Getrag temps and general nonsense

[MMiller]

Last week I finally got to put some miles on my fresh getrag. Took it on a 4 hr drive pulling an empty 18' flatbed car trailer, mostly interstate, and all of it in OD. The good news is, I made it to my destination and home. I'm getting more used to the new clutch and having to put it on the floor for a nice shift. The transmission/clutch sound the same as they used to before I had any problems. I did install a temp gauge on the dash to monitor the transmission temps. I started out on my trip on a 30*F day and traveled down the road mostly 70-72 mph in OD, and a good headwind. It took about 45 minutes to get up to a temp that stabalized at about 190*F. I really don't know what I'm looking for, but I initially thought it would run cooler then that. On the way home I was running between 200-210, but it was a wicked headwind.



My only concern is the fact that its 30* right now, with light load. What's going to happen this summer on 90-100* days pulling 28,000# in OD? I've only got three people to give me any insight. My best friend has a Kenworth with a 13 speed, and loaded heavy it runs around 200*, and he hasn't pulled in the summer with it yet. RPA on hear has a customer with a 6 speed and a temp gauge and it runs 210-230 all the time running hotshot... ... and Chris says his runs 190* and he's running fast coolers. Anybody else have any real world experaince on manual trans temps?



I will have some fast coolers before pulling season, and I will do a transmission service soon, to drain the first oil after the overhaul.....



Michael

 

[Philip]

Michael I used to drive a KW K100 cab over. NTC 350 and a 13 spd it had trans and rear axle temp gages. With a gross of 70k in TX at 100 degrees. The rears and trans normaly ran around 250 degrees temps.



Glad to hear you got everything worked out.

 

[NIsaacs]

I have a mechanical gauge on my six spd and the temps seem to mirror the engine temps for the most part, (heat sink?). At 65 mph on a hot day it runs 190, at freeway speeds, 75 mph it runs 160, (more air flow?). On a cold day it runs 160 at 65 mph. This is with the factory (Mopar) oil, changed every 36,000 miles. Now that my warranty is out, I have switched to 15/40 Rotella, now at 50*F, running 65 mph it only moves about a needle width off the 140 mark. I don't see much difference loaded or empty.



What are you using for oil?





"NICK"

 

[MMiller]

Right now there is Generic 10w30 sythetic engine oil in it. The owners manual calls for a 5w30 engine oil. I'm planning on changing it very soon for inspection/breakin, for some more 10w30 Mobil1 Synthetic. I'm still resisting the 80w90 that some other use, I just think thats plenty thick IMHO. I'm no engineer though. I would like it better if my temps looked more like yours.



Michael

 

[JLEONARD]

Well, FWIW I don't think you will be in trouble using synthetic oil. It can stand a higher temp and still protect just fine. I think you'd be ok at 250 F.

Any way to make some kind of sheet metal thingy to direct some air to the transmission?

 

[Grey Wolf]

I don't have a temp gauge on my trans but I do have the fast cooler and it seems to keep things in order pulling our 28' TT



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[bgilbert]

My getrag seen similar temps running around empty, highway cruise, summertime, Mobil 5w30 5 quarts, would take a good hour or more to reach those temps. A Mack I drove with a 10 speed, loaded, always ran 225* summertime. Looks like the Fast Coolers will be needed for pulling season. Then might even need to try a different lube.

 

[Niki]

I don't think you'd have a problem running a heavier synthetic lube, especially since you work the truck. Synthetic still pours easier at low temps too, so you'd probably be fine in colder months. I had 10w40 in mine this winter and was fine, and have heard of people using 15w40oil, 80w90 and even 85w140 gearlubes on here.

 

[PToombs]

I run 15w-40 in mine, but it hardly ever moves in the winter. I was driving it last fall when it was down in the 20's.

I would never put gear oil in there, too heavy. The local truck repair shop swears by 50wt synthetic in the mid size trucks, f-700 fords, etc.

 

[NIsaacs]

I have 296,000 miles on my '91' D-250 w/Getrag and have used the 15/40 its entire life running the same oil change intervals as the '01'. I do not have a temp gauge, however I think it being a smaller transmission than the 6 spd it probably runs hotter. I have always kinda felt like the lighter weight oils in the newer vehicles for fuel savings was not in the trannys best interest.



For umpteen years, Clark recommended 50 wt in all their trannys. I think it was a good middle ground between the light weight oils and 80/90 wt.





"NICK"