76 transmission leak
Thread Starter
Instructor
Joined: Aug 2007
Posts: 124
Likes: 0
76 transmission leak
Hello again..Have a 76 with the TH350 or TH400 (not sure)..Anyhow I have a leak on passenger side of tranny..It comes and goes..It seems to be coming from a 4 to 5 inch "hose" with a clamp on each end...I have looked at my AIM with no luck.When I checked my fluid level it was a pint low..Any ideas?......Thanks,Pete
Le Mans Master
Joined: Apr 2005
Posts: 6,359
Likes: 428
From: Seattle Area WA
I can't thing of any hose on the passenger side of your tranny unless it is up by the radiator, there should be hard lines going to and from your trans case for cooling. Check the below pics. Maybe someone tried a Bubba fix.
http://blog.scottsvettetalk.com/2008...placement.aspx
http://blog.scottsvettetalk.com/2008...placement.aspx
Racer
Joined: Jan 2007
Posts: 385
Likes: 3
From: RTP NC
Check this link out. There may be some info you can use...
http://forums.corvetteforum.com/show...nsmission+leak
http://forums.corvetteforum.com/show...nsmission+leak
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
The modulator on a 4oo is on the right side- could be that it's done and leaking fluid out thru the diaphragm into the hose. Maybe someone put clamps on it?
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
That actually makes a lot of sense. I think you should have a THM350 (unless you have an L-82). The vacuum modulator is connected to intake manifold vacuum via a steel line and a short piece of synthetic rubber tubing. As mentioned, when the diaphragm inside the modulator fails [ruptures], fluid is allowed to leak outward and only the tubing will keep it somewhat sealed. Take the tubing loose from the modulator can and see if red tranny fluid drips out (it won't pour out). If so, you need to replace the modulator, replace the oily synthetic tubing, and clean out the metal vacuum line from the engine. P.S. Be wary of local auto parts store "replacements" for the vacuum modulator; most are chinzy approximations of the original. They'll work...but not that well.
Le Mans Master
Joined: Feb 2000
Posts: 7,032
Likes: 2
From: Newburgh NY
Make sure it's not coming out of the Dipstick tube. I've had to change a number of them (o-rings around the base of the tube) over the years. It's hard to see but if it's leaking near there a flashlight and mirror should help you be certain.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Racer
Joined: Jan 2007
Posts: 385
Likes: 3
From: RTP NC
My hoses are rubber on the Radiator end and steel where they bolt to the Tranny. I have a TH350, not sure what you have but maybe there is a difference between the TH350 and what you have. Either way, looks like those could be leaking but it really could be several things there. It could be the hoses, it could be the Detent cable "o" ring, could be the 1-2 Accumulator "o" ring, could be the dipstick tube "o" ring or it could be coming out of the top of the dipstick tube. You are going to have to clean it really good and go from there... Hope this helps. I had posted earlier with a link, that link has a good diagram/diagrams showing all the areas mentioned above.
Racer
Joined: Apr 2006
Posts: 340
Likes: 0
From: Warrensburg MO
Looks to me like your return line has been spliced with a rubber hose. Sometimes this is done to flush the system at home. I would change out that rubber hose, clean it up, and go from there. Cheers..
Tommy
Tommy
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Cooler lines between the radiator and the transmission are steel. It looks like someone cut the lines coming out of the transmission and put some rubber "jumper" tubes in their place. Check your AIM and parts catalogs to see what you are supposed to have; there should be two steel lines (fluid "out" and fluid "in") to the transmission. I would be really concerned about having synthetic hose on transmission lines.
Thread Starter
Instructor
Joined: Aug 2007
Posts: 124
Likes: 0
Thanks for all the replies...I will clean that up good to start..Any suggestions on a good cleaner?...I have tried Simple Green and other assorted "bottle" cleaners...I have a pressure washer but I know it would be a mess to clean it up on the driveway...(perhaps a car wash)....BUT..I agree I need to change out the lines and make them "all metal from radiator to tranny..I tightened up the clamps around hose on both ends..(they were a little loose)..Thanks,Pete
Racer
Joined: Apr 2006
Posts: 340
Likes: 0
From: Warrensburg MO
Thanks for all the replies...I will clean that up good to start..Any suggestions on a good cleaner?...I have tried Simple Green and other assorted "bottle" cleaners...I have a pressure washer but I know it would be a mess to clean it up on the driveway...(perhaps a car wash)....BUT..I agree I need to change out the lines and make them "all metal from radiator to tranny..I tightened up the clamps around hose on both ends..(they were a little loose)..Thanks,Pete
Melting Slicks
Joined: Jul 2004
Posts: 2,577
Likes: 2
From: Long Island New York
Cooler lines between the radiator and the transmission are steel. It looks like someone cut the lines coming out of the transmission and put some rubber "jumper" tubes in their place. Check your AIM and parts catalogs to see what you are supposed to have; there should be two steel lines (fluid "out" and fluid "in") to the transmission. I would be really concerned about having synthetic hose on transmission lines.
That is not factory, someone's been under there and did a Bubba repair. You need to buy the original steel lines that go from your trans to in front of your cross member. The rubber hoses should only be from the radiator to the steel lines in front of the cross member running vertically. I bought my new repro's from Corvette central for about $60.00.
