gearbox problem. please help me if you can.

[zwrangler]

hey everybody,
I got a 93 z28 and i recently had to get a new gearbox since i fried my old one. Ever since i got the car back though it has never been 100% and has been just crap basically. My fuel mileage is shot to hell and the optispark is dying out causing serious hesitation in lower rpms. The throttle response is gone to hell too, before i used to barely put my foot on the accelerator and the car would be flying but now I have to really step on it to get it moving. Anyway, the main problem is since i got this gearbox the car doesn't have that powerful kick anymore when driving it, almost like its lost all its torque. What I mean is when i'm on the highway and just put my foot down all the way my car doesn't accelerate as fast as it used to and the rpms barely get over 4. Feels like my car has 200horses instead of the 290 or so it should have. Last night I barely kept up to a turbocharged corolla on the highway, so I've decided enough is enough and I am willing to save up every cent i earn to get back my old car performance. I've had this gearbox in for around 3 weeks now and I've had enough. This is the 3rd gearbox this guy put in my car and i don't think its gonna get any better than this, so I have given up on taking the car back to that idiot. I think the next option is to find a wrecked camaro and buy a gearbox and put it on.

So My questions are (1) if I find a wrecked camaro z28 auto between 1993-97, will their gearbox bolt on with no hassles or does it need to be from a 1993 camaro in specific? (2) Also, and more importantly will it perform like the old one did or will it still give me the ***** like this one does now. (3) do I need anything else besides the gearbox itself when i'm converting it from one car to another (such as rear gears or anything)? (4) Is it possible he put in a gearbox from a caprice or something, since i read all gm parts are compatible, and could this be the problem?? Sorry, I know these may seem like newbie questions but I really don't know much about the camaro gears and stuff not related to the engine. Thanks for all the help, your feedback is greatly appreciated.

[DJ Taso]

Bring it back where you had the work done and file a complaint. If they refuse to fix it call the B.B.B. and tell them about the situation. I don't think they would want a complaint on their company record.

[zwrangler]

I've already taken it back to the place 5 times and as i said, this is the 3rd gearbox he's put in. He really doesn't know what the hell he's doing even though he works on many luxury cars like bmw m series, newest audi's and even has a couple of porsches there now. Just goes to show, sometimes appearances can be deceiving.

I'll get a full refund as soon as i can find an alternative though and i'm thinking now of getting a gearbox out of another camaro like i said coz there really aren't many good gearbox places or mechanics in this country unless you're willing to be ripped off hardcore. I live in the emirates (middle east) by the way, so its not like theres any consumer board i can complain to here anyway alas, my original questions about converting from one car to another is my last option right now.

[tabahr]

Your post is a little confusing.

By saying "gearbox" we assume a manual transmission. Automatics are refered to similarly as a "slushbox"

Assuming you have a 6-speed stick, what is wrong with it? Does the clutch not feel right? Does the shifter pop out of its gears?

The ratios of the gears inside the transmission can effect the power curve to the rear wheels, but not the actual horsepower produced. In 1993 the cars got a T56 6-speed with lower ratios than in following years. The ratios were as follows:

1st 2nd 3rd 4th 5th 6th
1993 3.36 2.07 1.35 1.00 0.80 0.62 (std w 2.73:1 rear)
1993 2.97 2.07 1.43 1.00 0.80 0.62 (G92 w 3.23:1 rear)
1994- 1997 2.66 1.78 1.30 1.00 0.74 0.50 (3.42:1 rear)
** 1994 and newer cars got CAGS (1-4 skipshift)

If they replaced your transmission with one having higher ratios, your car will seem slower. I'm pretty sure this is probably what happenned. That is why you notice the RPMs are different than they used to be. You need to have the proper trans from a 93 installed in your car. I bet your transmission is a 1994+ model with a CAGS solonoid on it and it just isnt plugged into anything. If I were you, I'd get the 1993 T56 with a 3.36 first ratio. That would make a difference. It's probably what you had in the first place.

[zwrangler]

I'm sorry about the confusion. No, I have an automatic transmission. basically when i put the pedal to the floor from a stop, the car will launch like an absolute beast. BUt this is the only time it launches nicely. If I am going even as low as 20kms/hr and I floor it to the max the car builds up speed slowly and slugishly and usually the gears will shift at around 4000rpm which is just disgusting since the car has barely gotten to its potential rev range. Also, I really have to put my foot down on the gas now to get the car going. AS for highway driving, forget about it, the only way to get some decent response from my accelerator is if i manually shift the gears, but this wrecks the tranny anyway. Also, when i'm cruising at a normal speed, like say 80kms/hr the revs don't really go up at all unless i really really put my foot down. I can hear the engine getting louder but the revs stay the same unless i floor it. SO basically, the mechanic put in a **** weak transmission. I'm seriously so frustrated coz my car is performing like a 3 legged dog at a race track

Like I said, at this point I'm saving every penny I make at my side job at university (I'm a uni student) which isn't much, but i'm willing to save up and spen whatever i have to to get it back to being my beast. Thanks for replying, helps to nkow someone out there is actually trying to help with my problem.

[tabahr]

OK... someone back me up on this....

My theory.....The trans is shifted electronically by the PCM based on vehicle speed and throttle position... right? ...or.. did that begin in 1994?

All 4L60 automatic transmissions have the same ratios... right?

the ratios in the 4L60 transmission are:
1st 2nd 3rd 4th
3.06 1.62 1.00 0.70

How could his trans be shifting at the wrong time if it is the PCM calling the shots? Did the 93's have a TV cable? Could his be that badly out of adjustment if they did have one?

Could someone that is wiser than me in this area answer these questions?

Here is a link to a performance 4L60E:
GM Performance Parts (GMPP)
http://www.sallee-chevrolet.com/Chev...ions/4L60.html

[Rob B (shoebox)]

TV cable. Get it adjusted.

[tabahr]

Originally posted by Rob B (shoebox)
TV cable. Get it adjusted.

I kinda thought so. Thanks Rob. I hope that helps him.

[Rob B (shoebox)]

Originally posted by tabahr
I kinda thought so. Thanks Rob. I hope that helps him.

This question was posted on another board and I had the same response you did. Then discovered here that it was an auto. Sorry zwrangler, I was a little irritated because of the research and thought to find you an answer and it did not even apply (same as tabahr did). I'm over it now, though.

Sounds like the TV cable.

[zwrangler]

thanx for all the help guys. OKay, i'll take it to a mechanic this weekend and ask him if it is the tv cable. If it is then it shouldn't be too hard or costly to fix right? anyway, thanks for all the help.

On a side note, I don't know if it makes a difference but with this new auto gearbox I can now manually shift it into 1st gear which was not possible with the stock gearbox. Thats why i thought maybe it was the transmission he put in and not anything else that was wrong. Again, thanx for all the help.

[tabahr]

Originally posted by zwrangler
thanx for all the help guys. OKay, i'll take it to a mechanic this weekend and ask him if it is the tv cable. If it is then it shouldn't be too hard or costly to fix right? anyway, thanks for all the help.

On a side note, I don't know if it makes a difference but with this new auto gearbox I can now manually shift it into 1st gear which was not possible with the stock gearbox. Thats why i thought maybe it was the transmission he put in and not anything else that was wrong. Again, thanx for all the help.

The ability to manualy shit to first is a function of the shifter inside the car, not the transmission. Many cars were unable to shift to first because of noise regulations. There is a tab that can be cut out of the shifter to allow full functionality. The guy that did the installation must have done this I am speculating.

You do not have a "1" on your gear selector, do you?

It just goes PRNDD2 right? And you are saying now it goes to 1 even though it isnt labeled for it, and it didnt previousely?

[zwrangler]

It just goes PRNDD2 right? And you are saying now it goes to 1 even though it isnt labeled for it, and it didnt previousely?

yup, thats exactly what i'm saying. I can now manually shift it by pulling the shifter and it kinda clicks and viola I'm running 1st gear.

Also, I got a reply on another forum where i posted this question and someone suggested that it may be a problem with my sparkplugs and wires which is giving me such bad rpms and hesitation. A mechanic told me my plugs need changing but nothing really urgent, but i'm changing them this weekend anyway. DO you think this may have anything to do with it rather than the tranny being the problem?

Sorry, but one last question, I'm fairly familiar on the LT1 but never heard of a part called the TV cable on the LT1 so what is it exactly?? Thanx for all the help and patience.

[tabahr]

The TV cable goes from the accelerator linkage on the throttle body to the transmission. It provides the transmission with input as to throttle position. I believe it regulates the pressure in the transmission to control when it shifts and how hard, as well as when it kicks down into passing gear.

This really sounds like the problem you are having.

Rob has a diagram showing it...
http://shbox.com/1/tv_cable.jpg

[zwrangler]

yeah, now that yuo explained what the tv cable is I know exactly what you're talking about. ANd guess what, yes the tranny guy was fiddling aruond with it and pulling and tightening when I got the car back. i distinctly remember him pulling it coz he did that in front of me. I hope this is the problem. Thanks man, you and everyone else have been a great help.

[Detroit_Bird]

I think I have an explaination as to why you can shift into 1st now- when I last changed my A4, I misadjusted the shifter linkage. That meant that when the console read "2" it was actually in 1st, D was actually 2nd, and OD was actually 3rd. I still don't know how, but the thing would still go into Park when selected. Anyhow, this may explain why you can suddenly select 1st and/or why you may be in 3rd gear on the highway(hence your car acts different at higher speed)

Also- let me know if you want the ability to properly select 1st gear- it's a simple free mod that requires about 10 min to do.