This is a continuation of another post of mine:
https://www.corvetteforums.com/m_56225/tm.htm

The mechanic told me that both the overdrive unit and the manual transmission have problems and that I'm looking at either a rebuild or a replacement. I also found some other interesting things out about my '85 but that is for another post.

I have yet to be informed of what the actual problems were with the overdrive and manual transmission, but they're working up a few quotes for me. I wanted to outline my options here and see if anyone has any experience with this situation and could possibly help me to make a decision.
1. I can do a rebuild on the existing transmission. Not sure what the cost would be, perhaps someone could help me with a ceiling price for choosing another option?
2.They may be able to pull a 4+3 out of a 1988 with about 30k on it. It hasn't been rebuilt, so it is the original for that car.
3. They suggested a Keisler PerfectFit 5 speed which they say they've used as a direct replacement many times with good results. I'm reluctant to spend a lot of money on a brand new transmmission, but I want to do the right thing for the car. I looked online and saw three models, TKO-500 (.68 Overdrive) TKO-600 (.64 Overdrive) and TKO-600 (.82 Overdrive) The last two have different overdrive ratios but are the same model. I'm not really sure what ratio is right for me because I don't know what the numbers mean, but I would like more speed/power getting to 60mph than after.

Any comments or suggestions I would really appreciate!

Thanks!!

 

The 4+3 installed in the '84 to '85 had a flaw that burned out most of the overdrive units. :Check out this website CorvetteActionCenter : Technical Article Rebuilding the Doug Nash 4+3 .This will explain the defect and repair option. A 4+3 out of a '88 at the right price most likely be cheaper. The 5 speed or 6 speed upgrade will most likely cost be $3000+. Unless the T10 is grinding dust I would check out how bad the repair is unless the trans and overdrive from the '88 is sold as a whole Good luck.

 

Wow I got the estimate today and found out some more information. The 4+3 in the '88 is solid, and they want $2000 for it. Thanks YankeeCorvette, good to know that the '88 doesn't have that flaw... A rebuild would cost me $1275 more so that's out of the question. The master and slave clutch cylinders are both leaking so they quoted those and they've priced a new clutch. The EGR is also bad, (I was getting a Check Engine Light occassionally) and a right rear wheel bearing is VERY loose. For all of that, labor, and tax I'm looking at just over $4500. Seems high to me, but I don't think I have any other options that make sense. I'm thinking of calling the guy in the morning and telling him to do it. Going with the 5 speed replacement would be about $2500 more so I'm not going to be able to afford that... I can't afford this, but it's the cheapest option that I can think of right now without compromising. If they get the go ahead tomorrow I can have it back in a week. Can anyone tell me if this sounds good or if it's overpriced?
Much appreciated!

 

When my '86 burned out its overdrive it was due to lack of maintenance of the last owner. Three years ago it cost $1200 w/ a clutch and small parts thrown in. So the price is relative to the times. Doesthe '88 4+3 includes the transmission?or is it just the overdrive unit?Make sure you get it in writting what you are doping out the cash for. Get all old parts back w/ no B.S. about the old case. The core, if not smashed, is worth something as a whole on Ebay. You can chuck the parts yourself if you please, but rebuildables always have some value i.e. transmissions and overdrive boxes. Good Luck.

 

Ok I've had my baby back for almost two weeks now. At first I was very happy. I put in the 1988 4+3 transmission and overdrive unit. (both of mine were shot) it only had 30K original miles on it. I had a new clutch, slave and master cylinder, EGR valve, and they cut the flywheel? (not sure what that's about) They also found that the u-joints were really bad and needed to be replaced and the coolant system for trans needed a full flushing as it was black.
When I first got the car back the clutch was nice and tight, now it's seems to have almost a couple inches of "loose" space on the pedal. I did however notice almost right away that if I'm sitting at a light and go to take off slowly, if I ease off the clutch it starts to shake the car... pretty bad actually... Normal operation is ok, but if I slowly let off the clutch and give it gas there is a point at which the car voilently shakes. I usually try to move past that point quickly, or just avoid taking off slowly. Sometimes in traffic that's hard to do...
Even worse, for the last couple of days when I leave the house in the morning the clutch will go to the floor with no resistance! This morning I started the car in the garage and pumped the clutch several times to be sure that it seemed like it was working. After I back out of the driveway and started down the road, I went to shift into second and the clutch went all the way to the floor! I pumped it a couple of times to get it so that I could shift, but this happened for the first several minutes of driving.
What is going on!! Everything is new and this shouldn't be happening, I'm definately calling the garage today because they need to make this right. I'm just hoping that someone can tell me what could be causing these two issues so that I can compare it to what the garage tells me. After spending all the money I did to get this work done I'm not going to be happy if they charge more to make it right.

Thanks!

 

Two things very common to your problem. The slave cylinder is leaking or the slave master is leaking. Two, most likely,the hydrualic circuit which includes the both components metioned is full of air. The guy who did the work most likely needs to bleedthem out more. It is common to get air trapped in the system and get it stuck in the upper part of system. Don't stroke out these things happen and because one guy did all the work he is obligated to make the adjustments. The clutch chatter is one of the symtoms of what happenedwhen air is in the system. The flywheel was ground to make the clutch disc seat better and is always done when the job is done right. Although (if )the flywheel was over ground leaving too much runout the clutch will also chatter. Bring it back and everything will be OK.

 

i recently purchased a 84 vette with this 4+3 transmission.... it worked for a while then it wouldn't go into gear unless the car was in motion.... now it will not go into gear at all! i have been told that it could just be replaced with a T5... As i am the black sheep of the family we have plenty of T5's sitting around out of the many fox bodies my brothers have... Is this T5 swap gonna work?... and if not any ideas whats wrong with my trans?