Towing with a 4l60e

[name]

Hi Guys,

I am towing with a new rig ( to me ) and after looking at some post that say not to tow with a 4l60e in OD I was wondering... Does that include the empty trailer ? I will be making a 300 mile trip to get a full size GMT 400 truck at highway speeds and would like to a least use the OD on the way there, would like to run 60-70 MPH to keep up with traffic .

I am towing a full lenght open car hauler but am not sure how much the trailer itself weights. Here is a picture of my set up. A stock drive train 1994 K 1500 with 5.7 tbi , 4l60e with 3.73 gearing the Previous owner did add Timberlins and Blizzacks shocks.


what say the experts ?

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[HotWheelsBurban]

Hi Guys,

I am towing with a new rig ( to me ) and after looking at some post that say not to tow with a 4l60e in OD I was wondering... Does that include the empty trailer ? I will be making a 300 mile trip to get a full size GMT 400 truck at highway speeds and would like to a least use the OD on the way there, would like to run 60-70 MPH to keep up with traffic .

I am towing a full lenght open car hauler but am not sure how much the trailer itself weights. Here is a picture of my set up. A stock drive train 1994 K 1500 with 5.7 tbi , 4l60e with 3.73 gearing the Previous owner did add Timberlins and Blizzacks shocks.


what say the experts ?

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What's the terrain like on this trip? Towing on flat ground is less stressful to the vehicle than towing on hilly ground. If I was doing this with my Burb, even though mine is a Vortec 5.7 and not TBI, and mine has 3.42 rear gears(C1500), I would used D instead of OD just to be on the safe side.
When we were towing a 5x8 Uhaul trailer, loaded to about 3000#(dry weight of trailer is ~1000#), from Houston to Austin, we were able to use the OD as long as we were on flat ground and keeping it under 60. Once we started getting into the rolling hills that are the eastern edge of the Texas Hill Country, we dropped it into D and had no issues. None before either, but a time sensitive road trip is no place to have transmission problems! The last two years, going to this particular car show and swap meet, we've been in my one ton crew cab, with a 4L80E. It tows fine on flat or hills, in OD, because it's a "proper" truck transmission (based on the Turbo Hydra Matic 400, built to go behind big blocks. The '60 is a good trans, it just needs a little more care of use than its bigger sibling.

 

[funnyfarm]

Hi Guys,

I am towing with a new rig ( to me ) and after looking at some post that say not to tow with a 4l60e in OD I was wondering... Does that include the empty trailer ? I will be making a 300 mile trip to get a full size GMT 400 truck at highway speeds and would like to a least use the OD on the way there, would like to run 60-70 MPH to keep up with traffic .

I am towing a full lenght open car hauler but am not sure how much the trailer itself weights. Here is a picture of my set up. A stock drive train 1994 K 1500 with 5.7 tbi , 4l60e with 3.73 gearing the Previous owner did add Timberlins and Blizzacks shocks.


what say the experts ?

You must be registered for see images attach

We own almost the same vehicle I have a 1995 Suburban 373 gears 5.7 TBI I had to rebuild my 4l60 I did use it for Towing after rebuild a change the way I tow I would take it out of overdrive and just run in third gear I had no problems also if you have time I would slap a transmission cooler on that bad boy that particular year did not come with a factory transmission cooler you can get one on AutoZone for under $35 super easy to install and it helps save the life of your transmission I also have a 98 K 1500 I drove it halfway across the country loaded down with a fifth wheel I never put the truck in overdrive and it had zero problems

 

[Scooterwrench]

Play it by ear. If the truck feels bogged down and is constantly downshifting with small increases of throttle input then drop it down into third. Even gas at current prices is cheaper than a tranny rebuild.

 

[1998_K1500_Sub]

Hi Guys,

I am towing with a new rig ( to me ) and after looking at some post that say not to tow with a 4l60e in OD I was wondering... Does that include the empty trailer ? I will be making a 300 mile trip to get a full size GMT 400 truck at highway speeds and would like to a least use the OD on the way there, would like to run 60-70 MPH to keep up with traffic .

Don't run with the torque converter unlocked for extended periods of time. It happens when towing, I've seen it for myself. If it's unlocked, it's pumping heat into the transmission oil and that's a Bad Thing™.

If you witness it happening, relax the throttle a little and it'll likely lock up, then you can tip in the throttle again to maintain speed.

I am towing a full lenght open car hauler but am not sure how much the trailer itself weights.

The U-haul auto transport trailer I use is around 2200# IIRC. The weight's listed on U-haul's WWWsite.

Your trailer looks a bit heavier.

The trailer will have very little wind drag.

You may be able to pull in OD just fine, unloaded, particularly on level pavement, but keep an eye on the TCC lockup behavior.

Here is a picture of my set up. A stock drive train 1994 K 1500 with 5.7 tbi , 4l60e with 3.73 gearing the Previous owner did add Timberlins and Blizzacks shocks.

My rig's similar, 1998 K1500 Suburban L31 5.7 4L60E 3.73 on 256/65-18s. The Suburban weighs ~6200# with me in the driver's seat, as reported by the grain elevator's scales.

I carry a 4000# car on a U-haul trailer occasionally, and almost always run in "D" (3rd). On level ground I did run for a while in OD just to see how it performed, and it was surprisingly good but I wouldn't recommend it.

BE CAREFUL, I “spun” the carrier bearings in my 8.5" rear once a few years ago while towing the car hauler; I guess I was too heavy on the throttle at the stoplights. It wasn't a cheap repair.

I have a 9.5" rear on sawhorses as I type this, and I hope to have it installed next week.

 

[Komet]

Maybe use D around town and then try OD when you're at speed and see how it does. It'll likely be fine with the unloaded trailer but gas money spent acquiring rigs doesn't count so its ok to do the whole thing in D.

 

[L31MaxExpress]

Food for thought. My 2nd 4L60E in my 97 van started losing the converter clutch shortly before the unit failed entirely. In OD at highway speeds it would set a P1870 code, enable the SES light and shift at maximum line pressure. I really did not care about the 4L60E POS at that point and just held it in 3rd which never set the P1870 code. Result, ZERO difference in MPG running 70-75 mph in 3rd compared to what it got with a healthy transmission in OD. The gearing GM put in a Suburban or Van with a stock 350 made overdrive practically pointless other than reduced noise. Drop it to 3rd and let it eat your 4L60E and its torque converter will thank you as will your engine. If the PCM sees too much load in overdrive it will go into soft PE then full PE if the load is maintained and dump fuel trying to make enough torque to maintain speed in overdrive as well. Does not take long running at an air/fuel ratio in the 11s to use more fuel than running at 14.7:1 at a little more RPM due to the reduced engine load. The later TBIs like yours have a catalyst overheat protection routine as well, run it at a high load for a while in PE and it will run even richer, into the 10s AF wise. The Vortecs will do it too. Vans and Suburbans should have had a 4.10 gear with the 4L60E even with the P235/75R15 tires on the 2wd 1500s, would have helped a lot of those transmissions live longer. The 4x4s with the taller tires should have had 4.30s or 4.56s especially ones sold in the mountains.

 

[L31MaxExpress]

Don't run with the torque converter unlocked for extended periods of time. It happens when towing, I've seen it for myself. If it's unlocked, it's pumping heat into the transmission oil and that's a Bad Thing™.

If you witness it happening, relax the throttle a little and it'll likely lock up, then you can tip in the throttle again to maintain speed.



The U-haul auto transport trailer I use is around 2200# IIRC. The weight's listed on U-haul's WWWsite.

Your trailer looks a bit heavier.

The trailer will have very little wind drag.

You may be able to pull in OD just fine, unloaded, particularly on level pavement, but keep an eye on the TCC lockup behavior.



My rig's similar, 1998 K1500 Suburban L31 5.7 4L60E 3.73 on 256/65-18s. The Suburban weighs ~6200# with me in the driver's seat, as reported by the grain elevator's scales.

I carry a 4000# car on a U-haul trailer occasionally, and almost always run in "D" (3rd). On level ground I did run for a while in OD just to see how it performed, and it was surprisingly good but I wouldn't recommend it.

BE CAREFUL, I “spun” the carrier bearings in my 8.5" rear once a few years ago while towing the car hauler; I guess I was too heavy on the throttle at the stoplights. It wasn't a cheap repair.

I have a 9.5" rear on sawhorses as I type this, and I hope to have it installed next week.

I crushed the pinon spacer and destroyed the pinon gear and ring gear in the 97 van unloaded driving it hard. IIRC GM called that rear an 8.6. Swapped a 9.5 in its place at the time. I am fairly certain the 4L85E grabbing 2nd @ 5,500 rpm with the torque management zero'd out and chirping tires at 50 mph did not help the 8.6s situation. I saw the rear tires break loose multiple times in datalogs going into 3rd at 90 mph too.

 

[L31MaxExpress]

Someone correct me if I am wrong, but aren't the 30 spline axle version of the 10 bolt an 8.6. I know the older 8.5s like my 1987 G20 has a 28 spline axle. I have a 92 G20 rear end currently apart that has a 30 spline axles. It has been years since I have had an 8.5 torn down, but the carrier bearings look larger in that 92 housing than I remember in the older housings I have had apart. I am working on setting up a 4.10 gear and Detroit locker for that 87 van that will go into it with a 200-4R swap. I will measure the bearing OD when I fully tear it apart and get the right ones, but looks like that 92 G20 rear is an 8.6 based on larger looking carrier bearings and 30 spline axles.

 

[99xcss4]

there are 8.5 30 spline 10 bolts I did not know that the 8.6 10 bolts were in vans and that they did not come out until the gmt800s came out I could be wrong here but I want to say that all 8.6 10 bolts have disc brakes and 6 lugs I do not know the axle spine count on the 8.6 you are most like right saying that they are 30 spine