should I just do it?
Thread Starter
Instructor
Joined: Apr 2003
Posts: 153
Likes: 0
From: San Antonio TX
should I just do it?
I have a 75 L-48 coupe - some of you know the story; the car was basically delivered undriveable. I've had the TH400 transmission rebuilt, and can't get the friggin' thing to quit leaking from the front seal - already replaced the front seal myself, and it still leaks very severely.
Long-term, I would really like to install a 5-spd manual in it - I love the stick. However, I had planned on just getting the car driveable asap - it's not just a toy, it's transportation for me! I'm getting really sick of messing with the TH400, to be honest, and am (of course) wondering if now is the best time to make the switch.
Question #1 - any other diagnoses? Front seal replaced, yet still leaking approx .3qt/min from the front seal...
Question #2 - What is the single hardest part of a 5-spd conversion? I have basic mechanical skills, and plenty of more skilled help.
Question #3 - How cheap could I do it? I would also consider a 6-spd from a Z-28/Formula if it is compatible - those are obviously readily available.
Obviously, any recommendations as to potential 5-spd (6-spd) kits would be most appreciated.
For those who have been such a big help before, thanks again!
Ben :banghead:
Long-term, I would really like to install a 5-spd manual in it - I love the stick. However, I had planned on just getting the car driveable asap - it's not just a toy, it's transportation for me! I'm getting really sick of messing with the TH400, to be honest, and am (of course) wondering if now is the best time to make the switch.
Question #1 - any other diagnoses? Front seal replaced, yet still leaking approx .3qt/min from the front seal...
Question #2 - What is the single hardest part of a 5-spd conversion? I have basic mechanical skills, and plenty of more skilled help.
Question #3 - How cheap could I do it? I would also consider a 6-spd from a Z-28/Formula if it is compatible - those are obviously readily available.
Obviously, any recommendations as to potential 5-spd (6-spd) kits would be most appreciated.
For those who have been such a big help before, thanks again!
Ben :banghead:
Melting Slicks
Joined: Mar 1999
Posts: 2,845
Likes: 2
From: Apex NC
Re: should I just do it? (Ben's75)
The swap from auto to manual transmission is not trivial. The fastest way to get the car drivable would be to properly fix the leaking TH400. To swap in a manual you'll need a new pedal assembly, all associated z-bar and rods for the linkages, a shifter assembly and console top plate, a flywheel, bellhousing, clutch kit, clutch fork, new driveshaft, transmission mount, etc. This is assuming a stock 4-speed swap. Custom work for a 5 or 6 speed adds items above and beyond. You're looking at a long term project to do it right.
If the car is truly going to be your main transportation and you need to have it drivable soon, fix the TH400.
My $0,02.
Shannon
If the car is truly going to be your main transportation and you need to have it drivable soon, fix the TH400.
My $0,02.
Shannon
Team Owner
Joined: Jun 2001
Posts: 43,136
Likes: 155
From: Thomson Georgia
Re: should I just do it? (sb69coupe)
The swap from auto to manual transmission is not trivial. The fastest way to get the car drivable would be to properly fix the leaking TH400. To swap in a manual you'll need a new pedal assembly, all associated z-bar and rods for the linkages, a shifter assembly and console top plate, a flywheel, bellhousing, clutch kit, clutch fork, new driveshaft, transmission mount, etc. This is assuming a stock 4-speed swap. Custom work for a 5 or 6 speed adds items above and beyond. You're looking at a long term project to do it right.
If the car is truly going to be your main transportation and you need to have it drivable soon, fix the TH400.
My $0,02.
Shannon
If the car is truly going to be your main transportation and you need to have it drivable soon, fix the TH400.
My $0,02.
Shannon
Le Mans Master
Joined: Apr 1999
Posts: 6,134
Likes: 46
From: Raleigh North Carolina
Re: should I just do it? (Alwyn678)
I'm not one to shy away from a challenge, but I agree with the above posts. It can certainly be done... but you'll wish you didn't spend your lifes energy on the project when you start running short on time.
Also... if you replaced the seal more than once and it still leaks, obviously there is something causing the new seals to fail, or, the fluid is leaking from somewhere else.
Some torque converters have drain plugs to aid in changing out the fluid- check to see if yours has a plug, and if so, make sure it is tight.
If the torque converter is worn (similar to a harmonic balancer being worn)... then get a new torque converter.
Check that the torque converter and the seal diameters match. The new seal should be fairly tight on the torque converter. You may have the wrong converter.
Depending on your method for removal/installation.... don't let the torque converter rest on the seal. If the front pump bearing is loose/sloppy, the torque converter will sag down and ruin a new seal.
Also... if you replaced the seal more than once and it still leaks, obviously there is something causing the new seals to fail, or, the fluid is leaking from somewhere else.
Some torque converters have drain plugs to aid in changing out the fluid- check to see if yours has a plug, and if so, make sure it is tight.
If the torque converter is worn (similar to a harmonic balancer being worn)... then get a new torque converter.
Check that the torque converter and the seal diameters match. The new seal should be fairly tight on the torque converter. You may have the wrong converter.
Depending on your method for removal/installation.... don't let the torque converter rest on the seal. If the front pump bearing is loose/sloppy, the torque converter will sag down and ruin a new seal.
Melting Slicks
Joined: Feb 2003
Posts: 2,330
Likes: 6
From: Long Island NY
Re: should I just do it? (Tom454)
Corvette Repair in Long Island has just done a auto to 4 spd conversion on a '79. Give'em a call... http://www.corvetterepair.com
