Transmission temperature?

[kassim503]

How hot would the normal operating temp for the L4N71B be around? What sounds like a healthy temperature? 180? 210? My tranmission hits 180 cruising and 210-220 heavy traffic conditions and im contemplating installing a trans cooler to make the transmission last longer.

[asavage]

Those numbers look normal to me. My "ouch" point is 250°F, where conventional ATF performance really begins to drop off. Below that temp, I don't get too concerned. The OEM cooler dumps the ATF heat to the coolant, and the coolant is between 190° and 200° most of the time, so getting the ATF below 200° is nearly impossible unless you use a secondary ATF cooler, plumbed after the OEM in-tank cooler.

If you're not towing, I wouldn't bother. When the torque converter locks up, the amount of heat generated by the geartrain is nil, compared to when the converter is open. Towing with an open converter is where you get into trouble.

220° for the top temp is fine. Even better if you are running a synthetic ATF.

On the Aero (with the early, grenade-style A4LD, otherwise known as "Automatic Four-speed, Light Duty"), that comes from the Ford with an in-tank cooler -- mine has the "towing package" that includes a factory external tube-n-fin cooler in series -- I added another cooler in series with that -- for a total of three ATF coolers -- when I had the trans rebuilt in 1999. Filled it with AMSOil ATF, had the pan modified for a total-drain style drain plug, and I drain 2.5 qts out of the sump every third oil change and refill with the same synthetic ATF. Small inline filter on the cooler line, with a magnet inside, that I replace about every January. Knock on wood, the ATF color is still good 76k miles later, and you know how hard I run the thing. My current trans guy just shakes his head when he see the pics of me towing cars & trucks with this trans.

Once up to speed, I work hard to keep the torque converter locked though. If you let the A4LD automatically downshift from OD to direct, it will open the TC, which is why Ford advises not towing in OD. However, if you manually downshift to direct, the valving keeps the TC locked (unless you floor it in direct), so I spend a lot of time manually shifting between OD and D if I think I can't pull a grade in OD. I don't wait for the trans to downshift itself. I don't know how this compares to the L4N71B shift strategy.

Where are you measuring the ATF temp? Leaving the trans (leaving the torque converter, really) or leaving the OEM cooler (ie the sump temp)?

[kassim503]

Truthfully im not all that sure what im measuring it from, I found a threaded plug in the drivers side of the transmission and I just threaded the sender into there. Pretty sure its out of the converter fluid though.

I looked at some graph/table/chart and it says running at 175F instead of 195F would double trans life, is this bs? I dont think 190 is so bad, and if i run a cooler I might never get any heat in the winter.

[asavage]

There are a LOT of places on the web that are saying, "every 10 (or 20) degree rise in temp halves the life of the ATF" or words to that effect, and some are extending the life of the oil to mean the life of the transmission. I don't buy it. Research -- ie research that actually measures the "life" of an oil using established metrics -- is clear that conventional oil's "life" is pretty severely reduced above 250°, but that doesn't account for variations in various additive blends and base stocks.

Non-synthetic ATF isn't all that great when its real cold, either, but at least it doesn't deteriorate like it does when subjected to temps above 250°.

I suppose that the life of the ATF may be extended by moving the average ATF temp down under 200°, but you're still going to have to change it to remove the crap from the normal or abnormal wear of the transmission components. Put another way, if you can extend the useful life of the oil but there's crap suspended in it, what's the point? As long as the clutches lock up at a reasonable rate during shifting, and the seals don't get fried from excessive temperature, then the temperature is "OK". The life of the oil is really quite good already, with the OEM setup. If you change it or flush the trans or whatever, every so often, even as little as every 60k or 100k, the transmissions seem to hold up just fine. Other than Wayne, I haven't heard of any automatic transmission failures at all in the Gen1s.

This is just my opinion, of course. I don't see a big downside to adding more cooling capacity, and you can purchase a bypass thermostat for the extra cooler pretty cheaply, that allows the trans to come up to temp normally.
============================================

[Sidebar: the GM HydraMatic -- not the later "TurboHydraMatic" that we're all familiar with -- was used in the higher-end GM vehicles from about 1952 to 1963, notably ALL Cadillacs. This is a four-speed automatic. You read that right: a four speed automatic in 1952. It is not an overdrive transmission, though. Fourth gear is direct, like third is in most ATs today. Cadillac (and the other marques that used it, such as Oldsmobile, Packard, and Rolls Royce) had a high-geared differential and first gear was very deep, so the effect was like that of overdrive, but without the complication and geartrain losses associated with an overdrive unit. The concept was a good one, and you might be astounded at the fuel economy of those early Cadillacs. My '62 Sedan DeVille (four door, 390ci) would return an honest 21.5 MPG at 70 MPH. I am not kidding. My '59 Eldorado Seville (a fairly rare combination model) that came from Cadillac with a lower rear end, factory dual exhaust and three dueces -- yes, Cadillac put three two barrel carbs on their top-of-the-line Eldorado back then -- got about 17 MPG with me driving it, and I was a leadfoot in those days. These are not light cars, but with a smallish (by Cadillac stds to follow) engine and tall final drive gearing, if you got it up to speed and kept it there you could get very good mileage. Not Rambler economy -- they had a 199ci Six and overdrive -- but for that kind of car, very very good.

Back to the old HydraMatic: it has ATF temperature compensation. When the ATF is cold, a bimetal spring opens a port and reduces shift pressure to soften the cold shifts, because ATFs of the day could not maintain anything like constant viscosity over a 200° range.

Cadillac was the last to hang on to the 4-spd "dual coupling" HydraMatic, and they used it until 1963, with the 390ci engine. In 1964, Cadillac and Buick got the first of the new TurboHydraMatic transmissions, the very first TH400, one with no 1st gear "L" on the PRNDL: they were three-spd transmissions but you could not pull it into 1st gear manually (that first year), because it has a different valve body from the later years. Ask me how I know . This is not to be confused with the Super Turbine 300 (a two-spd AT that was like a PowerGlide in function but built kinda out of TH400 parts) or the TH350, which didn't come along until (IIRC) 1967.

Apparently late '63 models of Cadillac got the new TH400. I know this only in a round-about manner:

The 365 and later 390 use flange-mount Delco starters, with horizontal mounting bolts to the bellhousing. The later '64 429 engine (a one-year block, BTW, though the '65 got the same displacement but a different block -- again, ask me how I know!) uses the more common GM practice of a pad-mounting, with the starter's mounting bolts vertical to the block.

Anecdotally, the HydraMatic plant burned down sometime in '63 -- I have not even tried to Google this for accuracy. The new TH400 was supposed to be used in the '64 lineup but got pressed into 1963 service. There was no way to bolt up the starter.

After all these years and all the Cads I've owned, I own a single Cadillac part today: the cast-iron adapter that -- I think -- allows one to bolt a TH400 behind a 390 engine. It is broken and missing an important section, but I think that's what it is. If someone can correct me or fill in the details of the circumstances surrounding the Great 1963/64 Cadillac Transmission Controversy, please email me.

The HydraMatic was plagued with problems. It uses a fluid clutch rather than a torque converter, which would give harsh shifts unless compensated by slow clutches engagements -- which wore out the clutches. Essentially the same transmission was used in Chev & GMC trucks of the 50s, and they were calibrated with much higher shift pressures and the transmissions held up much better.

There is a drum that cracks and leaks fluid and prevents second and fourth gear engagement. That's the way I bought my '59: 1st and 3rd gears only. This used to be a common problem back in the day.

In summer/fall of 1980, I ran an ad in the Seattle Times, looking to buy a Cadillac of the 1959-63 variety. I received a LOT of replies. This was prior to the release of the movie "GhostBusters", gas was expensive (for the time) and nobody wanted these old boats except me. A friend and I looked at about 29 Cadillacs in the next three months. Most of them were sitting in the weeds or backyards or alleys with bad transmissions. I ended up buying a '64 Convertible, fully optioned with white leather bucket seats and the first year with Climate Control and transistors instead of tubes for the various electronic devices -- of which there were several, what with Climate Control and Autronic Eye and all. The '59 Eldo/Seville came a year later.

The HydraMatic was one of a bunch of transmissions that had the shift pattern with Reverse on the right, after Low: PNDLR. Made for easy burnouts: put selector in Reverse, floor loud pedal, watch smokeshow. When the rear tires hooked up, nudge selector up one click to Low. Continue smokeshow.

Repeat, lather, rinse.

I kind of "repaved" a concrete drive of a house I was renting in Mesa using this technique. I worked nights at a Union 76 where I could get all the used tires that I wanted for $5 a pop, and mount them myself. I put three rear ends in that '59 before I sold it.

The HydraMatic for 1960 added a Reverse blocker servo, to prevent shifting from Reverse to Low (or was it Low to Reverse) if you were "moving" above 5 MPH, to prevent drivetrain damage (such as I inflicted on mine). The Hydramatic continued to utilize twin pumps, one driven by the driveshaft, until the end, so you could always push-start a Cadillac -- until 1964. Powerglides retained this feature through 1967.]

[kassim503]

....The HydraMatic was one of a bunch of transmissions that had the shift pattern with Reverse on the right, after Low: PNDLR. Made for easy burnouts: put selector in Reverse, floor loud pedal, watch smokeshow. When the rear tires hooked up, nudge selector up one click to Low. Continue smokeshow.

Repeat, lather, rinse.

I kind of "repaved" a concrete drive of a house I was renting in Mesa using this technique. I worked nights at a Union 76 where I could get all the used tires that I wanted for $5 a pop, and mount them myself. I put three rear ends in that '59 before I sold it.....

ooooh yea

Once, I tore a layer of sealcoating on my driveway from spinning the maxis old dry rotted tires that I was swapping out.

I keep wondering this, if you do a burnout on your driveway, and a cop sees you, does that mean sombodys getting a ticket? I spun the tires a little right when a unit drove by and he saw me and everything and I thought I might get busted for something but he just drove on. Was he being nice?? Does that sound like disturbing the peace?

But back to the oil cooler, I decided on installing one, but im going to do it before the factory cooler so it can heat up the fluid in the winter, and I have a cooler just laying aorund so I should put it in use and slap it in. Not a major cooler, just a little one that I think is off a chevy pickup, if it does anything thats nice and I can see the cool looking cooler bolted up on top of the radiators. I really dont care about fluid life, ive been changing it once a year since I got the car, but before i got it it had 168k miles on it with the factory fluid. When I drained it, it was some funky stuff

[HowlerMonkey]

Grade retard?

[fud2468]

I can recall a mechanic describing to my father around 1941 how a Hydramatic worked, he told him it had planetary gears just like Model T Fords had had since 1909.
I clearly remember the whine as they drove by and you could hear the RPM's drop suddenly as they upshifted.
For a while, I think 1949-51, Lincolns had Hydramatics. Ford did not yet have its own automatics and they bought them from GM.
IIRC, the 1953 tranny plant fire led to some Cads and Olds having to be equipped with Buick Dynaflows.
Ray Mac.

[philip]

SNIP
The HydraMatic for 1960 added a Reverse blocker servo, to prevent shifting from Reverse to Low (or was it Low to Reverse) if you were "moving" above 5 MPH, to prevent drivetrain damage (such as I inflicted on mine). SNIP

GREAT stroll down memory lane!

The intention was to prevent shifting from Low to Reverse.

Both Twin and Single turbine Hydramatic 4 speeds had a reverse blocker valve starting in 1956. The Hydramatic 3 speed also had a reverse blocker.

[davehoos]

ATF temp.

warming the transmission is up to a "normal" is more of an issue.synthetic oil can help with cold shift issues.
R31 has an overheat sencor in the oil pan i believe its around 195f.it basically cancels overdrive and lock up.when cold the trans wont select overdrive.cant remember if this is controled by the water temp sencor.this is also assist emision outputs.

oil cooler is in the bottom of the radiator.this temp should be well bellow engine water temp.if a cooler is used it should be placed in the circuit in the hot/outlet side before the radiator.simple rule of thumb is that 80c is good.more is not bad.

with local australian cars cooler have been getting bigger some have them in both tanks of the radiator like nissan patrol did,but with a lot less water..im told there is problems with these bursting.new release falcon has gone for a membrane heat exchanger bolted to the engine sump and uses thermostat controlled water that is at a lower temp compared to the engine.

holden used the early 4 speed auto on 1960-1965 range with grey 6 cyl 132 CI.the low first was to allow for the early tourque convertor design.
these cars sold in hawaii guam etc to cover costs of the imported trans.
this was replaced with the powerglide half manufactured here,and the trimatic[different name in USA].trimatic here used powerglide parts.we didnt get the 4 speed trimatic,suzuki 4x4 used the old pre 70,s cable kick down casing.

Australia Design Rule [ADR] requires a standard shift pattern,this kicked in here between 68-75.reqires PRND in that order.fitting a

[asavage]

R31 has an overheat sencor in the oil pan i believe its around 195f.it basically cancels overdrive and lock up.when cold the trans wont select overdrive.cant remember if this is controled by the water temp sencor.

The A4LD uses this strategy as well. No OD until some minimum coolant temperature is achieved.

if a cooler is used it should be placed in the circuit in the hot/outlet side before the radiator.

While opinions vary on this topic, I come down on the other side: install auxilliary cooler in series with OEM cooler after the OEM cooler, which leaves the possibility of cooling the ATF below engine coolant temperature. Hayden also advises this.

Australia Design Rule [ADR] requires a standard shift pattern,this kicked in here between 68-75.reqires PRND in that order.

In the States, regularisation of the transmission shift pattern occured in 1964 or '65. Shifter location on motorcycles occured in 1972 or '73.

Grade retard?

Nope, that was the TurboGlide -- I think that was a Chevy-only trans. I am told that that transmission had a lot of trouble, and replacement with PowerGlides was common.

I can recall a mechanic describing to my father around 1941 how a Hydramatic worked, he told him it had planetary gears just like Model T Fords had had since 1909.

True, as far as it goes. One of a handful of things I'd like to do someday is to drive a Model T. Four pedals: Reverse, High/Low, Brake, Accelerator. A lever on the left side will hold the High/Low pedal halfway down, for Neutral! I bet not a lot of people reading this have any inkling of how weird it was to drive a Model T, compared to more modern cars.

I just haven't found a Model T owner willing to let me take a spin yet. I've done quite a bit of work on Model As, but they're a lot more like a modern car than the T is.

For a while, I think 1949-51, Lincolns had Hydramatics. Ford did not yet have its own automatics and they bought them from GM.
IIRC, the 1953 tranny plant fire led to some Cads and Olds having to be equipped with Buick Dynaflows.

I'd forgotten about the Lincoln, but now that you mentioned it: yeah. I'd heard that the plant burned in both '53 & '63, but can't credit the veracity. I'd thought it was the other way around, that HydraMatics got put into other cars instead of the cast-iron PG or Dynaflow or whatever. [shrug]

[fud2468]

On the Model T there were 3 foot pedals, low, reverse and brake. Pushing these caused bands to contract on drums in the tranny. When the brake band wore out some people used the reverse pedal to stop until that wore out, too, then replaced all 3 bands at once
As you say, Al, the E-brake handle was to the left. To "go through the gear" you stepped on the low pedal to get going, let the brake handle all the way forward and after a few feet let the low pedal out and it went into direct drive. 2 speeds total. Hand cranking in cold weather was an adventure, even in neutral there was tranny drag enough to run a person over if it started, tranny shared oil with engine .
I had several as a kid on the farm, including a 1927, last year of production, but don't recall a foot pedal for accelerator. That one did have the combo choke and mixture control button on a rod going to the carb, like the Model A did. Also by then, gas tank was under the cowl instead of under the seat, meaning it was no longer necessary to back up a hill when fuel was low. Oh, yeah, gas gage was a stick you stuck down into tank when you decided to check. No oil pump, fuel pump or water pump, no oil dipstick, but it was ahead of its time(?) with one ignition coil per cylinder.
Could go on & on, about aux trannies, etc. but won't right now....Ray Mac

[philip]

if a cooler is used it should be placed in the circuit in the hot/outlet side before the radiator.

While opinions vary on this topic, I come down on the other side: install auxilliary cooler in series with OEM cooler after the OEM cooler, which leaves the possibility of cooling the ATF below engine coolant temperature. Hayden also advises this.

Automatic Transmission Fluid Overheating:
New Jersey Forest Fire Service’s Solution to High Temperature Problems in Ford F-350 and F-450
Roscommon Equipment Center, National Association of State Foresters
in Cooperation with Michigan’s Forest Fire Experiment Station

Automatic Transmission Fluid Temperature
Automatic transmission fluid (ATF) has a life of about
100,000 miles at 175F. At high temperatures, it oxidizes,
turns from red to brown and exhibits a burnt smell. In
addition to reducing the oil’s lubricating quality, high
temperature produces a varnish on internal parts
interfering with the operation of the transmission. Above
250oF., rubber seals harden, leading to pressure loss and
leaks. Also, the transmission can slip. In the worst cases,
clutches fail and costly repairs result. SNIP

ATF manufacturers suggest that for every 200F. increase
in operating temperature above 175F., the life of the fluid
is cut in half. Hence at 195F., oil life will be about 50,000
miles. Above 240F., it becomes nil. Without adequate
cooling, the heavy duty use of wildland fire engines will
likely push the ATF operating temperature very high.

[asavage]

Ray, I appreciate the historical perspective! I am too young to have had easy access to T hardware in runnable condition, more's the pity. I have wanted to drive one for a number of years. I've put clutches in two As (which as I'm sure you know is a "remove the rear end" process) and have had enough miles driving them, but I guess I'm just not hanging around with the right folks, as I haven't been able to get a ride in a T yet.

On the Model T there were 3 foot pedals, low, reverse and brake. Pushing these caused bands to contract on drums in the tranny. When the brake band wore out some people used the reverse pedal to stop until that wore out, too, then replaced all 3 bands at once.

Yes, that's what I've heard too. Just push on everything to stop!

As you say, Al, the E-brake handle was to the left.

Not quite the way I recall. The lever on the left that I remember, will "set" the Hi/Low pedal to halfway down, giving Neutral. Perhaps it also works as a park brake? It's been a while since I've been able to find my T manuals.

To "go through the gear" you stepped on the low pedal to get going, let the brake handle all the way forward and after a few feet let the low pedal out and it went into direct drive. 2 speeds total.

I've heard that it's nearly impossible to "upshift" (let the pedal up through neutral and up to high) smoothly, it wasn't designed with smooth in mind!

Hand cranking in cold weather was an adventure, even in neutral there was tranny drag enough to run a person over if it started, tranny shared oil with engine .

Oh? I definitely didn't know the shared lube situation (but I'll throw in that the Austin Mini does that too, even the (vintage) automatic Mini in the 60s -- which, BTW, is also a four-speed auto! Yes, engine oil in the automatic transmission -- this, on an engine that has no real oil filtration, just a screen (ala Simca and old VWs)).

Still . . . with proper band adjustment, I don't know why there'd be drag. Unlike modern automatics (which use a "forward clutch" that is multiplate and runs in oil much of the time), the T's bands were dry -- weren't they?

I had several as a kid on the farm, including a 1927, last year of production, but don't recall a foot pedal for accelerator.

The way I recall it, the foot feed was either an option or one of the hundreds of aftermarket add-ons, I don't recall which. The hand-throttle was the primary way to control the throttle.

I also didn't know that the T moved the fuel tank up front like the A.

The last time I was near a T was in a large auto museum in 2000, a converted Montana state prison that had recently (!) been converted to museum status, and a pretty good job of it. I was driving my original (86k documented miles, one owner) '63 Falcon Deluxe wagon to its new owner in Chicago, taking a leisurely five days to drive 2200 miles in August, a very nice drive BTW. I stopped off at the auto museum on a Tuesday I think, the place was nearly deserted, and I wasted a couple of hours looking at the cars, almost all of them on display are privately owned but "loaned" to the museum. Hundreds of them. Almost all are roped off and "do not touch" signs, except . . . two or three cars in one section, with a sign, "climb in and touch all you want". One of those was a '16 T, er, "Roadster" or whatever the open-top version was called. So I got to sit behind the wheel. It also had the foot-feed, but I'd seen them before.

Weren't the Ts two-wheel braked? I know the As had four wheel brakes, though still all-mechanical -- one of the ones I worked on had the "40 Ford" hydraulic conversion done to it, and I had to revamp (redesign, really) the master cylinder linkage as it would not work at all! The other had the original all-mechanical brakes, and that merely needed the usual maintenance and finicky adjustments, but I could get it to stop straight, quite a feat if you don't have everything just right.

[asavage]

Automatic Transmission Fluid Temperature Automatic transmission fluid (ATF) has a life of about 100,000 miles at 175F. SNIP

ATF manufacturers suggest that for every 200F. increase in operating temperature above 175F., the life of the fluid is cut in half. Hence at 195F., oil life will be about 50,000 miles. Above 240F., it becomes nil. Without adequate cooling, the heavy duty use of wildland fire engines will likely push the ATF operating temperature very high.

While the above may be true for HD and off-road heavy equipment, I am very sceptical about these numbers for on-road use. 100k miles? Yeah, that's pushing it for ATF but for contamination reasons not oil breakdown. That's for decent quality ATF though.

The number I have the most scepticism for is that 175°->195° halving-of-life thing. I have my hot tap water at 180° -- don't lecture me on scalding issues, I live alone and I live dangerously -- and I just can't/won't believe that ATF's life will be cut in half when it's run at 195° rather than 175°. (Hey, I can compare apples to mangoes too!) I think someone is quoting someone else who quoted someone else who overheard that at a cocktail party or something. I would like to see that quote from an ATF manufacturer, rather than a user or maintenance dept. or oil cooler vendor.

I like clean oil. I like synthetic oil. To a degree, I like cooler rather than hotter oil. But 175° ATF is pretty hard to acheive under any non-trivial load and I don't think there is a real benefit. But I'm trying to keep an open mind -- just not so open that my brains fall out.

[philip]

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