Well guys I am looking for any insight here. last night I am driving around and when I get about 10 miles from home I feel the tranny starting to slip. It was not too bad at first but got worse quick. When I was about a mile from the house I could barley get the car up to 20mph. I get it home and in the drive way. fluids looked good and were at the right level.

The car is original and the 350/350 ran good when I purchased them but both leak and are really untouched. Motor compartment and undercariage show there age as she has leaked for some time.

My question is how do I know if it is the torque converter or ther tranny itself? Reverse works and grabs like it should. What else could it be? Any tips besides pulling the tranny? Although the tranny leaked a good amount of fluid the level never got low.

 

Does the fluid smell burnt and look dark brown? It should be red and transparent. Its hard to believe that is leaks but does not show a loss of fluid at the dip stick. Are you checking it in neutral with the engine running?

 

Man that sux - sorry to hear! I am now having concerns of mine doing that!
Does L and S give the same problem? I heard those are supposed to give higher fluid pressures...

 

Thanks Pat, I will have to check and see if the fluid is transparent and red and if it has a burnt smell. If it does smell burnt what does that indicate may be the problem?

Thanks Rob. I pulled it out of the garage again after it sat to see if it was magicly fixed and it will not grab in S or L so in all of the forward gears is is really slipping. When you put it into drive you can feel the tranny engage like it should but it just does not have any grab to it.

 

Time for a rebuild.

 

Time to fire your mechanic elves and hire some who will work!

I did not want to be the first to say that...

How many miles do you estimate on the tranny?

 

Rob, Funny you did not want to be the first to say rebuild as I did not want to hear it

Thanks Andy, So since I do not know a lot about transmissions could it be the torque converter and not the tranny itself?

 

No way it's the converter. Time for a rebuild.

 

The dreaded "R" word again...

Sounds like the internal bands could be gone. Not a nice thing that it is a "all of a sudden" failure!
Any way to check those without pulling the tranny? (I have a feeling the undesired "N" word is coming...)

 

Hey guys, just another question. Would the tranny really fail all at once with no signs? just all of a sudden start slipping?

i am just thinking that wouldnt it give signs? What would the car do with a shot torqe converter? What if the filter was clogged? Would that restrict the pressure needed?

Or do tranny's just fail without warning or noise?

 

Something let go. If the fluid is at the right level and it slipping its toast. Sounds like a good excuse for a 5-speed transplant to me.

 

Richard, I wish a 5 speed was in my budget...as well as a high HP motor but that is not in the cards at this point. Just hoping that maybe it would have been somthing cheap and easy as I just got the car back on the road. but oh well. I was thinking of putting in a used tranny and rebuild mine later when I do the motor.

Is it better to do the rebuild on the tranny at the same time as the motor to match them or does it not matter?

thanks

 

Here's your BIG/HUGE clue that it's not the torque converter. It goes into reverse.

 

Right. It still means the front pump is working, too, and you have main hydraulic pressure.

The manual suggested the forward clutch, which to me its failure should have been gradual, as it is built like a motorcycle clutch.
Of course whatever engages it could be at fault.

It also suggested the modulator, which I think is on the outside of the tranny, or a clogged internal passage.
Has this thing been rebuilt before or modified with a shift kit or anything?

 

Some wrecking yard put limited warranties on there used transmissions. Best bet is to have yours rebuild then you know what you have plus you get a warranty.

 

No, It appears to be all original but I can not say for sure. SO a clogged passage or a modulator may be to blame. Those may be cheap enough to try before pulling the tranny out.

Randy, thanks for the info as to why it cant be the converter, That makes sense and thought about that but was not sure

My dilema is that if I pull the tranny I am going to want to pull the motor as well and do a performance rebuild on the motor and trans but do not want to have the car tore apart for the time frame it will take me to finish it due to funds set aside for the car.

Another thought was to just drop a BB in with a 400 trans and get the desired power a lot cheaper than building the 350 to get to 375ish (correct me if I am wrong) But I like the fact that I have original motor in there and would like to keep it that way but get the desired drivability and power to maybe get close to the BB numbers and not spend a fortune....but that is allways the trade off, $ to HP ratio If anyone had to throw a rough guess as to cost to have a 72 350 get to 375hp? Should be able to find a 70 455 and trans for less than a grand I would think. But then again the 70 350 was at 325HP so getting to 350-375hp changing internals should not be to tough....

Anyways I am pretty sure it needs a rebuild as well and believed that before the thread but was hoping not as it opens the door to too many other options....which all revolve around power and that stupid green paper it costs to get it

 

Can't the tranny be pulled without the removing the motor?
This would at least postpone any thoughts of doing anything with the motor.
Sometimes you just HAVE to put the blinders on the horse...........

 

That is a great way to think about it Rob. Yes the Tranny can be pulled without the motor atleast that is what I have been told and heard ( I learned that after I did the last one lol ) I thought the convertible cross member was fixed and welded but have been told that they are bolted just different then the hard tops ( I hope this is correct)

I allow myself to get carried away, just like the interior project. Maybe it is time to just put on blinders and focus on just tranny...but my fear is that whatever I do to the trans may be wasted money if the plan is to maybe go BB or a 350 build and the tranny will not be matched to the motor and have to do it again or would it just be a matter of changing the converter at that point?

maybe I will just sell my Torque thrusts to fund my 350 build and put my stocks on

 

Pat, I did get the car to the office in bothell a couple times but did not have the time to get ahold of you to see it...Want to come pull a tranny and get to see it in the garage lol

I think you are right about the rebuild and warranty, What is the opinion on the rebuild and use my torque converter and then upgrade the converter when I do the engine build?

 

It doesn't cost alot rebuild th350. I would replace the tq. conv. at the same time.

To remove the transmission first thing take off the dist cap. The engine will tilt back when the transmission is removed. Get the car in the air. You will need four jack stands.

I would drain the pan to make it a little easier to handle.

Tq conv. bolts will have to be removed. You can bump the starter with the key (keep your hands clear of the fly wheel) or use a pry bar to turn the engine.
Then remove the drive shaft.
Next the cooler lines.
Shifter cable, linkage, and vacuum line.
Kick down cable from gas pedal arm.
Top four bolts that bolt the engine and transmission togather.
At this point you will want to have jack under the transmission. A floor jack with a piece of 1x6 wood about 16 inchs long will work.
Next remove the crossmember and the bottom two bolts for the engine and transmission.

Yes the crossmember is bolted in with two bolts on each side.

Things you will want to look at to see if they need replacing are u-joints, and cooler lines. With out a doubt you will want to replace the transmission mount.

 

Maybe consider building your troubled 350 to handle big HP, so it will be BB ready. Or, find a 400, build it instead, and put it behind the 350 motor for now (if they bolt up the same)...

 

It will bolt up. You will have to move the transmission crossmember back. Holes already in the frame. Two things that will have to be switch is the drive shafts are different lengths and the e-brake cable.

 

And the yoke.

 

Thanks for the input guys, I think the path is playing out. Not the least expensive path but looks like just rebuild the 350 trans and at some point a decent 350 motor build. the only thing that I am not 100% satisfied with about my car is power. I do not think a 350 build will get me to where I would like to be especialy considering cost compared to a BBO but I believe the trade off is keeping the og motor and a 350 can be fun and with gears feel great but hard to compare to a BBO (Although I have not driven one) All the cars I looked at and drove were SBOs. So it will all come down to what type of costs would it take to get the 350 motor to stock 70 BBO like specs if even possible....any thoughts on the possible costs....I know high HP 350s are out there and not sure if 350-375ish is even considered high HP or not or the cost to get there

 

Before going too far, check the vacuum at the modulator to see if it correct. It should be off the manifold vacuum. It might be possible that the hose broke or fell off. If that is ok, you may want to drop the pan and inspect. Another approach to narrowing down the culprit is to remove the valve body and use compressed air to check the internals for proper operation. The forward clutch should have a passage that you can shoot air into and check to see of it operates the clutch. You won't be able to see the clutch, but you should hear a clunk when it gets applied. If this works then your valve body may have a stuck forward clutch apply valve. After all of this, then it is time to gut the box. Converter and pump are probably just fine as
Reverse takes more pressure to operate than drive ranges.

 

well i got the car up and the vacuum line is good, getting ready to pull the pan here in a little bit. When the car is started and you shift it into drive, it engages like it should and you feel it is in gear. Same thing in reverse just reverse does not slip like the forawrd gears.

The underside of the car is covered in years of leaky fluids and grime from the motor and trans. I noticed that there is fluid sprayed all over above the ujoints on the drive line close to the tail shaft on the tranny and thought it was weird as it is right where the ujoints are but they dont hold fluid like that

Any other suggestions?

 

Ok, Trans pan removed and besides nice red fluid there is really nothing in the pan, not alot of shavings and no objects. I am going to hook a vacuum gauge up to where the line goes to the modulator and see what I have.

Do tranny's give out and just slip with no notice and history or just it have been a progressive failure?

 

Sounds like the rear transmission seal has gone by by

 

Yep. Fluid leaks out and is slung around off the U-joint, causing the spray pattern you see. My ford does that but surprisingly leaks very little (like a cup per 10k miles.)

I figured you would have had some early indication of failure. I could be wrong of course.
When you drove the car last, how did it shift? Firm and on time or did it feel slow or mushy?

Hope you get her fixed soon.

 

Thanks Rob.

The car shifted fine like it always does. Before I take out the tranny I am going to take out the valve body and clean it out, change the filter and the fluid and see what happens, maybe I will get lucky but probaly not.

Is there any solvent or anything that I can let run from the dipstick down throug the open tranny with the filter removed to help remove any unseen debris?

 

I thought the dipstick tube went right to the bottom of the pan. I figure it would be just like pouring clean fluid right into your bucket underneath.
Of course I never had a tranny apart though............

 

I wouldnt waste any time pulling the valve body to clean it...

You are in denial...Sorry...you know what the right thing to do is.

Do it once and you will be happier...pull the trans and take it to a shop...rebuild and replace the converter...flush the tranny cooler and lines then add an inline filter.

 

Rob, you are right...Do not know what I was thinking (obviously wasn't)

442Scotty...You are probaly right that I am in denial and really hung up on the notion that maybe somthing else is wrong. To me, and I am no expert and do not have any expirience but I would think that there woule be signs leading up to failure....And before I pull the trans I just want to be sure. Maybe I am wrong and they just do go bad with no signs in a few miles and that is what I am trying to figure out. Most times you hear that people have signs that the tranny needs to be fixed due to issues that are getting worse, or they blow the tranny up. But when mine started slipping I left a stop light and within a few miles the forward gears would not grab.. I also just want to make sure I do not jump to the rebuild conclusion unless that is really what is wrong and just trying to trouble shoot it first.

maybe my lack of knowledge with transmissions is skewing my thought process, but if the valve body was clogged would it cause the trans to slip? what about a clogged filter or bad modulator? If those are not possible then I have my answer and I ask only because I do not know.

 

Dude, I would feel the same way. I would think there would be warning signs, too.
I like taking my car on long trips, so this is concerning. Guess I need to plan a preventive rebuild some day...

 

I've had a few transmissions go over the years and they usually give you no warning. My GTO trans started slipping out of the blue and in less than a mile it wouldn't even pull the car anymore, luckily it was less than a mile from my house. Seen lots with no reverse but then you just learn to park on hills.

Dude, you could of had that blown trans rebuilt and back in by now.
Do yourself a favor and rent or borrow a transmission jack , saves having to lie on your back to take it out and put it back in with your belly.
Going by some of the big bellys I see on guys anymore you would need to have the car on a lift for them to crawl under it with a trans balancing on their gut.
If I'm offending anyone... if you can catch me you can sit on me.

 

Blue, have you been spying om me naw, my belly is not that big. You have a great point though as to this could have been done by now and I can not argue that. I guess I will go pull it and get it back on the road and worry about upgrades and other things later....

 

Check the vacuum at the modulator first, then check the modulator with a vacuum pump. If it holds vacuum chances are the modulator is good. The valve body may still be the problem, but the only way of checking is to apply air to the forward clutch port.
A good trans shop could do this, especially if you really think the problem is not a major part. My C4 ford transmissions showed their problem when cold, not hot. They would slip till warmed up, then grab just fine. Problem was the forward clutch seal had hardened and needed to be heated up to gain some sealing power. Some transmissions have external ports to check oil pressure, but I don't think 350s do.

 

Advice...I have a lead on a rebuilt trans with converter and shift kit from a 69 lemans. Clean unit and will be easier than having mine done and less time and money. Any thought on this? i will keep the og trans and figure it out later when I figure out the motor as to rebuild the SBO or go BBO.

Thanks

 

If that '69 LeMans transmission comes with a warranty, and there's a good shop standing behind it, then it may save you some money over a rebuild of yours.

However, I'd want to know more about that converter and shift kit. The converter has to be matched to your car's engine, weight, gears, and intended usage. And there's a variety of shift kits out there; you don't want something too aggressive.

 

got some more info and this is what the seller states

"its all stock with mild shift improver kit and a little bit looser than stock converter"


I do not know what is meant by "looser then stock" Any clues?

The trans was out of a 69 lemans 4 door