Engine/Transmission (1998.5 - 2002) 6 sp temp at speed

[monkfarm]

I was running out west (75 speed limit) with my cruise set at 80, and the tran temp started to creep up: 220, 230, maybe even 235 or 240. This seemed too high. Anyone with opinions on this subject??:-{}

 

[redram]

What is a 6 Speed with a 6X6?



Yes, running unloaded at that speed in low ambient temperatures should not approadch 240 F. Did you check the oil level. ?

Anything that you could add that you have performed to the transmission in the last three years would help?

Running loaded (pulling +10,000 lbs) and running 70 + and pulling grades during summer - yeah 200+ is reasonable. But tooling down the highway in the middle of winter, this seems high.



Bearings and seal life will be drastically reduced if this was the norm.

 

[monkfarm]

6 wheels =4 wheel drive. transmission is stock 6 speed. I just had the 6 speed put in (replacing the 5 speed) at blumenthals at ok city, a couple of months ago. I asked them at that time whether they had filled transmission, and they assured me, yes they had. I had called up on the way out of there (when cruise set at 80) temp at transmission went up to 220) if that was normal. Whoever I talked to (Keith in Sales) assured me it was. It seemed a high temp to me. I will check out the fluid levels asap (You're right, should have done this before)

 

[Evan A. Beck]

Where is your transmission temperature sender located? Are the gauge and sender working properly?



6-speed trans temp is dependant on ambient temperature. In the winter time around here, it takes me 1 hour and 50 miles to bring the temperature up to 100°. In the summer, when it is 70-80° out, the trans temp will get into the 140° range. If you are seeing 240° this time of year with an unloaded truck, I would check the oil level first... There could even be something misaligned in the transmission, causing excessive friction, resulting in high heat.

 

[b737jets]

it may be the temp sender... ... ... ...

if the oil looks fine

 

[kkreigh]

Some NV5600 six speed temps from my records for comparison:



75 mph/ air temp 55 deg/ load=empty/ trans temp= 135 deg



75 mph/ air temp 55 deg/ load= 13,000 lbs trailer/ trans temp= 155 deg



75 mph/ air temp 95 deg/load= empty/trans temp= 165 deg



75 mph/ air temp 100 deg/ load= empty/ trans temp= 175 deg



all on level interstate after 100 miles sustained driving @ about 1000 ft above sea level

air conditioner on on last two.



looks to me like your real high. Good Luck.

 

[FDNYMOPARGUY]

One thing to note about the six speed temps: while towing 7000 lbs. , I found that the transmission ran 30 degrees cooler ( 155 vs. 185) in 5th gear instead of 6th. Road speed was 60mph and ambient air temp was 80 degrees. Engine rpm was about 500 higher (2450+-) and cab noise was considerably louder. Boost was about 10 psi (5th) vs. 14psi (6th). Exhaust temps dropped 150 degrees to 550 in 5th (post turbo). Sorry for all the extra info, but it seems to illustrate that when towing, forgo overdrive - all other numbers look better at the higher engine rpm. BTW, I have one fastcooler installed on transmission and 3. 55 gears.

 

[monkfarm]

Thanks

I changed lube in the 6 speed, The right amount came out (about a gal) , and it looked fine!! Maybe the guage is screwed up. I'm trying the amsoil 5-30 series 3000 this time.

No one really talked about higher speeds (*80 and above) though, there seemed to be about a 30 deg difference between 75 miles /hr and 80. Mine takes a long time to get up to get up to temp(past 150 deg), and only started to come way up past 200 deg after hours of steady driving (I've learned how to use a pee bottle):--)

 

[kscheffler]

Fast Cooler Temperatures

I have a pair of fast coolers installed for about 6 months. I have never seen the temperature above 125F; which happend on a 5% grade at 90F ambient temperatures pulling a small load 2k pounds. Base on the other temperatures report in this thread it appears the fast coolers are working very well????

 

[monkfarm]

ordered fast cooler

The temp sender is in the (?PTO cover?) (The cover on the drivers side the bottom of which you take the middle bolt loose to drain transmission. )

I ordered "fast cooler" and received it. I couldn't wait for it to change the fluid so I did it, but I haven't been able to sustain 80 mph yet around Wisconsin where I've been driving it. But I'm going to get around to draining it again, and installing the fast cooler.