I have a '63 3.8L MK2 Saloon equipped with a Borg Warner DG250
Automatic Transmission. I was wondering if anyone has ever
installed a ATF cooler to this transmission/car combination. I
just returned from a family vacation this afternoon in the MK2 and
experienced very… slow up-shifting from intermediate to direct
following an extended run on the expressway (Approximately 150
miles). The up-shifting between intermediate and direct returned
to normal after I had run on surface streets for approximately 10-
15 minutes. I thought that perhaps the Automatic Transmission
Fluid became too hot during the highway run thus reducing my
upshifting performance. I’m currently running Mercon III ATF and
changed it at the beginning of the season. Any thoughts or
comments would be appreciated.
In reply to a message from xkemk2man sent Wed 13 Jul 2005:
Hey Brian,
I’m no expert having just begun working on the DG. Having said
that, I wonder initially if you’re using the right fluid. I’m led
to understand that Mercon is slippier than type FA which I believe
we should use. Hopefully an expert can clarify.
Second point, I’d love to hear where we could tap from the DG to a
cooler as I’ve incorporated a trans cooling loop into my new
radiator. I hope someone offers a solution.
Final observation. I thought these trans went into a lockup mode
for cruising which I would think wouldreduce temps rather than
raise them.
Sorry 've offered more questions than answers, hopefully we can
expand the discussion.
Steve–
The original message included these comments:
I have a '63 3.8L MK2 Saloon equipped with a Borg Warner DG250
Automatic Transmission. I was wondering if anyone has ever
installed a ATF cooler to this transmission/car combination. I
just returned from a family vacation this afternoon in the MK2 and
experienced very… slow up-shifting from intermediate to direct
following an extended run on the expressway (Approximately 150
miles). The up-shifting between intermediate and direct returned
to normal after I had run on surface streets for approximately 10-
15 minutes. I thought that perhaps the Automatic Transmission
Fluid became too hot during the highway run thus reducing my
upshifting performance. I’m currently running Mercon III ATF and
In reply to a message from Steve in Las Vegas sent Wed 13 Jul 2005:
hi it could be the heat those trannys did not last long maybe for
that reason but you could braze a 3/8 fitting in the front bottom
of the pan and an other on the back of it. then you just run 2
steel lines up to the radiator, and put a fuel pump in line some
where. turn it on after a 15 minutes run. also you could braze a
fitting for a temp sensor in the oil pan as well. so you could
check on temp. and the dg 250 used F type fluid pajtas–
jaguarjoe 54 XK 120 rdstr 1961 MKIX 94 XJ6
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In reply to a message from xkemk2man sent Wed 13 Jul 2005:
Graham & Peter @ G.Whitehouse Autos have developed a cooler for the
DG250 and users, including a slightly mad dutch classic sporting
enthusiast confirm a termendous improvement in performance and life
of seals and fluid. I have no affiliation other than as a very
satisfied customer; Graham rebuilt the DG box in my car 5 years and
30,000 miles ago and it has not spilt a drop since, and remains
quiet and strong.
G.Whitehouse Autos Ltd Brooklands House Nimmings Road Halesowen
West Midlands B62 9JE. Tel: +44 121 559 9800 www.gwautos.com–
John & Tigger (3.4 Mk 2 Auto 1966)
Tamworth, United Kingdom
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In reply to a message from pajtas sent Wed 13 Jul 2005:
Having done a little research on the DG250 Which was the only auto
transmission that Studebaker used in the time period (50-55), Borg
Warner said that the original fluid was Type A and Dexron is the
successor to Type A. The Type F will work also but gives firmer
shifts than Dexron.–
The original message included these comments:
check on temp. and the dg 250 used F type fluid pajtas
I had thought the unit could benefit but I’m concerned the fuel pump diaphragm is not made for the temps the tranny fluid develops in comparison with gasoline.
I had my DG250 serviced by a transmission specialist in Sydney. He noted that it was as “clean as a whistle” internally - now 64,000 miles. I quizzed him about F type that should be run in these - superseding A type. He insisted that Dexron III was the compatible replacement. Per above the do lock up by solenoid action when moving to top gear. One test might involve forcing the shift using the intermediate hold - if not done already. I tend to think earlier comment us right - being locked up like top gear in a manual should reduce heat in the fluid? Paul
Going to try to get this written without the damn pop-up telling me there was a previous thread!
What is the purpose of that message if the thread never answered my question. It blocked me as I could not find a way to remove it?
The DG-250 appears in several models of Jaguars and in my MKVII and MKIX.
Never saw an auto box that couldn’t be helped by a cooler and considering theMKVII is close to 3 tons, it applies here.
No problem putting one in as fabricating a send and return circuit is a walk in the park.
What I want to know is how to circulate the fluid. A fuel pump was recommended, but I question the pump’s ability to handle the temperature of the fluid when it’s at operating temperature. Fuel pump diaphragms are usually made of rubber and do not ever see that type of temp from a gasoline tank, so I really question how long it would last.
Any suggestions for moving this fluid or have you actually used used a pump and does it still work?
I would start by researching if the DG250 was ever offered by any other maker with a cooler, perhaps Volvo. Then find out if there is a pair of plugged holes, or possibly undrilled bosses, already on the transmission.
Failing that, some of the PAS conversions use electric pumps which can handle ATF, as do some of the more modern transmissions. The Alfa Selespeed pump is about the size of a pair of large coffee mugs, half of that is an accumulator. The PAS pumps might be too high a pressure, the Selespeed has a pressure sensor built into the accumulator, so you’d need to deal with control.
Failing that, try Pegasus racing or such. The German equivalent of Pegasus sells electric pumps suitable for oil, here’s one:
I was surprised to see my original post from 12 years ago re-surface. I’m happy to chime-in and close the loop on the slow shifting issue that I was experiencing all those years ago.
I ended up removing the engine and transmission and having the DG250 box and torque converter rebuilt by G. Whitehouse Autos, Ltd. in the West Midlands, England. They did a wonderful job. The transmission shifts at the prescribed shift points per the factory service manual regardless of operating temperature or length of run.
It took a bit of fiddling to adjust the throttle kick-down linkage and governor rod properly. It’s a very sensitive arrangement. Very small adjustments resulted in a dramatic changes in the shift point rpm. after some trial and error, I was eventually able to calibrate the transmission shift point with the appropriate engine rpm and load.
WRT Transmission Fluid, I am running Morris Liquimatic Dexron DII Transmission Fluid. (This is the fluid that was recommended by G Whitehouse Autos).
When properly sorted out, the DG250 box is quite a nice transmission in operation…Not bad for a vintage hydro-mechanical design. It’s amazing what Borg Warner was able to accomplish given the state of automatic transmission development in the 1950’s. Ford Motor Company is a client of ours and we do a lot of work for Ford Automatic Transmission Operations (ATO). The level of hardware and control complexity in today’s transmissions is mind-boggling. 9-speed FWD, 10-speed RWD configurations, efficiency targets, drivability targets, durability targets, NVH targets…Good Lord…It’s astonishing what today’s engineers are delivering.
Check with people in the RV industry. I believe, but am not sure, that pumps are made to circulate auto transmission fluid in vehicles that are flat towed behind motor homes.
I have been driving automatic MK saloons since 1967 when I bought my first car, a two speed automatic MK 7. I also have a 59 MK 9 and a 61 MK 9’s that I drive as much as possible. For years I used Dexron ATF in my MK 7, recommended by a transmission shop that installed a torque converter seal when I had the transmission out during an engine rebuild in 1973. I never had any issue with the fluid, other than keeping it in the transmission.
I started running my 61 MK 9 in 1997 and replaced the original ATF with Dexron and ran it for several years. Based upon research and recommendations of many “experts”, I changed it to Type F, which I now run in all three cars. The shifting is firmer, more positive.
On hot days, after the engine has really warmed up, the shifting into third is rougher. It has never been a problem however Would the addition of an oil cooler help? I suggest it would depend upon how much heat transfer it is capable of. If the oil is running at, say, 175 deg. F, would a 10 degree drop in temp make any difference, or is 20 or 30 degrees required, or more? Some engineering needs to be done here to justify the effort of fitting a pump and cooler.
Going to try to get this written without the damn pop-up telling me there was a previous thread!
What is the purpose of that message if the thread never answered my question. It blocked me as I could not find a way to remove it?
The DG-250 appears in several models of Jaguars and in my MKVII and MKIX.
Never saw an auto box that couldn’t be helped by a cooler and considering theMKVII is close to 3 tons, it applies here.
No problem putting one in as fabricating a send and return circuit is a walk in the park.
What I want to know is how to circulate the fluid. A fuel pump was recommended, but I question the pump’s ability to handle the temperature of the fluid when it’s at operating temperature. Fuel pump diaphragms are usually made of rubber and do not ever see that type of temp from a gasoline tank, so I really question how long it would last.
Any suggestions for moving this fluid or have you actually used used a pump and does it still work?