82 Transmiision
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Joined: Nov 2011
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82 Transmiision
My friend has an 82 that he bought with the Injection Changed to Carb. He can't manually shift it, and thinks it may be due to the injection removed. Any thoughts on how to get it to shift manually?
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
Chances are that the vacuum modulator on the transmission is 'shot'. Not a big deal to fix: about $20 for a replacement modulator from car parts store; remove modulator with 1/2" box or open-end wrench. put pan under to catch small amount of trans fluid run-off; pull the modulator out and insert new one (put a wipe of trans oil on the new O-ring before inserting). Bolt retaining strip back in place, connect vacuum line to new modulator. Go have fun.
P.S. bad modulator will only allow trans to shift at high rpm shift points (4000 rpm or higher). You don't have to go WOT, just accelerate and keep it going until it shifts. If you finally get a 1 to 2 shift made, the modulator is your problem.
Note: The '82 C3 had the first year's production of 700R4 overdrive transmissions. It is a good unit; but there were some 'weak' areas in its design that were improved in the following 2-3 years. If you use the car 'normally', it will be fine. If you want to use it as a 'drag car', get the trans rebuilt with new guts. Otherwise, it will throw cr@ps and you will be replacing the whole transmission after it fails internally. The fact that it is still running now, demonstrates that it is robust for 'normal' use.
P.S. bad modulator will only allow trans to shift at high rpm shift points (4000 rpm or higher). You don't have to go WOT, just accelerate and keep it going until it shifts. If you finally get a 1 to 2 shift made, the modulator is your problem.
Note: The '82 C3 had the first year's production of 700R4 overdrive transmissions. It is a good unit; but there were some 'weak' areas in its design that were improved in the following 2-3 years. If you use the car 'normally', it will be fine. If you want to use it as a 'drag car', get the trans rebuilt with new guts. Otherwise, it will throw cr@ps and you will be replacing the whole transmission after it fails internally. The fact that it is still running now, demonstrates that it is robust for 'normal' use.
Last edited by 7T1vette; Aug 9, 2021 at 03:33 PM.
Melting Slicks
Joined: May 2021
Posts: 2,265
Likes: 1,310
From: Fleming Island, FL
The 82's 700R-4 doesn't have a modulator. Instead it uses a throttle cable. If this cable is disconnected the transmission won't shift properly and will burn up very quickly. It also a nonlinear movement and a different geometry on the throttle shaft as compared to other car's. Also the 82 doesn't have a manual 1st.
Last edited by Fly skids up!; Aug 9, 2021 at 04:05 PM.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
Oop! That's correct--700R4 has a throttle valve cable (T.V.) rather than a modulator. ('old' brain fade....)
It may have become disconnected at the carb linkage or internally. Again, you can test if that is the problem (or not) by getting the rpm's up high enough to shift. If it won't shift...even at high rpm's, you will need expert diagnosis at a trans repair shop. I would choose a good local shop over some national chain store.
It may have become disconnected at the carb linkage or internally. Again, you can test if that is the problem (or not) by getting the rpm's up high enough to shift. If it won't shift...even at high rpm's, you will need expert diagnosis at a trans repair shop. I would choose a good local shop over some national chain store.
Last edited by 7T1vette; Aug 10, 2021 at 07:55 AM.
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
The T.V. cable is a 700r4's lifeline...its "brain".......this MUST be properly set and if changed to carb...the correct bracket used to pull the cable......the wrong bracket will pull it incorrectly for a given throttle position.
Jebby
Jebby
Le Mans Master
Joined: May 2007
Posts: 5,019
Likes: 1,119
From: North tonawanda NY
^ and the transmission will burn up quickly in many cases if this cable is not adjusted right. being that he went from the throttlebody injection to carb he needs to have the correct brackets for the 700r4 or 2004r trans.
Burning Brakes
Joined: Feb 2020
Posts: 904
Likes: 569
From: Central NJ
he needs to have the correct brackets for the 700r4 or 2004r trans.
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