Hit a Bump, Now I'm Stumped!

Hello! First post here, as it came out of necessity. I'll get around to an introduction when I can.

I have a '95 Caprice Wagon as my first car, towing package, with about 125,000 miles and a claimed 85,000 on the motor. A few days ago, I was accelerating in first gear at about 30 MPH and I hit a pretty nasty bump in the road. I immediately noticed a change in how the transmission shifted: it felt "disconnected" in a sense, with a sort of catch point, and the shifting seemed late. There was also a slight rattling, but it was rather quiet and stopped. From further driving I've discovered that the transmission will no longer shift from first to second with consistent throttle (not necessarily WOT); it only shifts if I let off and will hit the rev limiter otherwise.  First gear may feel a bit different, second gear seems nonexistent, third is fine, I think(?) fourth gear is engaging, although I haven't really been at speed enough to test it, and reverse is healthy. I studied the transmission sticky, but it doesn't seem to entirely match up with any one thing, and how could this all happen from hitting one bump? The last odd thing is that typically it would only downshift into first below 30 MPH, but now it will do it much later. To recap:

Cause: Hit a bump in 1st @ 30MPH

First: Could be slipping, but I've never felt slip before.
Second: Totally gone from what I can tell
Third: Normal
Fourth: Seems to be there, not 100% sure
Reverse: Normal
Shifting: No 1-2 shift until releasing throttle; will downshift into first at unusually high speed (before: 30, after: 40+)

Until now I've never had issues with the transmission except for a couple of weird things, like how the VSS shows up to 4-8mph if revving in park but is otherwise fine, and being stuck in 2-3 only once after having battery issues.

I know it's a long post, but I'm scared of extensive damage! Any help and advice is appreciated, and I'll be scanning/inspecting it next week. Thanks!

Any sign of transmission fluid leaks under the car?

sherlock9c1 wrote:

Any sign of transmission fluid leaks under the car?

Not that I can see. Level appears to not have changed either.

The electrical connector may be loose, or coincidentally a wire may have broken, or been cut. It is going to take a good bit of troubleshooting to find the culprit. This is probably far beyond the ability to troubleshoot without hands on.

Fred Kiehl wrote:

The electrical connector may be loose, or coincidentally a wire may have broken, or been cut. It is going to take a good bit of troubleshooting to find the culprit. This is probably far beyond the ability to troubleshoot without hands on.

Damn. Sounds like it'll be "fun". An electrical connector being loose or broken sounds way better than something like a broken sunshell that'd require rebuilding/replacing the whole thing, though. In the meantime, babying it's probably the way to go, yeah?

I would not drive it any more than is absolutely necessary (only if you are driving to a transmission shop). Driving it may cause internal damage. If you can not diagnose, and fix it yourself, you should take it to a reputable transmission shop. The loose electrical connection is only a SWAG. Your trans is electronically controlled, so could be malfunctioning because of non mechanical issues.

If you don't already have an ALDL cable, I would highly suggest investing in or making one. I did a short write up on here on how to make one. One super helpful tool I found is Scan9495, which is free to use. You can manually command which gear you want the trans to hold from there. For example, you can hold the trans in 3rd, then command 4th and confirm whether the trans is shifting properly.

It would be wise to pull the pan before digging too deep. It is probably time for a filter anyway. If your 2nd band is worn, you should see plenty of debris in the pan. 2nd band is responsible for both 2nd and 4th.

As far as the bump, check wires like fred said. You could manually check via an multimeter that all the internal wires are good.

Start with checking if 4th is truely holding, and by pulling the pan, and report back