Transmission Shift Problems

[Erich]

Ever since i brought my high mileage 1991 LS400 home the trans never shifted correctly. During all the wet chicago weather one night my trans stopped shifting and R came on my cluster along with the actual trans mode i was in.

I was far from my shop and at a friends house at 2am..i worked on it until i fell asleep. Basically i TORE my trunk all apart exposed all wires looking for broken or loose. I was puzzled because everything was good and most oddly my reverse lights were also on. So i assumed there were no ground issues nor problems that everyone says is typical of the early. I came across a post talking about the PRNDL switch on the trans...anyhow. I went to grab my spare one off my spare engine and trans(i keep alot spare parts for my car) I went to take the 12mm nut off the bar and SNAP! I also managed to take the nut that keeps the switch on and broke that too. I stopped by a toyota dealer with my broken part off my trans to get a price $280 for the switch. I am like forget that, i salvage parts for a living and there are a bunch of C4C V8 cars in the yards. I pulled one of a 1994 SC400...the part was clean...12mm nut that holds the bracket came right off and i left the loosened nut on the switch on and pried it right off.

I get back to shop tonight to change oil and fix this. I used a torch to heat the nut up..tried that SNAP! The stud is actually very rusty. I actually can't believe Toyota uses such a small shaft. Its too fragile and was quite corroded. I pried the switch off and the rest of the shaft is quite corroded.

I notised the circuite coating plastic on back is cracking off the one i took my 100k spare trans, the SC400 one. The one off my 1991 with 270k miles was in very bad shape..you could see where water got in and it corroding, and it looked like it was melting.

I put the switch on from the SC400, plugged it in, bolted on...pushed the shift arm back on(No nut...very unsafe). Turn car on...problem GONE. Started it up..carefully put into gear(arm is not bolted on) and drove it...PROBLEMS GONE. Now this car randomly would not shift correctly for over 2 years... That appears to be resolved.

So for those people here that attack everyone when there R light is on the dash and trans is not shifting. You need to keep this in mind. I have a feeling this problem i have is prone to cars in the rust belt. Also if you try to take the nut off IT WILL SNAP. I will try to rework the arm to make it thinner and then put a new nut on it..there is some threads left. Otherise i need to take trans apart or replace it. I will post photos of this new issue.

I am also swapping a 95-97 gated shifter into my 91 when i fix this.

The one on the left is from my 100k spare trans which i broke. The one on Right is the bad part from my 270k car.

[Erich]

I have a modified arm now that is thinner and will fit on the stud and can allow me to put a nut back on it.

If anyone has this problem. I grabbed a couple extra stock brackets.

[VBdenny]

whoa. not sure what all the pictures were but the solution is simple. There is a wire broken in your trunk. I've fixed mine twice and can tell you that it is a pretty simple and very inexpensive fix. This is a very common problem on early LS models. send me a email or message and I'll see if I can dig up some pictures.

[Erich]

whoa. not sure what all the pictures were but the solution is simple. There is a wire broken in your trunk. I've fixed mine twice and can tell you that it is a pretty simple and very inexpensive fix. This is a very common problem on early LS models. send me a email or message and I'll see if I can dig up some pictures.

There is NO BROKEN WIRE, NO FRAYED WIRE. Read what i wrote.

This post is geared towards finding a broken wire that is not there. I tore my trunk all apart...stripped wires back to find NO BROKEN WIRES. I still need to clean all that mess up.

I put the photo's up to show someone what i had to do and what i went through.

Salt and water corroded the cracking part and the nut on the shifter. I sheared the nut off trying to swap the selector switch. I retrieved a used one from a SC400...that didn't shear off when i took it off.

I replaced it..still need to adjust it but the light went off.

What i would appreciate is someone pin pointing where the actual wires break. I do not believe the wires break randomly over a 3 feet of wire i checked in my trunk.

BTW, I am working on a multiport injection onto an olds 455 for a 67 cutlass 442 convert. I noticed the 66 in your sig.

[VBdenny]

I had a couple Buicks with 455cid's and that is one moving engine. Mine has a 250 with 3 on the tree. It mainly sits next to my truck in the garage, neither which get much use.

Okay so you checked the wires. The way the wires are tucked into the trunk hinge they are forced to bend repeatedly a certain way. When I first looked I didn't see the broken wire either because the insulation was not broken. If your wire isn't broken as you claim, you might find where the other end goes. I lived in Syracuse for many years and after 5 years in salt, a car is all done.

Roll down here to southeastern Virginia and pick one up. I see 90-94 for 3500-6000 around here.

[Erich]

I drove it 200 miles so far and the problem is gone. I need to adjust the switch on the lift it is slightly off. So the switch was bad.