Auto Trans
Thread Starter
Intermediate
Joined: Sep 2003
Posts: 45
Likes: 0
From: Milano, Italy
Auto Trans
Hi everebody..
I just have my automatic transmission rebuilt.
After a few days of perfect working, right now it shifts to the overdrive too early.
Apart from this, the transmission is very smooth and the kick down works very well too.
Any suggestions?
Thanks and greetings from Milan, Italy
Pietro
I just have my automatic transmission rebuilt.
After a few days of perfect working, right now it shifts to the overdrive too early.
Apart from this, the transmission is very smooth and the kick down works very well too.
Any suggestions?
Thanks and greetings from Milan, Italy
Pietro
Thread Starter
Intermediate
Joined: Sep 2003
Posts: 45
Likes: 0
From: Milano, Italy
Hi. Thanks for your reply.
It used to shift at approx. 90 km/h, now it shifts at about 70 km/h and I have to push the gas a little bit more in order not to have the car running at low rpm..
Could it be the kick down cable?
Thanks
Pietro
It used to shift at approx. 90 km/h, now it shifts at about 70 km/h and I have to push the gas a little bit more in order not to have the car running at low rpm..
Could it be the kick down cable?
Thanks
Pietro
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
Originally Posted by CorvetteItaly
It used to shift at approx. 90 km/h, now it shifts at about 70 km/h and
I have to push the gas a little bit more in order not to have the car
running at low rpm..
Could it be the kick down cable?
I have to push the gas a little bit more in order not to have the car
running at low rpm..
Could it be the kick down cable?
occupied elsewhere, I will comment.
90 km/h = 56 mph
70 km/h = 43 mph
From transmissioncenter.net
"After the cable is adjusted the approximate shift points
should be 15 to 18, 25 to 30 and 40 to 50 MPH at very light
throttle depending on tire size and axle ratio."
should be 15 to 18, 25 to 30 and 40 to 50 MPH at very light
throttle depending on tire size and axle ratio."
"Sometimes on a newly rebuilt 700R4 or 200-4R transmission,
it may not make the 3-4 shift when first installed. A stuck
valve, trash in the fluid or an air pocket, usually causes this."
From TCI it may not make the 3-4 shift when first installed. A stuck
valve, trash in the fluid or an air pocket, usually causes this."
"c. Road test the vehicle. Under moderate acceleration your
shift points should be close to the following:
1-2…………………15-20 MPH
2-3…………………25-30 MPH
3-4…………………40-45 MPH
Other sites say much the same, a 3-4 shift normally occurs at 40-45 mphshift points should be close to the following:
1-2…………………15-20 MPH
2-3…………………25-30 MPH
3-4…………………40-45 MPH
(64-72 km/h). It wouldn't hurt to check a factory service manual for
Corvette to see whether there is any variation for Corvette. If not,
and if everything else about your car is stock (gear ratio, tire diameter
& ?) then the 3-4 shift seems to be normal as it is now.
The 'kick down cable' is better described as the Throttle Valve or
TV cable. It is important that this be adjusted properly or transmission
life will be greatly shortened. If you wanted to readjust the cable,
here is a thread with discussion and instructions: T.V. cable adjustment
Perhaps people with more to offer will also post replies?
.
Advanced
Joined: Feb 2005
Posts: 77
Likes: 0
From: N. Tonawanda NY
I had my 90 tranny rebuilt as a street/strip with other performance parts and when driving it normaly it shifts in to over drive @ 40/41 mph and when I stand on it I an't shure it just goes. Try adj the TV cable
Le Mans Master
Joined: Aug 2005
Posts: 5,002
Likes: 5
From: No Opti Here Tn
St. Jude Donor '06
You should ask the place that did the work to make the adjustment or you could just push down on the go pedal harder
I used to have an Alfa Spider
Wish I still had it
I used to have an Alfa Spider
Wish I still had it
Le Mans Master
Joined: Apr 2005
Posts: 8,077
Likes: 4
From: Scarborough ONTARIO
I have the same problem after pete k rebuilt mine, he installed sonnax 730 (sami as corvette governor), 3-4 was waaay to early like 35-38 mph so, after i bought this : http://cgi.ebay.com/ebaymotors/700-R...QQcmdZViewItem
this shifts so nice 3-4 takes place at 45-48 mph beautiful just beautiful and seller is nice to ship quick n it was easy install, dont have to take exhaust out, just needed loooong screw driver and u done with it. I highly recommend this seller. sami.
this shifts so nice 3-4 takes place at 45-48 mph beautiful just beautiful and seller is nice to ship quick n it was easy install, dont have to take exhaust out, just needed loooong screw driver and u done with it. I highly recommend this seller. sami.
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Race Director
Joined: Feb 2004
Posts: 12,517
Likes: 19
Sami's advise is correct. However, if the same governor that was in the trans(before the rebuild) is still there, shift quality should be the same as before the rebuild. Anytime shift timing or quality is changed suspect the tv system first. There is no kickdown cable on a 4l60/700r4. The cable that goes to the throttle body ic called the tv cable. It is critical that it is adjusted perfectly. If any doubt, put a guage on the trans to verify. Approx 60psi at idle and approx 160 ot wot is typical. Boost valves and pressure regulator spring upgrades will raise these figures.