Imperial Transmission Fluids


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Question from Dennis (1953):

I have a question about the proper fluid to use in my '53 Imperial transmission.  It is a PowerFlite and I have drained it. The manual calls for Type A, but that is no longer available. Will the new multi-purpose fluids work or should dexron 3 be used?


From Phil:

I'd heard of Dexon being used in PowerFlites with no problem. One thing to remember, these old transmission didn't have the strict requirements for fluid that these newer transmission have. I've also heard that Type F fluid will work, but will affect shift harshness, which may not be the thing you'd want on a smooth vehicle like an Imperial. Then again, any port in a storm! Most of the newer fluids are superior to the older fluids in both stability as well as lubrication, I'd just use Dexon.

From Paul:

Type "F" should not be used in any Chrysler automatic. I am not sure what it will do, but it does make a difference. This should never be a problem, though, since any place that carries one type also carries the other.

From Marty:

I had my tranny rebuilt 15 years ago by a mechanic in New Jersey that specialized in old Chryslers. He told me to only use Type F fluid. I have never had any problem with the tranny since, and that was 40,000 miles ago.

From Bob:

Chrysler had printed a publication in the early 80's re automatic transmissions with discussions on the proper fluids.

One part talks about Type A, suffix A fluid, which they said is good for older cars, but it was replaced by Dexron; later, Dexron was replaced by Dexron II; they said it was much better than Dexron.

Here are some fluid characteristics that they talked about:

Type A is considered obsolete - is used in racing, only. It is very durable, "slippery", has strong oil molecules and has excellent cooling properties.

Dexron and Dexron II - Very slippery, low detergent properties, is a multi purpose fluid, low viscosity index, very durable and excellent cooling properties.

Type "F" fluid is very sticky, moderate cooling and lubricating properties, recommended for fast clutch action, and has no friction modifier. Exclusively developed for Ford.

Since the early 80's, at least two fluids are recommended now, (for Chrysler cars), and they are fussy about what you put into the transmission; since we're talking older cars here, the above should be useful.

Question from Rob (1955):

What would be the best kind of transmission fluid to use in my 55. I see Dexron II and III but they don't say Chrysler specifically. Also Power steering fluid, I remember it being kind of yellow not red like tranny fluid. What was designed for the Car, and is this still available?


From Dick:

Dexron/Mercon is the closest equivalent you can find today, and it is fine, in fact better in some respects than the old original whale oil derived product, which was yellow in color.

I should have specified that this (Dexron/Mercon) assumes your manual calls for "AT/AQF" or "Type A" Transmission fluid, not motor oil, which some early Chrysler products used in their first automatic transmissions. I think in 1955 they had gotten over that phase, but you should check that.

From Joe:

I have a 1956 Imperial. I changed the fluid and filter 12 qts. I called two different transmission shops. One was owned by and older mechanic. He told me Dexron 3. I then called another one. This individual also told me Dexron 3. 

Question from Remco (1957):

Can someone tell me what transmision fluid to use in my '57? I am told to use F type M type and dextron. I am towing a 6000 pound trailor. Is that making any difference?


From Ken:

With Chrysler transmissions, use dextron 2. Also, have a large tranny cooler or you will cook the fluid.

From Roger:

I'm using dextron II in my '55 Imperial and it seems to be OK. The original trans fluid is no longer made or readily available in our area.

From Paul:

I am also using Dextron II.

Question from Bob (1958):

The shop manual and the service manual for my 1958 LeBaron say to use "Type A" fluid in both the transmission and power steering pump. Our local parts stores only stock Dextron, Mercon and type F. Was type "A" superceded by one of these?

Reply from John:

The DEXRON is the one you want to use.

Question from Cliff (1967):

What is the recommended transmission fluid for my 67'? (I only found notes on a '58 in the archives).

Recently I had my transmission filter changed, and now I have noticed some slight slippage under harder acceleration? I am assuming it's the fluid, as I never had slip before...?


From Dave:

Dexron is fine (and most likely that's what they put in it). No way should it have an adverse effect on the transmission's shifting characteristics though. Did they check the "kickdown" linkage adjustment? Did they adjust the bands, - or just change the fluid & filter? There is a difference between a "transmision service" and a fluid & filter change.

Does the trans slip under FULL throttle acceleration?

From John:

You should be using Dexron or Dexron/Mercon. I would try changing it if you suspect that wasn't what was used. If the trans was a lot of miles on it & the fluid never changed, changing it could cause problems to start, even with the correct fluid. My daily driver Fxxd had 190,000 miles & I wanted to have the trans serviced. The service manager told me not to even think about it. Doing so could potentially kill it on the spot was what I was told. My sister once owned a '67 Polara & a mechanic friend told her pretty much the same thing.

From Paul:

I'd be looking to find a reliable transmission man.

If changing the fluid ruined the tranny, it needed to be rebuilt anyway. If the wrong fluid was used, changing it to the correct fluid should take care of it, as long as it wasn't driven much.

I am not sure how this got started, but I have never heard that changing the fluid will ruin the transmission. Leaving fluid in for too long after it has been hot can cause problems, but these problems should not be made worse by servicing the unit.

One of my Imperials had a bad tranny when I bought it. The car had been overheated while pulling a trailer over the Grapevine. The owner drove it until it quit. The engine was ruined, but was made to run. The transmission was cooked. I had the engine rebuilt, and managed to keep that old tranny going for two more years by having it serviced frequently. Finally, it would no longer go into reverse, or high gear. While it was sick, the fluid would turn dark every 5,000 to 10,000 miles. When that happened I would change what I could without draining the torque converter.

I'll admit that this is an extreme case, I just don't see how changing the fluid could hurt the unit. After a certain number of miles, the transmission is going to wear out. It can only last for so long. Premature failure is usually due to lack of service or catastrophic events.

From Rob:

The story (old wive's tale?) I heard was that if your transmission fluid had never been changed and you didn't have any trouble with it DON'T change it. The reasoning was that the new fluid would "flush" the transmission and cause leaks. Sort of the way some of you advised against an engine flush on a high mileage car. I never heard about it causing slippage though.

From Dick:

Well, I'm old but I'm not a wife, and I may have started this friction fiction friction.

What I said was that if one has a car which still has it's original transmission fluid, and if the car was built while the old Whale Oil based fluid was in use, then don't change it unless there is some problem with it. The old whale oil based fluid was great stuff, and made the transmissions designed to use it work best, better than the new "equivalent" vegetable oil based fluids made today. The changeover was made sometime in the late '50's -so the '67 would have been originally built with fluid very similar to today's Dexron/Mercon. The modern fluid has better anti-foaming properties, and probably resists damage from overheating better, but friction characteristics are supposed to be the same.

I've had quite a bit of experience with old Ultramatics, rebuilding them and servicing them as I ran a Packard service garage for about 20 years - I always advised saving the original fluid and re-using it unless it was burned or dirty. Transmission fluid does not wear out from use.

The only significantly different fluid around is type F fluid, used in some Ford, Studebaker and Jaguar transmissions. This has different friction characteristics, and was sometimes put in the cars to make them shift more rapidly and with less slippage. This could be desirable if the transmission is used for racing or I suppose if there is slight slippage developing, to nurse a few more miles out if it.

From Michael:

The phenomenon of transmission failure closely following a fluid change in a neglected unit is no wive's tale. You'll have a hard time finding a service facility that will do the service on such a vehicle without a signed disclaimer of responsibility from the car's owner. Not if they want to stay in business very long, anyway. Almost anyone who's been in the business very long has horror story(s) about ticked-off customers demanding a new transmission after a routine fluid change on a high-miles, no-maintenance transmission causes sudden failure within a very short interval. We can argue all day about the exact failure mechanism, but the scenario is well-known. But it is true, as someone pointed out, that if such a failure occurs after a fluid change, you really haven't lost much, since the trans had to be pretty far gone anyway. Transmissions in good condition aren't harmed in any way by changing the oil, with the one caveat Dick pointed out about older cars which originally had the whale-oil based fluid.

The statement that auto trans fluid does not wear out in use is only partially true. The fluid has two distinct functions, lubricating bearings/gears, and transmitting hydraulic forces. The oil does not lose its hydraulic function, but it is subject to shearing forces, and it does undergo chemical degradation, albeit to a far lesser extent than the engine's lubricant, assuming the transmission is not overheated. Thus, over time, its lubricating ability is decreased, hence the recommendation for regular service. And if the trans is overheated, all bets on the quality of the fluid are off.

This page last updated July 21, 2004.  Send us your feedback, and come join the Imperial Mailing List - Online Car Club