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c6 trans problem
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Matt Edwards
• Concord, CA, USA
• Registered on 5/18/2003
• 3 posts
Posted:5/18/2003 18:12
I recently purchased a 78 bronco for 500 as a restoratio project, i'm nearing completion only have two problems remaining and hoping someone can help. And thank anyone and everyone in advance for any information.

Problem One: My trany does not seem to shift into 3rd gear, not sure if it's not reving high enough or if there is a problem somewhere. I can't find any info in chilton or haynes about the transmission being operated off a vac, i'm quite new to all this what are other options than vac. Another thing i noticed is while shifting, from left to right it's Park, Reverse, Neutral, Drive, 2, 1 on my shift indicator, not sure if it's the wrong indicator, or what but while actually shifting i only go through park, revers, neutral, drive then one more, be it 2 or 1. so i only have 5 rather than 6 selections. Any ideas or remedies?

Problem Two: I had a horrible vibration while driving, by slowly replacing parts the speed where vibration occurs has increased. Thus far i have replaced Power steering pump and gear, though didn't think was related, i had no pump and gear was in horrible shape. More directly related i replaced my sway bar bushings and end links, tie rod, and drag link. Only thing i can think of left to replace or my Ball joints and possible wheel bearings. Running 35' tires which possibly has thrown a weight, but... if it were out of balance tires, would the vibration start slow then act up, currently the vibration comes out of nowhere and on deceleration, particularly without braking.

Once again many thanks to any help to get me playin in the mud sooner, these are my last two problems. OH yeah, and if anyone has any advice info on exhaust headers (whatever you call those things), and intake manifold so i can upgrade to a 4brl carb, and how big of a carb should i go for a 400cid.
edited 5/18/2003 18:12
Jason Rich  Club Owner
• Big Stone Gap, VA, USA
• Registered on 4/4/2002
• 30 posts
2 ATVs
1 Motorcycle
4 Vehicles
Posted:5/18/2003 19:33
Quote:
I recently purchased a 78 bronco for 500 as a restoratio project, i'm nearing completion only have two problems remaining and hoping someone can help. And thank anyone and everyone in advance for any information.

Problem One: My trany does not seem to shift into 3rd gear, not sure if it's not reving high enough or if there is a problem somewhere. I can't find any info in chilton or haynes about the transmission being operated off a vac, i'm quite new to all this what are other options than vac. Another thing i noticed is while shifting, from left to right it's Park, Reverse, Neutral, Drive, 2, 1 on my shift indicator, not sure if it's the wrong indicator, or what but while actually shifting i only go through park, revers, neutral, drive then one more, be it 2 or 1. so i only have 5 rather than 6 selections. Any ideas or remedies?

Problem Two: I had a horrible vibration while driving, by slowly replacing parts the speed where vibration occurs has increased. Thus far i have replaced Power steering pump and gear, though didn't think was related, i had no pump and gear was in horrible shape. More directly related i replaced my sway bar bushings and end links, tie rod, and drag link. Only thing i can think of left to replace or my Ball joints and possible wheel bearings. Running 35' tires which possibly has thrown a weight, but... if it were out of balance tires, would the vibration start slow then act up, currently the vibration comes out of nowhere and on deceleration, particularly without braking.

Once again many thanks to any help to get me playin in the mud sooner, these are my last two problems. OH yeah, and if anyone has any advice info on exhaust headers (whatever you call those things), and intake manifold so i can upgrade to a 4brl carb, and how big of a carb should i go for a 400cid.


First off the selector on your steering column is correct, second your linkage may be off causeing the the shifter to be wrong, as for as it running off a vacuum there maybe some internal ones but there is no lines on the tranny to hook up and also the third gear may just be gone because I lost the same gear in mine before I had it rebuilt.------ As for the steering my problem was caused by the front track bar bushings. It is the one that runs from your shock mount to the axle, these bushings get bad and all h*ll will break loose. If you replace these use polyeurthane bushings and the rubber ones wear out way to fast.

Also i have a c-6 out of a 78 bronco that was recently rebuilt for sale. Less than 2500 miles on it. not to mention the Dana 44 front end and a np203 transfer case, email me if interested at mudpig77@hotmail.com
Matt Edwards
• Concord, CA, USA
• Registered on 5/18/2003
• 3 posts
Posted:5/19/2003 00:23
The C-bushings? ordered two pair off of rockauto but didn't put on because only one got sent to me. will test that as soon as i get the other set. thankyou.
Robert Williams
• Baltimore, MD, USA
• Registered on 5/17/2003
• 9 posts
2 Vehicles
Posted:5/26/2003 08:58
If a C-6 is a C-6, then it dose have a vacume module. My '75 to '78 LTD was shifting poorly until I took her into a transmission shop. They replaced the vacum module and the plastic grommet on the shift linkage for a cost of $75. She has been a perfect lady ever since.
John Barrett
• West Palm Beach, FL, USA
• Registered on 1/31/2003
• 106 posts
1 Vehicle
Posted:6/10/2003 21:19
Quote:
I recently purchased a 78 bronco for 500 as a restoratio project, i'm nearing completion only have two problems remaining and hoping someone can help. And thank anyone and everyone in advance for any information.

Problem One: My trany does not seem to shift into 3rd gear, not sure if it's not reving high enough or if there is a problem somewhere. I can't find any info in chilton or haynes about the transmission being operated off a vac, i'm quite new to all this what are other options than vac. Another thing i noticed is while shifting, from left to right it's Park, Reverse, Neutral, Drive, 2, 1 on my shift indicator, not sure if it's the wrong indicator, or what but while actually shifting i only go through park, revers, neutral, drive then one more, be it 2 or 1. so i only have 5 rather than 6 selections. Any ideas or remedies?

Problem Two: I had a horrible vibration while driving, by slowly replacing parts the speed where vibration occurs has increased. Thus far i have replaced Power steering pump and gear, though didn't think was related, i had no pump and gear was in horrible shape. More directly related i replaced my sway bar bushings and end links, tie rod, and drag link. Only thing i can think of left to replace or my Ball joints and possible wheel bearings. Running 35' tires which possibly has thrown a weight, but... if it were out of balance tires, would the vibration start slow then act up, currently the vibration comes out of nowhere and on deceleration, particularly without braking.

Once again many thanks to any help to get me playin in the mud sooner, these are my last two problems. OH yeah, and if anyone has any advice info on exhaust headers (whatever you call those things), and intake manifold so i can upgrade to a 4brl carb, and how big of a carb should i go for a 400cid.


1. Yes there is a vacuum modulator that needs to be hooked up on the C6 tran's, secondly you must follow the directions in a chiltons manual and set the shifting indicator properly.

2. Can be out of balance tire or tires, Check and make sure your wheel bearing nuts are snug - maybe loose, make sure you got cater pins to stop them nuts from backing out too (not a good feeling to see your tire pass you up on a interstate hwy.)

Forums > SuperMotors Community Discussion > Engine and Drivetrain
c6 trans problem
Thread Statistics:     Users to Post: 4   |   Total Posts: 5   |   Total Views: 1374
You must be logged in to post in or subscribe to this thread.Pages: 1

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