So I need a oil sending unit, went to autozone and they had 3 of them one of which was a duralast so I decided to go with that. they asked me what thread size, its either 1/8 thread, or its 1/4th thread... now I have no idea what it could be lol, and no way to tell without physically removing it since im usually busy all day I can not. does anyone know what it is?


Also the hose to that connects the Vacuum modulator on the tranny case has a nice size hole in it (the hose wraps around behind the EGR valve and to somewhere i dont know. Do i need to replace the entire modulator? its not the hose that really has a hole in it, its the fitting at the end of it that has the bolt in it.

Btw this is the 3 speed with Automatic Overdrive TH-125 (if i remember right)


Car information

1991 Lumina Euro 3.1 MFI Vin-T
TH-125 3 Speed automatic Overdrive transmission
No abs
Gauges not dummy lights, Same cluster as Z34 (not the ugly buick one)

Anyone have any input on this? i would gladly appreciate it.

BTW info for you 90 - 94 Lumina owners, Dont destroy your rear Deck cover, i did on mine and its $50 to get a used one with the pins :(

replace the vacuum line going to the modulator so your trans will shift properly. The th125c is a non-overdrive trans, but does have the lock up torque converter for better highway mileage. Get me the last 8-digits of your vin, and I can tell you which oil pressure switch your car requires.

the last 8 numblers/letters of my vin are "M9251748"

I want to replace that Vacuum line but i fail on where to find it. im just about to hit the junkyard and find one. i was going to do it before but eh with school and work you get busy ya know.

Thanks richtazz appreciate the help :D

i also heard something about that if your modulator goes bad or you get a hole in the hose that you can suck Tranny fluid into the engine or something like that? i dunno but just wondering.

According to the Parts guy at the Chevy Dealership here in hayward there is no such thing as a Vacuum modulator on a 3 speed transmission. he looked it up on the computer. 1991 Lumina Euro. he searched the Vin to make sure and there is no such thing... so im at a loss and i dont know what the rubber piece is. im attaching a few pictures so you guys might be able to tell what this part is...


http://img.photobucket.com/albums/v205/NK2186/Lumina%20Z34/09-24-05_1100.jpg
that is the rubber piece towards the left, you notice that the Transmission is on teh right its the silver part


http://img.photobucket.com/albums/v205/NK2186/Lumina%20Z34/09-24-05_1101.jpg

This one is another one a little closer, you can see at the bottom how its cracked, well if u move it a litltle its a big hole.


http://img.photobucket.com/albums/v205/NK2186/Lumina%20Z34/09-24-05_1102.jpg

this is the top part of the piece, its a hard plastic to a hard line going up past the EGR and behind the engine on teh passenger side... i dont know what to but i wish i did.


this is all on the right side of the engine bay. right under the Air box, and a little back and to the left.


Does anyone have an idea of what this is?


Also for the past 2 nights my car has died on me, i can be driving with no throttle input and the car just died. it does it randomly. and sometimes i get a RPM surge which you can feel. it does this when it wants to. but only when it's warm. The SES light is off, and has never come on. Im not driving my lumina untill i fix this problem. This way incase it is something bad i can fix it before the idiot light comes on saying that you need to pay $500 because you just broke something.

The other reason is the other night it almost got me killed, i was on one of those loops that gets you on the freeway from an overpass and she died going through one of those, there was a car about 100 feet behind me and i was hitting the brakes tryign to stop since i lost steering and i could barley turn almost went over the ditch and into the bottom gaurd rail, the car behind me didnt notice that my car stalled about came about 1 foot from my rear passenger side. scared the crap out of my passenger heh.

so yea if anyone knows why its doing that also i would love to hear some input. im thinking its a Vacuum problem, hence i want to get this problem i posted about fixed...

that isnt a hose, its a cable, it is the cable that controls your downshifts, its called a TV cable, of all things.

Thanks for letting me know i will look into getting a replacement asap. Thanks very much Jonn