I'm not clear on how the problem manifests itself. Do you mean that the car sticks initially when you let out the clutch and then rolls freely, or that there is a continual mild drag that does not dissipate? Sometimes, the brakes will freeze, for example, if the car is washed and then parked for a period of time.

More info (sounds?) might give somebody else an idea, but I'd be surprised if the overdrive unit were involved.

 

[steveb]

There is a continual mild drag that does not dissipate. Once I go to a forward gear and then back to reverse the problem seems to disappear. The last time this happened, I spent about 5 minutes going back and forth in my driveway trying to get it to do it again and it wouldn't. Something does not seem right but I am not sure where to begin looking. Might be the beginning stages of something failing. Since the overdrive seems to work ok and there are no strange noises coming from the tranny, I think I can rule that out.

Thanks for your reply rwd.

Steve

 

[rrubel]

Do you use your parking brake at all? Our years are notorious for parking brake problems because the cables and other moving parts are all low to the ground, exposed to the elements. Is it possible that the brake shoe has shifted and is binding?
[RICHR]

 

[steveb]

I do use the parking brake on occasion. I'll try to check that out this weekend. Thanks for replying.

Steve

 

[rwd]

I had an '85 4+3 for a long time with similar mileage, and I never had that particular experience. I'd tend to lean toward something like the braking system or parking brake, but that's just a guess. There's always the possibility a caliper/piston is dragging slightly and releases when you brake the car to a stop. That's more likely to happen when the pads get thin and the pistons get extended further out.

It might be worth checking for brake fluid leaks on the calipers or inside the wheels and also looking at the master cylinder level. If you've ever gotten a warning light on the brake system that might be relevant to an intermittent master cylinder problem. The parking brake can definitely hang up and not release, however, even if the light says otherwise.

Good luck. If I get any other ideas, I'll let you know.

 

[steveb]

I really appreciate all of the replies. I think I will give the brake system a good going over this weekend. When it happens, it does act as if the parking brake were on. I am glad to be able to rule out the overdrive.

Thanks,

Steve

 

[GusVette]

I never had that problem with my 85' 4+3. Had everything else on the trans and od fail though. I'd go with the brake binding advice also.
Good Luck,
Gus