4L60E towing temps

Status
Not open for further replies.
HawkeyeScott

HawkeyeScott

Joined
Jan 11, 2007
Messages
989
Location
El Oeste
Getting some summer driving in the 2008 Suburban 5.3 I bought back in January. The manual states that the normal operating range for this transmission is 180 to 200 degrees. But doing 70 mph on the interstate last week in 92 degree heat got it to 207.

What concerns me is that I'm about to start towing our 4200 lb. travel trailer up some steep mountain inclines in 90+ heat this summer. Now, the truck is rated to pull this trailer but I'm somewhat concerned about what I've seen from the transmission temps so far.

The dealership says a warning light will come on at 270 degrees. That's a far piece from 207. So, what temps and for what duration are okay? The fluid is new, for what it's worth, and I'll likely over service the ATF after installing a drain plug.
 
FWIW, this is the first truck I've owned that has a transmission temp. gauge. So as a BITOGer, it naturally gives me something new to worry about!
 
I would be concerned with towing and .... uphill with this transm.
Ever consider breaking the journey to cap the transmission temperature ?
Yes, shorten OCI as suggested.
On longer term, it may make sense to 'up' the oil viscosity grade for protection.
 
Install a much larger outboard trans cooler. Add a fan with controller and Magafine type filter. Stay out of OD in the tough spots.

What is your rear end ratio?
 
Last edited:
I typically take the pan off and change the filter on any used vehicle I buy or inherit. Usually the pressure line to the cooler is the bottom one, and return line the top one - a good way to get some oil out before dropping the pan and have transmission fluid pour on your head. Dexron VI is backward compatible and should work just fine. Use your gears and not the torque convertor stall when climbing hills. It's not a race to the top of the mountain, especially when towing with light duty vehicles.
 
I wouldn't be concerned until it starts going above 220-230. Definetly keep it below 250. You can combat temperature rise by slowing down ie dont bomb hills at 75 with 5000lbs.

The higher the temp, the more often you will need to change fluid. If you havent done so already I would change the fluid before I go towing.
 
I think that the transmission cooler and oil cooler were options in those years.. you might want to check to see if your vehicle has them.
 
Does your Tahoe have the tow/ haul feature?

It keeps you out of 6th gear and stretches your shifts out a bit.
 
If it really is a 4L60E, you don't want to tow in O/D, PERIOD! It'll destroy the O/D band pretty quickly (not to mention the ATF flow will be greatly reduced too due to low engine/pump speed). Highest temp I ever had on a 4L60E (actually it's older mechanical version 700R4) was about 220F, but I never was brave enough to pull a travel trailer with one, that job was always done by the 1 ton pickups.
 
TruCool LPD (Low Pressure Drop) is a good cooler similar to factory design but can go up a size or two. Space it close to radiator so it cools even when sitting in traffic (fan flow requires the tight spacing). You should have room for a Derale spin on filter near the cooler and with your drain plug - adios to pulling the pan. I'd use Gates transmission hose.
 
Without question, install a stacked plate cooler. I would use a Derale and see what size you can get behind the grill and in front of the A/C condenser. Doesn't need to be the largest cooler, but this one is a decent size.

http://derale.com/products/fluid-coolers...pt-ports-detail

The 4L60E is a fantastic trans, they just need some routine maintenance. Just something to add...if you are near the 150K mile mark, at some point I would recommend replacing the separator plate which sits above the valve body. The steel check balls over time will hammer this plate and eventually enlarge the holes resulting in pressure loss and if that happens, clutch failure is eminent. Many of them go much longer than that but 150K is only a reference point for early intervention but just some food for thought.

If you plan on keeping this vehicle, I would suggest also at some point installing a vette servo and a sonnax super hold servo which goes inside the round side cover on the pass side. Not hard to replace but increases holding power on the band without increasing line pressure....nicer shifts as well without being too harsh.

Back to your towing issue, I would get the stacked plate cooler and if you have an android, install the Torque Pro app which can monitor your trans temp. Most GM PCM's will provide the trans temp so I'm not 100% sure your Tahoe will, but my 02 Envoy will. You would just need a bluetooth dongle to plug into your OBD2 port...very useful tool.

Trans temps of 250 deg is bad, you would need to change the fluid quite often if it reaches those temps.

I also concur with the Maxlife or even Amsoil ATF, I have been using Maxlife ATF for about 130K on my 4l60E and it currently has 258K miles on it....no issues.
 
Originally Posted By: dlundblad
Does your Tahoe have the tow/ haul feature?

It keeps you out of 6th gear and stretches your shifts out a bit.


Exactly. Shifting generates heat, as does not having the lockup, well, locked up. Dropping it down a gear if you have the selection, and/or choosing the Tow/Haul mode will accomplish both.

When towing in the mountains, select a lower gear before starting up the grade; this will make the shift at a point where there is less stress/heat in the transmission.

207 isn't anything to worry about, but I agree with putting synthetic in.
 
Thanks, everyone. I did the AT filter when I got the truck. I've done 5 drain/refills through the aftermarket plug hole since then. Been using SuperTech Dexron IV to cycle out the old fluid.

I'll learn a lot today as we depart for our first tow in the next hour. It's 75 degrees (not 95) so I'm catching a break there.
 
Happy Trailer Trails
wink.gif
 
Originally Posted By: i6pwr

The 4L60E is a fantastic trans, they just need some routine maintenance. Just something to add...if you are near the 150K mile mark, at some point I would recommend replacing the separator plate which sits above the valve body. The steel check balls over time will hammer this plate and eventually enlarge the holes resulting in pressure loss and if that happens, clutch failure is eminent. Many of them go much longer than that but 150K is only a reference point for early intervention but just some food for thought.

If you plan on keeping this vehicle, I would suggest also at some point installing a vette servo and a sonnax super hold servo which goes inside the round side cover on the pass side. Not hard to replace but increases holding power on the band without increasing line pressure....nicer shifts as well without being too harsh.


The 2nd Clutch checkball does wear the plate, To the point of getting stuck in the plate quite often. But the checkball getting stuck or beating up the plate does not effect line pressure or cause pressure loss.
The ONLY thing a stuck ball will cause is the Band to drag during a forced automatic or manual 2-1/3-1/4-1 detent....This can shorten the life of the 2/4 Band.
If the ball is not sealing 100%....It can cause a hash/firmer 1-2 upshift, But NO other issues.

When installing a Vette/093 or larger 2nd servo piston, You need to install Inner Servo Cushion Spring GM# 8681195. This will calm the 1-2 shift down & allow a larger ratio boost valve to be used. The spring also helps with the infamous 3-2 down shift Clunk.

The Sonnax 4th super hold servo is a good piece! But you have to watch the band clearance VERY closely as installing this servo almost 100% of the time requires a longer apply pin. The Band Clearance specs Sonnax prints in the instructions is way off on the outer limit of .125"....You can run them as tight as .020" & no looser than .060" or you run the risk of a clutch timing issue between 2nd & 3rd gear.

As for the 4L60E being a fantastic trans, That is up for debate, It is a very simple 4 speed as it only uses 2 Carriers where most 4 speed overdrives use 3, They are very efficient far as frictional spin loss. Just about everything else about it's design is a compromise.
 
Last edited:
Originally Posted By: user52165
Install a much larger outboard trans cooler. Add a fan with controller and Magafine type filter. Stay out of OD in the tough spots.



I was also thinking about an external cooler . Did not think about a fan .

God bless
Wyr
 
Status
Not open for further replies.

Similar threads

HawkeyeScott
  • Locked
Shopping for a transmission cooler
2
Replies
23
Views
8K
DoubleWasp
AZjeff
  • Locked
Tranny temp while towing too high?
2
Replies
23
Views
8K
SteveSRT8
HawkeyeScott
  • Locked
Downside to running 75w-140
Replies
11
Views
3K
Y_K
BobsArmory
  • Locked
Average tranny temps when towing??
2
Replies
20
Views
7K
Colt45ws
I
  • Locked
Measuring Tranny Fluid Temperature....
Replies
15
Views
7K
Leon
Back
Top Bottom