Imperial Transmission Leaks & How To Fix Them

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Question from Elijah:

Has anyone repaired a leak at the seal where the shift linkaged enters to the housing of a Torqueflight? I'd appreciate any tips or guidance before I dive into this.


From Steve:

We have a nifty tool at our shop that saves alot of work replacing the selector shaft seal. All you have to do is remove the two levers on top. The tool then screws into the seal, a set screw in the top of the tool is then tightened down extracting the seal. A driver to install the new seal is also included. Otherwise the transmission valve body must be removed to drive the seal out from the underside. I'm pretty sure the tool is made by the KD Tool Company. I can look tomorrow and check for sure.

The tool is made by K-D Tools and the part number is 2392. There are two pieces to the tool, a puller to remove the old seal and a driver to replace it. Used it dozens of times and it works real well. You should be able to order one at any larger auto parts store.

From Frank:

Here are some details on the repair for the side case seals on a Torqueflite where the shift shaft comes up out of the case. I am fairly certain that the seals (2) are still available from NAPA. They can be cross referenced to napa numbers. I will list steps for the job:
1. raise and secure car (safety first)

2. remove pan and drain, remove filter

3. on side above pan rail, remove pinch bolts securing shift lever and kick-down lever and remove levers by pushing up-ward.

4. remove 8 or 10 7/16 head bolts securing valve body to case and lower slightly, being careful with right side on account of spring that is held up by the body (you can't see it till body starts to come down)

5. on left side, remove e-clip holding park shaft to lever, valve body should now come down, leaving park shaft hanging

6. seal is now visible where shift shaft went up through the case, a small screwdriver and hammer will tap it up and out

7. new seal can be drawn down into case with about a 1/2 inch bolt & nut and some large washers till fully seated.

8. on shift shaft on valve body, 2nd tiny seal is located under e-clip at the top of the shaft, remove clip, pick out seal, install new one
paying close attention to old one so the new one goes in exactly the same way

9. lube the case seal with drip of tranny fluid before reassembly

10. reverse this procedure to reassemble... this is not a complicated job, just be careful

The napa seal numbers are 8017 for the case seal and 1-3308 for the small seal on the top of the shift shaft under the e-clip & washer.
I see that Steve has posted that there is a tool available to replace the case seal without removal of the valve body. Hopefully that will work for you as it will save a lot of time. Just be certain that the seal goes down flat to the case and not crooked as it will leak. Sometimes the clearance to work down at the side is not to good.

From Mikey:

SPX Miller tools should have the various torqueflite tools listed online, I know they did at one time. In addition, fwiw, over the years I have found a few very good references to supplement the FSM for working on these things, so in no particular order here are some of them for you folks who may want to do more than just change a filter and fluid now and then.

ATSG ( automatic transmission service group ) makes a good booklet form for the 727 and 904, probably cost 10 bucks from your local transmission rebuilder or check it out online.

Motors Automatic Transmission Repair...these are great but they cover everyone's transmission, and so you end up with a 60 dollar (or more now, since I've had mine forever) book that you may only want one chapter out of.

National Service Data - they are year specific generally but they cover the general service stuff as well as more in depth repairs, but again they will be like Chiltons and cover every car for that year. Unlike Chiltons, they actually give you useful information!

On ebay, I found a HP books titled " torqueflite a-727 transmission handbook", so I decided to potentially throw 20 bucks out the window and get one. I highly recommend it. Gives a lot of the theorhetical, the practical, general service data, what year spans of parts were the same...and theres a LOT of them, sub assembly repairs, how to rebuild one, how to modify one, etc etc etc.

BTW, I have found that you can generally remove shift shaft seals with a couple small picks and some finesse, and a 15/16 socket will work very nicely to reinstall it with. Just be sure you get it started squarely. Given the relative ease they pop in and out and the fact that theres no pressure against them, nobody should be afraid to R&R one of them.

Question from Kaleigh (1958):

I am having a little trouble with the transmission shift cable. The cable on my car is not broken but the outer cable at the transmission is made out of rubber pipe and is perished and broken. Probably burnt from the exhaust. When the car is parked it leaks transmission fluid.  I was wondering if this is a common problem and has happened to somebody else and they may be able to shed some light on the subject, in the way of, does this tubing has to be oil tight or is it a problem further on in my gearbox?


From Phil:

If your 58 is like most pushbutton Torqueflites, I'd say the O-ring seal where the cable housing goes into the transmission has gone bad or hard. I think the outer seal you see is just a dust/mud shield, the actual part that seals the tranny fluid in, is the O-ring on the housing where it enters the transmission.

From Philippe:

The problem doesn't come from the rubber cover of the cable but surely from the "o" ring which is on the control cable adapter in the cable housing. You have to remove the cable from the adapter then remove the housing (there's also a rubber grommet at top of it) and check the "o" ring on the cable adapter. It's a common problem on Torqueflite: when you have a "drain back converter" (after some days w/o running the car) the oil level is high in the pan, higher than the pan, and you've got leaks from different areas as control cable, neutral switch, rear of the transmission. etc.

From John:

If the 58 cable is the same as 60-64, & probably is, there is an O-ring on the end that goes into the tranny, This is usually a source of leakage. I'm not certain, but I don't believe the housing is the source of the leak.

Question from Bill (1959):

When I cold start my '59 Imperial, and rev it, I get transmission fluid coming up through the dipstick and spraying onto the exhaust header. Has anyone else out there had this problem? Does anyone have a cure?


From Philippe:

Exactly as mine when the engine has not ran for several days!  I've overhauled the transmission some years ago and the problem went only after that!! I think I've found why: no hole in the gasket for the transmission breather (which is at the rear of the transmission, see

You have perhaps a clogged breather? When the car sat for some time, there's a converter drain back so the oil level in the oil pan is higher than normal (take a look at your oil transmission dipstick..). When you start the engine there's some pressure built in the transmission (because there's too much oil) and if the breather is clogged, the oil escapes from the oil tube (and flows onto the exhaust). To cut this hole in the gasket I have to remove the transmission extension (+ miscellaneous parts like the hand drum, propeller shaft, etc..) so I'll do that later.  At this time, I've removed the dipstick and slipped 3 feet of plastic garden hose onto the dipstick tube.  As this hose is clear I can see the oil goes into it, then returns immediately in the transmission. And the more the engine revved high (hot idle), more oil "climbs" in the hose!

From Roy:

Usually when this happens on any Automatic Transmission, the VENT is clouded or the filter is drawing AIR, not sealed well and the gasket is leaking air.

Question from John (1961):

We just got the torqueflite working again, with some TransMedic. I know this is only a stop gap measure until I get the transmission rebuilt, but at least it is now shifting smoothly. Funny thing though, the transmission seems to leak 3 times more now since I added this product then before. Supposedly this product also helps to stop leaks, not promote them.

Hopefully after I get the transmission rebuilt it will perform much better and I won't have all of the problems I've had. After all of the transmission woes lately I'm about ready to toss the automatic out altogether and put a tremec 5 speed manual in the car!

Reply from Rob:

If followed the story of the difficulties of people on the Mopar Mailing List putting the Keisler Tremec "bolt-in" kit in their Challengers you would be praising your leaky torqueflite.

Question from Bill (1964):

The transmission in our '64 leaks like crazy around the shifter (vertical) shaft. Does anyone know if that seal can be replaced without removing the oil pan? The shaft wobbles a bit too, is it supported in any kind of bushing?


From Ken:

That’s whats leaking. No, you have too remove the pan.

From Frank:

I think the only way you could replace the seal, without removing the pan, would be to have the tranny out of the car so you could access it. Taking down the pan and valve body would be easier if the tranny is in the car. I've done several 727's this way and it's not too bad of a job.

From Paul:

Pat Blaze sells an external seal kit for aluminum case Torqueflite transmissions. Most of the time there is more than one seal causing the trouble. I have purchased these kits for two of my cars and had them installed at a local transmission shop. The leaks stopped.
I have been told that this is caused by fluid from the torque converter seeping back into the transmission case. The increased volume raises to levels where old seals for the neutral saftey switch, shift cable, and other things have dried out.

The kits cost about $40.00. When I had them installed at the transmission shop, they also serviced the unit so the cost was right around $200.00. Pat Blaze also provides instructions on how to install the seals yourself. His advertisement is in the National WPC Club News.
He doesn't sell kits for the old cast iron style.

From Kent:

I can't recall if I passed this on before, so I will do it again. The transmission in our '67 Imperial was leaking badly especially after it was parked. Transmission worked fine otherwise. I sent out an email or two for advice and got on the chat line too. Some said it might be a seal leaking where the control levers come out of the case. I finally got it up in the air and went to work. The top and side of the case was dry and no indication of any leaks anywhere noticeable. I decided to drop the transmission pan and service the tranny. Presto, since then it has been just fine. No leaks and shifts smoothly as before. The old pan gasket didn't look bad but apparently it was. Maybe it loosened up after years of compression and heat. I also pulled the inspection plate and drained the torque converter in process. Anyway this turned a gloomy picture bright as I didn't have to pull the tranny out to repair it at this time.

Question from John (1965):

The transmission on my '65 has a transmission leak. I put a new gasket & filter on her but it continues to leak. Is there someplace else it could be leaking?


From Joe:

Check the rear seal and also the cooler lines that run from the transmission to the radiator and the radiator also. A good way to check the rear seal is to prop the front of the car on jack stands for a day or so.

From Eugene:

My '65 had a leak problem which I wrestled with for some time. There is a possibility that the leak is from the area where the shift cable enters the tranny , it could be from where the park cable enters the tail shaft housing (or its gasket) or heaven forbid it could be what I ran in to.----a CRACKED case.. I hope yours is one of the others reasons.

From David:

Yes! About a dozen! But the most common, in order of frequency, are:

1. Tail-shaft extension housing seal (where the drive shaft comes out).

2. Transmission cooler plumbing (The 5/16" steel lines that run from the left side of the transmission case to the bottom tank of the radiator) due to rust and/or chafing on something under the car (buy some EL CHEAPO plastic or rubber tubing hangers).

3. Transmission front seal. You will have to remove the steel inspection cover on the lower half of the front of the trans case where it bolts to the engine (not a big job) and using a flashlight or drop light, face the rear of the car and look behind the flex-plate/ring gear. If it's wet, and the stain is reddish-brown, then the trans will have to be removed (this IS a big job for novice) and the seal replaced. BE CAREFUL HERE! If the stain is shiny jet black, then this is NOT the trans leaking, but the rear seal on the engine itself. You'll have to remove the trans to repair this leak also, but that won't fix your phantom trans leak!

4. Dipstick tube O-ring. A real no-brainer to repair. Remove the bolt from the tab that holds the tube in position and carefully work the tube out of its' hole. Hit the local Parts Barn and get a new O-ring. Install the new O-ring and wet it with a finger full of trans fluid, then carefully work the tube back into its' hole and re-bolt the tab. CAUTION!... Before disassembling any hydraulic system (auto trans, power steering, brakes, etc.) make sure that you thoroughly clean the area to be disassembled first!

If you've ever seen a hydraulic "clean" (assembly) room, you'd find that it's cleaner than most hospital operating rooms! Hydraulic systems hate dirt! Keep it clean!

This is a very rare occurrence (the O-ring I mean) but has happened when either the tube was removed and the bolt not replaced after re-installing, or when the tab has been broken off the tube. Both conditions allow the tube to work in the hole while driving and every time the dipstick is pulled to check the level. This wears out/tears the O-ring and it won't seal. Rare, but at least it's easy to fix.

From Paul:

Have you checked the seal at the output shaft?

From Joe:

Check the shaft seal on the shift linkage. This seems to be a common source of leaks. Also some of the backup light switches can develop a leak.

From George:

A Torqueflite can leak from a multitude of places, the pan just being one of them. A common leak point is the dipstick tube o-ring, and the speedo gear o-ring. If those are dry, It could be the front or rear seal. If the fluid is coming out the bottom of the bell housing, it is most likely the front seal. If it is coming out of the rear of the case, around the universal slip joint, it is the rear seal.

All of the seals I have mentioned, with the exception of the front seal, can be changed without removing the transmission.

Question from Rich (1973):

My '73 has develop a transmission leak. I had the fluid changed with a new pan gasket. The leak is still there, and I'm wondering what the list thinks of "Trans X" to stop leaks. The mechanic I go to said the torqueflite "727" was a great transmission, and he has had good success with "Trans X."


From Paul:

I can't say if this is the problem with your car, but Torqueflites from '62 on that leak often can be fixed by installing the seal kit available from Pat Blaze in Monroe, Washington.

When the cars get old, the torque converter shaft seal allows fluid to drain back into the transmission after the car is shut off. The fluid in the transmission case then begins to rise, and eventually overflows out through some of the places where the seals have dried out. This can be where the shift cable enters the transmission, neutral safety switch, speedometer cable, etc.

The problem can be eliminated by replacing the torque converter seal, but I have found that the "easier softer way" is to purchase the seal kit and have it installed. If I remember correctly, it costs about $30.00. I have done this to my '62, '63, and '65 Imperials with total success. This kit is not available from him to fix this problem in Powerflites of early case Torqueflites.

From Phil:

Where is the leak? All of us are quick to assume the front seal has failed in an old car but that may not be the case. I solved my 73's problem by replacing a $4.00 selector shaft seal.

If you can, put the car up on stands and spend some time inspecting the trans. Remove the torque converter cover and look inside the housing for dripping fluid to confirm a front seal.

From Rob:

I have heard good things about Trans-X. From some people that should know. Personally, I never tried it and it always sounded like snake oil to me.

From Steve:

Very seldom will something in a can fix anything mechanical. Depending on where your transmission is leaking with the exception of the front converter seal, the leaks can be repaired from the outside of the transmission without much disassembly. Take a good look at your seal under the shift levers on the driver's side-have replaced alot of them.

From Dave:

I would be a bit "leery" of "Trans-X". One of the reasons it "works so good" is because it contains a lot of stuff that aggressively "attack" seals etc (thus the "cure" seems to arrive quickly, - or at least the leaks stop quickly.

Do a search for "transmission additives", and you may find a site that lists many of the ingredients in such products, and also the percentage of same in many of the different brands.

I do transmission repairs here a lot, and the only product that I have found (and that I will use) is made by "Gunk"/Solder-seal", and is called M15/12. This stuff works (although rather "slowly" in some cases), - but I can tell you from personal experience that it will NOT "hurt" the transmission. The problem with the more "aggressive" products is that although the work the same way (by "softening/expanding" the rubber parts in the transmission), - some of them do not know when to quit, and will just keep expanding the rubber stuff until it "explodes". Then you have a real problem. A lot of leaks occur in cars that "sit" that if the cars were "used" everyday, - would have viortually no leaks at all. This is due to the fluid in the torque converter (eventually) draining back into the pan, - the now extra-high level of fluid can then find it's way to places where it would not normally be if the car were used more frequently. Some of these "places" are the seal where the valve body goes through the case (where the shift levers are attached), - I have had to replace a LOT of these seals, in the case of cable-shifted transmissions, - the O-rings on the cables will almost always leak when the fluid level in the pan is very high. The rear seal (output) may leak also under these circumstances, yet never leak if the car is driven often. Another "trouble spot" is the O-ring located on the reverse band strut shaft. This puppy will leak, and you would swear that the pan gasket is at fault, - but after 2 or 3 pan gaskets have not fixed it, - you can bet that's where the leak is. Easy enough to tell, - at the back of the case, - there will be a small "depression", and if you look carefully, - you can see the shaft (it's about 1/2" in diameter). If the O ring is leaking, there will be fluid accumulation in this depression, - if no fluid here, - then the O ring is not leaking. Since this depression is right above the pan rail, - it looks for all the world like the pan gasket is the problem.

As for a "front seal leak", - note that rarely (if ever) will this seal leak unless the engine is running (and the shifter in some position *other* than "Park" (does not apply to cable-shifted units). You can get fluid from the bellhousing area without the engine running, - but that leak would be coming from the pump cover O-ring (or out of the pipe-plug for the kickdown band shaft). Pump cover O ring leaks are fairly rare, - I have taken 727s apart that had NO O ring here (someone forgot to install it), but had no (or at least no *complaint* about leakage), - so what does that tell you? It tells me that the car gets driven every day, and there is not much fluid in that area to leak out to begin with.

From Mikey:

There are several leaks that can be easily addressed in a TF without dropping the trans: Oil pan, rear seal ( where the driveline goes ), shift shaft, kickdown lever,disptick tube, the little gasket where the plate is that covers the snap ring on the output shaft - seldom noticed as often the crossmember is in the way , and the little gasket where the neutral safety switch mounts. If I had a leak at ANY of these, I would be more inclined to fix them than to just add Trans X. I have used the stuff, its basically Rislone or Alemite CD-2 for your trans as opposed to your engine.

As far as the common malady of torque converter drainback , where the converter drains back into the trans and overfills it, its a transient thing and if the trans is sealed well it shouldnt cause huge amounts of leakage. Once you restart the car, the fluid is pumped back into the converter where it will stay unless you have a prolonged shut off period.

Besides the parts that Pat Blais sells ( btw, if youre in the Northwest hes probably the best TF guy for parts and service - and no I dont work for him ) there are some parts from Trans-Go that address the drainback issue as well.

As far as the person who asked about parts or repair interchangeability and commonality, the main changes that occurred in the TF were going from cable and pushbutton shift to the mechanical rod linkage in the column or floor shift cars, the change in the speedometer gear and cable around 63 (?) , the removal of the rear pump I think was in 65 , the torque converter spline change and input shaft change was after that and there were more minor internal changes as the trans evolved. Most of these changes wont affect any of the basic do it yourselfer kind of things such as gasket or seal changes or basic trans servicing.

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