mardyn

As I get ready to upgrade from my current Turbo 400 to a 700R4, I'm considering the cost factor.

I was expecting about $1500.00ish could easily get the job done at a competent transmission shop but the estimate is coming in higher than I expected.

Anybody have any recent experience in this arena?

Thanks for your thoughts.
mardyn

Rodnok1

Are you looking for used or rebuilt prices? Don't think I'd pay a trans shop to do it since it's a swap and nothing internal.
Labor probably run you 500 plus I bet.

mardyn

No, the transmission shop has the rebuilt 700R4 in stock, I was gonna drop off the car and let them handle the whole job... they told me last year probably about 1500.00ish out the door, now it's gone up another 500.00.

and it might be worth it... I'm sure I could do it myself, but someone who does it everyday would be much more proficient at it than I would...

mardyn

brick1234

Sending you a pm may be able to help both us out

doorgunner

Do a forum search...there are very good threads on this subject! Make sure the rebuilt transmission is 1989-newer....they are said to be better built.

mrvette

My '72 vert was a 4 speed car, and the first automatic I used was a 700 trick is, being shorter it still needed that 'shoe' that mounts to the cross support extending it out forward....and you need to shorten the drive shaft too.......

I went to a 200 4r trans because it's more suited to the install, sets on the cross support directly, and you don't need to shorten the drive shaft.... when I say more suited, the first gear is 3-1 ratio, second is 1.8 the rpm drop in driving across an intersection is just krazy, especially if you have a shift kit in it....I happen to like Trans Go.....

but in traffic, that rpm drop tends to bog the engine.....

but the 200 4r has a 2.56 first gear and the drop is not nearly as bad, much smoother operation, and still a TG shift kit of course.....

obviously you need hook up the lockup converter, but I have FI on my engine, so computer locks it.....you can just make the lock up in 4th only with a pressure switch in the valve body...but the shop should know how to do that.....

mardyn

I considered the 200 4R as well but with the 3.08;1 rear, I felt the 700R4 would be a better match for me.

Thanks for all the great info.

mardyn

Swift_C3

my trans swap was costly... started with a 200-4r, rebuilt it put it in the car and the pump failed immediately...being a novice, i'm positive it was my fault for not lining up something properly, went to a trans shop and $2,100 later got slightly upgraded 700R4, sure I could have installed it myself, but I was starting to get frustrated by the whole thing as I didn't have a garage to myself and was sharing it, therefore felt more rushed.

In the end, my first gear is super short as in from a stop sign to half way into the turn its shifting to 2nd...

mardyn

700R4 has a lot of reduction in 1st... I think it can be adjusted to stay in first longer but it may be a programming issue within the valve body governor circuits.

mardyn

mardyn

So, the process begins:

I dropped the car off at the transmission shop this afternoon for the 700R4 conversion.

Wish me (us) luck.

mardyn

cobrachuck

A couple grand for this swap is not a bad deal. It made my the car drive better & more pleasant to drive even with the stock L48.
I did my 700R4 myself for $1,500 it was work even with a lift.
Good luck.

7T1vette

Are they installing it, too? There are other expenses to get that unit fit into the car and running: shortening/balancing the driveshaft, T/V cable, transmission crossbrace and mount changes, dipstick changeout, exhaust work, etc.

If they just raised the price of the box $500, go to another shop. They are just gouging you because it's a Corvette.

mardyn

Complete install quoted at 2150.00 if they can make the existing cross member work. Includes all the necessary stuff to complete the conversion....

Transmission Shop owner recently completed a similar conversion on his own 1979 C3, so he's familiar with the process already.

I'm confident I could have done the job myself, but I would have wrestled with it for a month or more (even though I have a nice two post lift) and then would still have $1500 or more tied up.... "sometimes a man has got to know his limitations" and this job was one that I just did not want to tackle.

mardyn

TPI BOY

I had mine done 5 years ago, runs great no problems
cost me 1,500

mardyn

3 weeks and $2370.00 later... picked the car up today. More difficult installation than expected plus had to bend up some new exhaust pipes.

Car drove good on the way home, 70 mph is now 1850 rpms vs 2500 rpms before.

I'll report in later once I get a few more miles on it and have a better feel for the changes we made.

mardyn

mardyn

Quick update #3

I've driven the car a few more times since I got it back. The new transmission continues to work as planned as I try to get used to the changes.

First gear is slightly lower as expected and although I have not really romped on it yet, it feels pretty good.

I opted for a hydraulic lock up kit for the converter... it also seems to work as advertised and I can feel it almost like another shift.... it comes in a the top of 3rd gear just a bit before shifting into 4th or overdrive.

I'm not real happy with the TV cable bracket but it's buried beneath the air cleaner base and I can live with it for now until I can come up with something better.

Overall, I'm pretty happy with the whole thing so far... it took longer and cost about 10% more than initially estimated but I guess that's typical of most mods to these cars now days.

Thanks for following along.
mardyn

MSGT-R

I am embarking on this modification too.

I have already rebuilt a 1985 unit myself, purchased the overdrive shifter kit from Ecklers, the crossmember from Bowtie Overdrives, and I'm waiting for a call-back from Whatever it Takes for the pre-1984 tailshaft housing that is required to run a conventional rubber trans mount out-back. I already have a place to do any required driveshaft mods in my area. I have not purchased the TV cable bracket since I'm not yet sure what carb I'll be running, but that will come from Bowtie Overdrives as well.

I will take lots of pictures and do a write up of the installation when it all comes together.

In the meantime, thanks for your thread!

cv67

That cost if they are messing with the crossmember exh little stuff isnt too out of line if its done well. If you mess with the TV bracket make sure that cable doesnt change adjustment at all.

mardyn

OK, it's now been a few months, a few more miles and as promised, it's time for another update:

Today's date is 02/14/17

The car and transmission are still working OK, but really has seemed a bit lethargic since the conversion, particularly given the lower gear ratio in first.

After discovering that the head lights would no longer open last week, I finally took time to see what was going on under the hood. They had disconnected and plugged the vacuum source for the shift modulator (TH400), but in doing so, also disconnected the vacuum supply to the vac reservoir for the head light actuators. Quick fix on that problem by reattaching the supply hoses in the correct locations... not too big of a deal.

but, come to find out, the TV/throttle cable bracket they supplied (RE: bitch about TV cable bracket in previous post above)
has the incorrect geometry for the Throttle cable and only allows the about 60% opening on the carburetor....

It does run (pretty good) on the primary side with the secondary side just beginning to open.

My plan is to revise the bracket and relocate the throttle cable lower to correct the misalignment and geometry issues once I get back on it next week. It should make an noticeable improvement with 100% throttle range.

I was also able to sell my Turbo 400 to offset some of the cost of the conversion.

Lesson learned: There were so many red flags and bells and whistles going off telling me to go elsewhere, and I chose to ignore my gut feeling and use this shop anyway... big mistake on my part. They talked a good game and I got sucked in by the bull ****.

My continuing issue is now I don't trust what they said regarding the rebuild process on the R4. It seems to be working as expected for now, but who knows for how long?

I hope this thread will assist others in our community who are considering similar overdrive transmission 700R4, 4L60 or 200-4R style conversions for their own cars.

Cheers, mardyn