I am a new Blazer owner and tow a 4400 lb travel trailer with my 03 Blazer LS (4dr 2wd). It seems to tow just fine. I have all the proper towing equipment, ie: WD hitch, sway bar, etc. My question is that I have seen overdrive referred to on this forum and I don't have overdrive on my Blazer so I tow in D. My owners manual doesn't even mention overdrive. Am I missing something?

 

Your Blazer has a 4sd automatic with overdrive. If you typically tow on flat ground, you shouldn't have to worry about what gear its in. If you tow in the hills, you should be driving in 3rd gear.

If you are towing a lot, you should have an auxilliary transmission oil cooler on your truck. 4lowlife had posted pictures of the cooler that him and I put on his truck awhile back. CLICK HERE for some pictures and explaination. You may want to go with a larger cooler (11x14) since you are towing a decent load a lot more than the rest of us.

 

swartlkk

Thanks for the info. I don't know what the 4sd transmission is but now I can do some research and learn about it. I do plan to put a transmission cooler on the car, well have it put on, I am not as handy as you and your friend obviously are.

I have only had one tow so far, of 60 miles, with the Blazer and it seemed to do fine. It is rated to tow 5500 lbs and the trailers dry weight is 4400 lbs. That gives me 1100 lbs to tinker with.

Thanks again,

Terry

 

Hello Terry,
You have a 4L60e tranny. It is electronically controlled and the upgraded version of the 700R4/4L60 tranny from earlier years. Yes, it is a 4 speed tranny. 1st gear is lower then most auto trannies and is 3.06 gearing. 2nd gear is like 2.something, and 3rd gear is 1to1. In other words for every revolution of the engine the tranny turns once. 4th gear is where this tranny is better then most, it ahs a 70% reduction in 4th gear, commonly called overdrive and is usually indicated ont e shift column by D with a circle around it. D without the circle is 3rd gear. GM put this tranny in all, let me repeat thet, ALL 1/2 ton trucks and lighter. Yes, all fullsize 1/2 ton trucks, includeing Suburbans, Tahoes, etc. This tranny is the work horse in GMs line up. This tranny started out in the early 80's as a 700R4. Had reliability problems, however by '87 GM had fixed all those issues. Then gM changed the vavle bdoy (what controls the fluid cflow in the tranny) and called it a 4L60, then they changed to electronic control so the computer cna make the engine and tranny work together even better. and they called it the 4L60E tranny. Then in '98 GM made another change and made the belhousing removeable, this makes the tranny even more flexible, it can now be easily bolted up to just about any engine with the right bellhousing adapter. With a few exceptions, all of the internal clutch assmblies that are in the 700R4 will work in teh 4L60E. In fact when I rebuilt my '00 4L60E tranny I took my clutch plates and used them in my '87 700R4 tranny.

Sorry for rambleing, hope that helps you in your search for more knowledge.

 

After saying all that I forogt why I posted in teh first place.

Get the tranny cooler before you go on your next trip.

The #1 reason auto trannies fail is due to heat. Towing generates tons of heat, get the cooler. The tranny you save will be your own...

 

Real man of genius that posted to you tbrinker. welcome to the forum.

 

Hanr3,

Wow! Thanks a lot for the information. I now have a much better feel for what my transmission is. I really appreciate your input. I am trying to ensure that I have all the correct equipemt to tow my RV safely and the transmission was one of my areas of concern. I have asked about towing my travel trailer with my Blazer on the Good Sam RV forum and almost everyone said the Blazer is not a strong enough vehicle to tow anything but a little pop up. The problem I ran into is the every single experiencedc tower I spoke to in person told me the Blazer would tow my trailer just fine. Thus the delema. I even had my rig inspected while, hitched, before and after my one and only tow and those people said they saw no problems. I even talked to my local Chevrolet dealer (Castriota Chevrolet in Hudson, FL) about getting a bigger tow vehicle and explained why I was looking and the salesman told me that while he would be more than happy to sell me a new vehicle the Blazer would tow my trailer with little difficulty. And, yes I plan on installing a transmission cooler soon.

Thanks again,

Terry

 

Your welcome.

Just remember your towing and not in a race. If the tranny starts to hunt for gears. You need to change something. Slowing down is the best, downshift manually to 3rd is good. Most will recommend you tow in 3rd gear (shift selector in D). And if you are in hills, stop and go traffic, strong head winds, etc. Yep do it. If your on open flat highway with little wind, upshift to OD. If the tranny starts to hunt for a gear, shifts up and down, up and down. Slow down or manually downshift. ITs not a race. I get great satisfaction passing broke down rigs that past me earlier.

Keeping the tranny cool is the best way to make it survive.

Something I didn't mention before and have the time to do so now. Your tranny also has a locking torque converter feature. The torque converter is what attaches to the engine via the flexplate, and links the engine to the tranny input shaft via hydraulic fluid. There is no mechanical connection between the tranny and engine with an automatic tranny, its a fluid connection. The faster you go the more the torque converter will slip. That slippage is creating tons of heat. If your torque converter doesn't lock up and you drive on the highway in the summer, you can fry your tranny in a matter of hours. That's how much heat it generates. Faster if your towing. The torque converter will lock up in 3rd and 4th gears, basically when you get over 45mph. This reduces the heat generated to almost nill. What does lock up mean? Simple, for every revolution of the engine the tranny makes the same number of revolutions. There is no slippage, no slippage = no heat generation. Plus this lack of slippage means better fuel economy. The lock up is controlled by your computer. It gets its info from various sensors. The lock-up will disengage if your tap the brakes, slow down, or go past 3/4 trottle (passing gear). It will engage once you are over 45mph, and are at cruising speed. Watch your tach. It should drop by a couple hundred rpm when the torque converter locks up.

The major difference between driving in 3rd gear and 4th gear (overdrive) is fuel mileage. Your engine will turn at higher rpms in 3rd gear compared to in 4th gear going the same speed. Yet, while in 3rd gear the tranny won't hunt for gears as much. When the tranny is hunting for gears, the torque converter isn't locked up. This is why GM recommends towing in 3rd gear. Less likely to fry a tranny.

If this doesn't make sense or you have questions. Post up.

 

Hanr3,

Well thanks again. You are a wealth of information. I know more now about my transmission that I ever thought I would. Well I don't really know more, but because of your posts, I have the information at my fingertips.

One thing that I am not sure that I made clear is that my Blazer does not have the D with the circle around it.

Thanks again for the info.

Terry

 

Your gauge cluster should look something like the attached image below. You should see P R N D 3 2 1. 'D' is overdrive and '3' should be used when your trans starts to hunt for a gear when towing.
[IMG]local://upfiles/667/7D1BCFD414CC4847AA126475A8C8D3D6.jpg[/IMG]

*Image from the 2003 Blazer owners manual - Courtesy of MyGMLink.com - Sign up for free!