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Old August 23rd, 2015, 09:21 PM
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Matthias Moran
1963 109
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Location: San Francisco, CA
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Auto Transmission Cooling

Can someone clear up my confusion wrt transmission cooling in a 97 D90.
According to the parts manual (I've attached the relevant page) there are three transmission cooler lines:

ESR4219 Pipe assy trans to o/c
ESR3695 Pipe assy o/c to o/c
ESR4218 Pipe assy o/c to trans

According to everything else that I've read, the 97 NAS D90 only had one transmission fluid cooler (unlike some other rovers at the time which had a second cooler inside the main radiator.)

o/c presumably means "oil cooler" so where is the second line going from/to ?

Are there really three lines ? and is there something else that takes the place of the second (in radiator) cooler ? Or are there only two lines in which case the part numbers above are presumably incorrect.

To be honest, it's a bit of an academic question because although I'm working on an auto conversion for my NAS 110, I believe that the stock D90 transmission cooler is too small for my purposes anyway. I was planning to add an additional cooler so will not be able to use most of the standard pipe assemblies. I'd like to keep it close to stock if possible however.
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File Type: pdf Transmission Cooling.pdf (159.4 KB, 36 views)

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Old August 23rd, 2015, 09:27 PM
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On my auto build, I used a plain jane engine cooler only radiator from the 3.5 which is tons cheaper than any others and a common tranny cooler ? Hayden for the transmission.

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Old August 23rd, 2015, 09:57 PM
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I never really understood the diagram and part numbers. I used cooler lines ESR4218 and ESR4219 and cooler FTC5360 on my 1994 when I did the auto swap. There wasn't a need for a third line.
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Old August 23rd, 2015, 10:30 PM
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Matthias Moran
1963 109
Join Date: Jul 2008
Location: San Francisco, CA
Posts: 92
A quick search on ESR3695 suggests that it is used on Disco's and Range Rovers but probably not Defenders.

So I guess that the manual is just wrong.

I had thought about doing a single large aftermarket cooler but ultimately, the problem is lack of space and not wanting to block too much airflow to the radiator and a/c condenser. The stock trans cooler sits nicely along the bottom of the radiator and I was going to add another at the side. (I sometimes use the 110 to trailer my 109 over mountain ranges etc so extra cooling seems like a good idea.)
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Old August 24th, 2015, 12:38 AM
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1999 D2, 1985 D90 truggy & 1951 S1
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If your interested I have the cooler & lines from my 3.9 auto. The cooler is a Mocol & the hoses are Goodridge with 1/2" BSP fittings. I had the cooler mounted above the front x-member for good air flow. PM if you want pic's etc
D100 5.3 LS powered truggy under construction....
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Old August 24th, 2015, 11:43 AM
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Viton Johnnson
Smart 4x4
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I'd definitely use a different cooler than the stock '97 cooler because of it's location. The factory location does not allow any air to be drawn over it by the engine fan so when you're crawling around it's effectiveness is about nill.
A larger cooler mounted in front of the coolant radiator would be much more effective.
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Old August 24th, 2015, 12:39 PM
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Doug Crowther
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You need 3 and 5. I have done several of these and have gotten the correct cooler and lines from Zack @ RN.
The way the lines are pictured is whats confusing as they are showing side views as opposed to how they actually orient to the cooler. Make sure you get the cooler mount brackets as well.

Good judgement comes from experience,experience comes from bad judgement.

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