Help with 700R4 transmission problem please
Thread Starter
6th Gear
Joined: Feb 2005
Posts: 6
Likes: 0
Help with 700R4 transmission problem please
I have a 1990 with automatic trans (700R4). Everything is close to stock and the car has 115K miles on the odometer. Here's the problem: After setting for the weekend, I drove it. It shifted normally first and second, but it goes into what seem like neutral after 2nd, and never gets to 4th gear. If I give it alot of gas/rpms it goes back to 2nd.
Up until now the trans has had no problems. The fluid and filter has been changed regularly.
Here's what I've done so far:
- inspected and adjusted the TV cable (seems fine)
- pulled the pan (oil and filter looks normal, no burnt smell)
Questions:
- Have I overlooked something simple?
- Is the transmission toast? (need to be removed and repaired or replaced?)
- If the transmission has to be replaced, what are my options for remanufactured units? I think the Corvette version of the 700R4 is different (shorter tail housing, among other things) so options might be limited.
- For those in Florida, are there any especially good transmission repair places in central Florida.
Thanks in advance.
Up until now the trans has had no problems. The fluid and filter has been changed regularly.
Here's what I've done so far:
- inspected and adjusted the TV cable (seems fine)
- pulled the pan (oil and filter looks normal, no burnt smell)
Questions:
- Have I overlooked something simple?
- Is the transmission toast? (need to be removed and repaired or replaced?)
- If the transmission has to be replaced, what are my options for remanufactured units? I think the Corvette version of the 700R4 is different (shorter tail housing, among other things) so options might be limited.
- For those in Florida, are there any especially good transmission repair places in central Florida.
Thanks in advance.
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
It's toast. The tail housing has the mount for the "C" beam. There are other "Corvette" features you want to retain, like the ability to stay in 4th gear and at WOT, larger servos, etc. It may be best to have your trans done by a knowledgeable local. If you opt to exchange your trans, you will want to insure the replacement has all the features you need. Swapping the tail housing is something anybody can do. If that is done, just make sure it is onto an otherwise, desirable trans.
RACE ON!!!
RACE ON!!!
Melting Slicks
Joined: Dec 2000
Posts: 2,719
Likes: 60
From: Fremont Oh
c4a1990,
It sounds like you may have a problem in the valve body... a coomon problem with that many miles , I would just have it rebuilt.
Actually my trans is in the shop as we speak I took out second on a high speed pass...
I had a similar issue with mine at about 92,000 and had to have it rebuilt. mine would skip 2nd and shift 1 -3,4 and slip a bit in 4th.
I hate to be a bearer of bad news but that is what it sounds like to me.
Mine cost about 3000 the first time, but they charged me lik 1000 for remove and replace. This time I did it myself. Perhaps someone can chime in about a great transmission place in your area. I have seen some rebuilt "Raptor" 700 R 4's for about 1900 dollars then you would have a few hundred in shipping...
Hope this helps ,
Mo
It sounds like you may have a problem in the valve body... a coomon problem with that many miles , I would just have it rebuilt.
Actually my trans is in the shop as we speak I took out second on a high speed pass...
I had a similar issue with mine at about 92,000 and had to have it rebuilt. mine would skip 2nd and shift 1 -3,4 and slip a bit in 4th.
I hate to be a bearer of bad news but that is what it sounds like to me.
Mine cost about 3000 the first time, but they charged me lik 1000 for remove and replace. This time I did it myself. Perhaps someone can chime in about a great transmission place in your area. I have seen some rebuilt "Raptor" 700 R 4's for about 1900 dollars then you would have a few hundred in shipping...
Hope this helps ,
Mo
Team Owner
Joined: Aug 2000
Posts: 24,125
Likes: 3
St. Jude Donor '14
several things can cause your problem. Could be a stuck valve in the valve body, or the servo not applying the pressure to the band. In either case, that's not good. It doesn't take much to burn the band which is necessary to go from 1st to second. The band is applied in 2nd and then again in fourth. With as many miles as you have on the tranny, an overhaul is probably right around the corner.
Melting Slicks
Joined: Feb 2005
Posts: 2,135
Likes: 0
From: Sebastian Florida
St. Jude Donor '06
Don't know where you are in CF, but I took my 300ZX to Remanufactured transmissions in O-town, they did a great job. I drove the car another 8k miles with no problems till a women pulled out in front of me an ended the Z's career.
They have shops all over Orlando, I took mine to the one downtown. They are a little slow, but they do a great job.
They have shops all over Orlando, I took mine to the one downtown. They are a little slow, but they do a great job.
Thread Starter
6th Gear
Joined: Feb 2005
Posts: 6
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It's hard to believe that It went from running fine to no 3rd and 4th gear in an instant w/o any warning! Luck I was a quarter mile from home rather than 1000 miles away.
I have a number (24212088) for an AC Delco Remanufactured unit and another number (8673955) for a GM remanufactured unit - both available from GM with a 3 year (50K mile) warrenty. Prices differ wildly from dealer to dealer, but are between $1000 and $1700. Any Preference? There is also a very nice GM high performance version (8686961) used on the 93 camaro Z28s - reasonably priced, no core charge. See:
http://www.sallee-chevrolet.com/Chev...ions/4l60.html
But, I think, this would require a tail shaft/housing changeout. How hard of a job would this be? Is it something I could do?
Also, regardless of what I do with the transmission, should I use the original torque converter? Is is difficult to seperate from the trans?
Thanks again.
I have a number (24212088) for an AC Delco Remanufactured unit and another number (8673955) for a GM remanufactured unit - both available from GM with a 3 year (50K mile) warrenty. Prices differ wildly from dealer to dealer, but are between $1000 and $1700. Any Preference? There is also a very nice GM high performance version (8686961) used on the 93 camaro Z28s - reasonably priced, no core charge. See:
http://www.sallee-chevrolet.com/Chev...ions/4l60.html
But, I think, this would require a tail shaft/housing changeout. How hard of a job would this be? Is it something I could do?
Also, regardless of what I do with the transmission, should I use the original torque converter? Is is difficult to seperate from the trans?
Thanks again.
Burning Brakes
Joined: Nov 2002
Posts: 807
Likes: 21
From: Los Altos CA
I had exactly the same symptoms but it happened while I was driving - accelerating. It happened twice about 3 years apart. In both cases it was broken internal parts. Was yours just parked between correct functioning and the problem? By the way, I am not hard on the transmission and my '90 is stock.
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Race Director
Joined: Sep 2000
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From: The Top of Utah
Originally Posted by c4a1990
But, I think, this would require a tail shaft/housing changeout. How hard of a job would this be? Is it something I could do?.
Originally Posted by c4a1990
Also, regardless of what I do with the transmission, should I use the original torque converter? Is is difficult to seperate from the trans?
Thanks again.
Thanks again.
To remove, pull off of the front shaft. No effort required. To install, push on while spinning. Listen for 2 clicks to make sure it has engaged each set of splines at the input. Your Helms will probably give you a dimension to check against to be sure it's all the way on.
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Thread Starter
6th Gear
Joined: Feb 2005
Posts: 6
Likes: 0
Thanks for the help guys
white90conv: Car is a daily driver (work), but was parked for the weekend. Changed a thermostat during the weekend, moved it in and out of the garage only. Friday it worked, monday it didn't. I'm, also, not particularly hard on the trans.
Carl Johansson: Are you anywhere near Florida. I'm leaning toward a remanufactured with a good warrenty.
CFI-EFI: Four bolts to remove the tail housing - does the output shaft come with it? Then could I use that GM high-performance 4L60 trans that I referenced and just swap out my existing tail shaft/housing? Then it would be a drop in.
I pulled the pan after this happened and there was nothing in the oil or filter, but good point about flushing the converter. Any recommendations on a converter upgrade?
Jake: After it happened I checked the trans fluid (it was a little high). I then pulled the pan and replaced the fluid (correct level) - still no 3rd and 4th.
Thanks again
white90conv: Car is a daily driver (work), but was parked for the weekend. Changed a thermostat during the weekend, moved it in and out of the garage only. Friday it worked, monday it didn't. I'm, also, not particularly hard on the trans.
Carl Johansson: Are you anywhere near Florida. I'm leaning toward a remanufactured with a good warrenty.
CFI-EFI: Four bolts to remove the tail housing - does the output shaft come with it? Then could I use that GM high-performance 4L60 trans that I referenced and just swap out my existing tail shaft/housing? Then it would be a drop in.
I pulled the pan after this happened and there was nothing in the oil or filter, but good point about flushing the converter. Any recommendations on a converter upgrade?
Jake: After it happened I checked the trans fluid (it was a little high). I then pulled the pan and replaced the fluid (correct level) - still no 3rd and 4th.
Thanks again
Drifting
Joined: Sep 2004
Posts: 1,638
Likes: 3
Originally Posted by c4a1990
Carl Johansson: Are you anywhere near Florida. I'm leaning toward a remanufactured with a good warrenty.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by c4a1990
CFI-EFI: Four bolts to remove the tail housing - does the output shaft come with it? Then could I use that GM high-performance 4L60 trans that I referenced and just swap out my existing tail shaft/housing? Then it would be a drop in.
I pulled the pan after this happened and there was nothing in the oil or filter, but good point about flushing the converter. Any recommendations on a converter upgrade?
I pulled the pan after this happened and there was nothing in the oil or filter, but good point about flushing the converter. Any recommendations on a converter upgrade?
Whether you saw it or not, there is debris all through your transmission, including the converter, cooler, and cooler lines. It is a normal consequence of transmission wear. No transmission warranty would be honored by anyone, if the converter and cooler circuit weren't at least flushed.
*I* am partial to my 2600 rpm stall, Vigilanti converter. I wish it were a 2800 or 3000, but I love it.
RACE ON!!!
Thread Starter
6th Gear
Joined: Feb 2005
Posts: 6
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CFI-EFI,
I appreciate you patience, but I still don't understand - maybe I'm just thick. If I change the tail shaft housing (easy to do) the transmission will mount to the support member like it did before. But, if I don't change the output shaft, wount the output shaft stick out too far and not attach to drive shaft without shorting it or the driveshaft? It was my understanding that the non-Corvette 700R4/4L60's are longer (besides the tail shaft housings being different).
I understand about the flushing, I will do it for sure.
I sure would like to use that GM Z28 transmission if I could make it fit without too much trouble - it seems to have all the right parts, is very reasonably priced, and even comes with a tc.
I think I'm going to go with a GM remanufactured trans, mostly because of the warrenty, but there's three different one to choose from.
Jim H
I appreciate you patience, but I still don't understand - maybe I'm just thick. If I change the tail shaft housing (easy to do) the transmission will mount to the support member like it did before. But, if I don't change the output shaft, wount the output shaft stick out too far and not attach to drive shaft without shorting it or the driveshaft? It was my understanding that the non-Corvette 700R4/4L60's are longer (besides the tail shaft housings being different).
I understand about the flushing, I will do it for sure.
I sure would like to use that GM Z28 transmission if I could make it fit without too much trouble - it seems to have all the right parts, is very reasonably priced, and even comes with a tc.
I think I'm going to go with a GM remanufactured trans, mostly because of the warrenty, but there's three different one to choose from.
Jim H
Last edited by c4a1990; Feb 17, 2005 at 02:11 PM. Reason: Add comment
Race Director
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The output shaft will need to be changed. This involves total dissassembly of the trans to get to the snap ring just in front of the lo-roller clutch. Some guys shorten the output shaft of a non vette trans by 1/2 inch. This amount makes it the same length as the vette. If you choose to shorten the output shaft, you must first measure the splines to determine if it is the long splined shaft or short splined shaft. Short will not work. Long will. The speedo gear also needs to be moved to the next hole for proper gear mesh.
Race Director
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I did not read every word of this thread. If I am repeating anything already said, forgive me. Keep in mind there are other things different in a non-vette trans. You cannot hold foot on floor and shift into overdrive. A valve can be purchased to correct that. Retail is between 50-80 bucks. The vette uses a different servo with more surface area resulting in a firmer solid shift. The vette uses a unique governer so that it shifts at approx 5k. Camaros may use same. I am not sure. A servo and governer for a vette runs about 80-100 bucks all said and done. I recommend keeping and fixing your trans if possible. You will be happier in the long run. 
Race Director
Joined: Sep 2000
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From: The Top of Utah
Originally Posted by Pete K
I did not read every word of this thread. If I am repeating anything already said, forgive me. Keep in mind there are other things different in a non-vette trans. You cannot hold foot on floor and shift into overdrive. A valve can be purchased to correct that. Retail is between 50-80 bucks. The vette uses a different servo with more surface area resulting in a firmer solid shift. The vette uses a unique governer so that it shifts at approx 5k. Camaros may use same. I am not sure. A servo and governer for a vette runs about 80-100 bucks all said and done. I recommend keeping and fixing your trans if possible. You will be happier in the long run.
I thought some transmissions had a minor shaft length difference, but wasn't aware that a shaft change or modification was necessary. I have been led to believe that the housing swap was sufficient. Of course if there is a "long shaft trans" like in the TH350 and TH400, the shaft would definitely have to be changed. I was going by what *I* had assumed to be reliable sources. I have not done this myself. I apologize if I have misled anyone.
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Race Director
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I never did check (with the yoke) to see if that extra 1/2 inch was interfering with the driveline. It may be fine to leave the extra 1/2 on. I will check this a little more closely on the next trans. For safety's sake, I just cut it off. I will figure this out `1 way or another as I am about to convert a van trans into a vette trans using the previously mentioned pieces (gov,servo,etc). I may make a tech tip out of it so it is there for everyone to see. I am certain about the speedo gear(drive) needing to be moved to the next hole though. If he does swap in the camaro trans I hope he will sell me the vette core. 
Advanced
Joined: Jul 2004
Posts: 64
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From: laguna niguel california
My 90 A4 did the same thing. I was just driving one day and the car suddenly had no 3rd or 4th gear. I ended up taking it to Chev. and they had to rebuild the transmission. Supposely the clutches for these gears were burned out.
BTW where in Cal. are you. Maybe I could come buy and help you with this.
BTW where in Cal. are you. Maybe I could come buy and help you with this.
Race Director
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From: The Top of Utah
Originally Posted by Pete K
I am certain about the speedo gear(drive) needing to be moved to the next hole though.
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