1st gen cummins temp.

firetoy

firetoy

Well-Known Member
Joined
Apr 12, 2006
Location
lincolnton
well i pulled about 5500 pounds today and i notice that it was getting a little hot. about 2/3s the way on the factory gauge. is that a common thing. or should i be concerned? also on other trucks i have always turned the overdrive off. i did that today on mine and it seemed like i couldn't go over 60mph. do i need to turn it off on this tranny. it seemed to pull fine with it on.
 
get a real gauge, the factory is useless.
 
Radiator may be old and now passing heat well. Mine did that too.
 
my bus runs around 200-210, pulling or not. you need to get a real guage though, i've had three 81-93 gas trucks and none of the guages were very accurate.

with the OD off, you're probably gear/rpm limited to that speed.
 
firetoy said:
so did getting a differant rad. help.
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Yup!

Pulling to Texas grossing about 21-22k (32' trailer and 2 rigs at *ahem* slightly elevated speeds), we were OK until the A/C went on going through the rolling hills of central texas, then it started to run warm.

Months later, (last summer), it would run warm pulling just the cruiser on my 16' trailer up I-40 just doing 70-75.

Dropped the $300 on a new radiator, and I can't make it run hot since.

I've also heard that it's a good idea to change out the thermostat at the same time, but only to use the cummins ones, there are issues with the parts house ones.

The truck is meant to pull with the O/D on, and like Rufus said, you're getting into the RPM's where the governor is pulling back fuel at 60 or so. Do run it in O/D, but hold off on letting it go into OD until 50-55 mph. around town, I always have O/D locked out.. Advice from my DTT transmission builder .
 
The "3200rpm spring" (Bosch #366) will let the horses loose when pulling w/o the OD. Mine used to defuel @ 2500rpms... now will PULL to 3200+ before defueling :D

We loaded mine last Tuesday w/ approx. 8000# for a "test run" from Rural Hall to King...

Unfortunately, the tranny temp immediately went to 220* :rolleyes: Since the gauge & sender are brand new Isspro units, I need to check it with an infrared for consistency... it may be that 220* is normal (sender in the cooler OUT line)? Also, appears the fuel screw got back OUT when doing the spring and needs to be twisted in a few turns minimum. Since there wasn't time to tweak & test before our Wed. AM departure (didn't want the EGTs to go through the roof 10 miles down the road!), we cross docked everything into my brothers 2500HD (BB gasser... OUCH! ).
 
220 sounds feasable for a hot day, if the TC is unlocked. (Don't some 1st gen's not have locking TC's?)
 
FYI: if you are using the stock gauge it should not be 2/3 HOT.. mine hardly ever even moves..

the hottest I have ever gotten was 1/3 and that was at 70 with 16,000lbs in the hills...
 
I know for the 24 valves, two thermostats are available, a 180 and a 195 i beleive, or somewhere around there. Not sure if its the same on the 12 valves. My old 24 valve would get a little warm, half way between the middle mark and the beginning of the hot mark if i held it above 3 grand for miles on end in the mountains pulling a good load......stupid 5 speed, 3rd gear was too low and 4th was way too high, had to let it scream away in 3rd.

Put a new thermostat in just to see if it would make a difference, gauge hardly ever moved off middle way after that.
 
Maybe a fan clutch. They are very dependant on them because of the low rpm's.

When I ran egt's at 1100 for long the temp would rise to 205 - 220
 
Rich said:
220 sounds feasable for a hot day, if the TC is unlocked. (Don't some 1st gen's not have locking TC's?)
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From what I've found on DTR & TDR... ALL 1st Gens are non-lockup. However McMopar found my valve body to have all the needed holes/machining to accept the e-lockup solenoid (just no way to make it work short of full tranny replacement :( )

I think 220* off the output to the cooler *could* be acceptible, but need to check into it further.
 
justjeepin86 said:
I don't know whether this is right or wrong, but I was told that no 1st gen had a lock up.
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I dont understand how a transmission holds together without a lockup converter. Isn't the heat generated by the converter slipping all the time hard to deal with? My current truck is an auto, the only time i feel it really pulls good is when the converter is locked....
 
Oh yeah, Stump hit it too.. were you hearing the cooling fan? it makes quite alot of noise when it's engaged, you should know it.
or, shut the engine down and try to spin the fan, you shouldn't be able to.
 
Mines a 90 and gets 2/3 's up when I hit an exit ramp off the highway, but drops as soon as I hit the skinny. Factory gauge isnt very accurate.
 
temp

thanks guys for all the help. i will try a thermastat today and also check the fan. then go from there. i was pulling about 2000 pound enclosed trailer up in VA. i was having a hard time holding 65 up some of the hill on I 77. i haven't done any mods at all. do you guys think that is normal? i spose running a little hot doesn't help any. i just know my gmc with the 6.0 would have no prob. i was a little dicouraged

i took some pics of my gauges while i was truckin.

also is that a normal oil presure?
 

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I wouldnt be too discouraged by its performance. In stock form the automatic first gens werent the strongest thing around. They have huge potential, and are dead reliable, but its still a 15 year old truck that is gonna take some TLC.
 
cummins

so turning uo the screw and a air filter should make a huge differance?
 
Also, opening up the exhaust will help it run a little cooler, most notably on the EGT's though.

Gauges first! (I kinda agree that your factory gauges probably aren't being very accurate, especially the oil pressure...
 
Here is what I recommend if you want to turn it up..

1st get : Pyro gauge and tranny temp, the boost and tach are not as important.
2nd: either get more open muffler or get rid of it..
3rd: put BHAF (big air filter) on truck
4th: read how to turn up inj pump on DTR in 1st Gen section..
you can turn up power, smoke, idle, etc..
and yes you can turn these up where you can smoke the rear tires.. but with a auto tranny i would be more careful.

I have done these and my truck can pull anything and it wil get up and go for a 15 year old truck :)
 
sounds good.

sounds like a good plan of attack. first thing is gauges.

today i drove to charllote empty and it never went over a 1/4 on the factory gauge. so i think an engine temp and oil preasure will be first gauges. i got a huge air filter. i spouse it wouldn't hurt to install that. then before i turn it up i will get the rest of the gauges.
 
BRUISER said:
Here is what I recommend if you want to turn it up..
1st get : Pyro gauge and tranny temp, the boost and tach are not as important.
2nd: either get more open muffler or get rid of it..
3rd: put BHAF (big air filter) on truck
4th: read how to turn up inj pump on DTR in 1st Gen section..
you can turn up power, smoke, idle, etc..
and yes you can turn these up where you can smoke the rear tires.. but with a auto tranny i would be more careful.
I have done these and my truck can pull anything and it wil get up and go for a 15 year old truck :)
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...add 4" downpipe to that list...:)

...and 3200 spring...:)

...and tweaking the throttle linkage...:)

...and a tow/play switch...:)

...and a compressor housing upgrade...:)

...and...and...and...

Greg
 
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