Any problems or factory defects with the '94 XE 4X4? Any tranny modifications that help preformance?

[Pathfinder94]

I have a '94 XE 4X4 (my first nissan) that i just changed the (auto)trans in. I do not want to burn up the new one like the previous owner did the old one. Just have a few possibly dumb questions. What is the best tranny cooler to use (i live in Scottsdale, AZ)? Would it be best to run it solo or along with the factory one? Is it best to run a transfer case manual lock switch (that i have heard little about) or not, When is the best time to use or not use the OD OFF switch (i here some conflicting info on how it relates to the torque converter), just trying to find out what is best for the tranny. I do a fare amount of off roading, don't do much towing (dirt bikes on a small trailer is the extent of it) but a lot of freeway use. I also take the occasional trip up north where you will ascend 2500 feet in a short amount of time. Everything is stock except wheels, tires and torsion bar adjustments. Any input would be greatly appreciated.

[Kyle94]

I used a 28GVWR Hayden external tube and fin style cooler. cost about 50$ and got it at my local oreilly auto parts. easy install and works perfect. as far as the built in cooler.. i dont trust it. so i left it out as there isnt really any reason you would need it anymore. Thats just my opinion.

As far as the OD being on and off. i try to leave mine off up to 35mph and then after that turn it on. but i do a lot of crusing at 35mph so i have mine on bascially all the time. haha. i was told its best to leave it off up till 35.

[Kyle94]

Oh, and getting a temp reader would be cool too, to monitor the temperature of the tranny. i have yet to do that yet. but i found the one i want. these transmissions do NOT like to be hot... bad things happen!

[Slartibartfast]

I leave mine off up to 45, and even then I only click it on once I'm up to speed. My (likely flawed) understanding is that OD/off locks up the converter and disables fourth gear, which keeps the heat down and the engine speed up so you don't have to floor it to gain speed. OD's nice when you're cruising on flat terrain at a steady speed and you don't need to be pushing 3k rpm, but the rest of the time it makes the truck sluggish and makes a lot of heat the transmission doesn't need in the process. A new tranny cooler could eliminate the heat concern, but the truck would likely still drive like a heifer.

[Precise1]

Agreed with the 'leave OD off around town or when wheeling, although I have heard it should be shut off if you are driving in hilly country.

 

The tranny cooler issue has been deeply discussed, as you can imagine. So I'll give you a brief break down and then give you some homework.

The tranny developes particulates that can cause the stock cooler to clog, cutting off flow and overheating/frying the tranny. You want an external aftermarket cooler, preferably a plate type as they are the most efficient for the room you have to mount it. Most people completely bypass the stock cooler, but if you install an inline filter this shouldn't be an issue and you can run a set up that goes from tranny to filter to stock cooler to aftermarket cooler back to tranny. I believe that this set up is the best as it should keep the temperature fairly constant and reduce temp spikes also. This leads us to installing a tranny temp gauge as well. This is what I did...

http://www.nissanpat...__+tranny +temp

I bought my Pathy with a recently rebuilt tranny also and it's the first automagic I have owned for ower 20 years so I am suitably paranoid myself. D:

 

Here is some light reading,

http://www.nissanpat...ch&fromsearch=1

 

And I'm going to move this to the Garage section to keep things organized.

 

B

 

Oh, there is a 'shift kit' that used to be available but I don't know how effective it was, very few people bother with it...

Edited November 2, 2012 by Precise1

[Towncivilian]

Absolutely get an auxiliary transmission cooler. B&M 70278 is 19k GVW and is a stacked-plate type design. It is thin enough to not have any clearance issues on WD21s. I'd also suggest installing a Magnefine in-line transmission filter. Do a complete fluid exchange via the transmission cooler line as well; use any fluid that claims to meet Dexron III specification.

[Alkorahil]

Absolutely get an auxiliary transmission cooler. B&M 70278 is 19k GVW and is a stacked-plate type design. It is thin enough to not have any clearance issues on WD21s. I'd also suggest installing a Magnefine in-line transmission filter. Do a complete fluid exchange via the transmission cooler line as well; use any fluid that claims to meet Dexron III specification.

 

Hayden is good, but I prefer the stacked plate B&M with steel protection around it as well. I have used B&M both times and had no problems at all.

[ahardb0dy]

Absolutely get an auxiliary transmission cooler. B&M 70278 is 19k GVW and is a stacked-plate type design. It is thin enough to not have any clearance issues on WD21s. I'd also suggest installing a Magnefine in-line transmission filter. Do a complete fluid exchange via the transmission cooler line as well; use any fluid that claims to meet Dexron III specification.

 

I don't think the part number you listed is a correct part number. Can not find it on the B&M site, also where do you get the 19K GVW from? all I see are the coolers rated in BTU's?

[Pathfinder94]

Thanks everyone for the helpful info.. I will be tackling this project soon.

Also i believe (if i am not mistaken) there is a conversion from BTU's to GVW's ( for ahardb0dy) hope this helps.

[Towncivilian]

Sorry, I meant 70268.

[ahardb0dy]

10-4

[Pathfinder94]

Ok.. Just to clear things up (maybe another dumb question), I understand you turn the OD off around town (under 40mph) and wheeling out in the sticks, but let's say you are on the highway traveling about 65mph (OD on of course) and you are approaching a long straight hill, half way through you can tell your trans is working hard and starting to heat up some (the hump is getting hot) but you are not loosing much speed (still around 55 or 60mph) but still have a mile or so to the top (RPM's are around 3k) Do you wait to see if your speed decreases below 40mph to switch the OD off? or can you switch OD off at that speed to prevent excessive thermal issues to the trans by the OD off locking the torque converter? or will that shoot the RPM's through the roof? What would be the best decision in this situation to not damage the trans? Thanks for all your help.. Sorry if i am beating a dead horse or wearing on anyones nerves. Just want to have the correct function for any situation.

[Slartibartfast]

I drop it out of OD as soon as it feels like it's bogging, partially from impatience, partly because the longer it does that, the more heat it makes and the more it slows down. I drive the same route four days a week, so it's mostly habit at this point. At 65 you should be fine to drop it down. I routinely drive 60+ with the OD off, and it stays at around 3.5k.

 

I've never felt heat coming off my transmission hump, so I dunno what to say there. I've heard that it's common. My commute is pretty short. Taking it out of OD should help keep the trans cooler, though.

[adamzan]

I'm going to disagree with the others here, I leave the OD on all the time, unless I'm towing, or I would like to engine brake on a steep grade (rare). My first wd21 went over 400k, 220 of that was mine. I follow the same practice with my new one. When I drove through the rocky mountains I just slowed down to 55mph and it was content with that.<br />

Edited November 6, 2012 by adamzan

[Trogdor636]

Looks like you edited your post on tapatalk! I learned quickly the mumbo jumbo it creates when you do that.

[Pathfinder94]

Thanks guys...

[Alkorahil]

IIRC the owners manual recommends if you are doing sustained speeds under 45 mph and/or stop and go traffic to keep it off.

[Precise1]

Absolutely get an auxiliary transmission cooler. B&M 70278 is 19k GVW and is a stacked-plate type design. It is thin enough to not have any clearance issues on WD21s. I'd also suggest installing a Magnefine in-line transmission filter. Do a complete fluid exchange via the transmission cooler line as well; use any fluid that claims to meet Dexron III specification.

Thanks everyone for the helpful info.. I will be tackling this project soon.

Also i believe (if i am not mistaken) there is a conversion from BTU's to GVW's ( for ahardb0dy) hope this helps.

 

Just something I ran across about the B&M coolers and BTU to GVW conversion.

B&M #130-70268

 

Automatic Transmission Cooler Only

• 19,000 GVW
  
• 13,000 BTU
  
• 11'' x 7-1/2'' x 3/4''
  

This equals 1.46 BTU per 1lb GVW

 

B&M #130-70255

 

Automatic Transmission Cooler Only

• 16,000 GVW
  
• 9,800 BTU
  
• 11'' x 5-3/4'' x 3/4''
  

This equals 1.63BTU per 1lb GVW

 

B&M #130-70264

 

Automatic Transmission Cooler Only

• 24,000 GVW
  
• 14,400 BTU
  
• 11'' x 6'' x 1-1/2'
  

This equals 1.66 BTU per 1lb GVW

 

Obviously this doesn't add up. BTU (British Thermal Unit) is approximately the amount of energy needed to heat 1 pound (0.454 kg) of water, which is exactly one tenth of a UK gallon or about 0.1198 US gallons, from 39 °F to 40 °F (3.8 °C to 4.4 °C). I don't believe there is any direct conversion factor to GVW, but as a roughtimate you can use a factor of 1.6 to get close. Best case scenario is to forget the BTU and make decisions solely based on the GVW rating of the cooler. Again, the commonly accepted minimum requirement for a Pathfinder is 18,000 GVW rating. Hope this helps...

 

B