Does anyone here have first hand experience towing with a Buick Roadmaster wagon?

patgizz wrote: there are zero wagons with the 7.5" rear end unless someone jammed a 91ish sedan rear under it. it is possible to flex the outer control arm bushings enough to do so and the spring perches are close enough that the springs sit on them. i've seen one sedan rear in a wagon and one wagon rear in a sedan before.

Actually, early box wagons could be had with the 7.5. Rare, but they're out there, and occasionally those axles end up in newer wagons. I've personally seen two 7.5s with wagon perches and pivots, both on pre-'85 wagons.

So I did a bit of tire research. Roadmaster wagons came with 225/75/15 as standard size (according to TireRack). 235/70/15 would probably work too. Most of the tires available in those sizes today are for trucks or crossovers. None that TR listed were D or E rated, but I'm sure something suitable can be found.

Also, the towing package is supposed to come with air leveling rear shocks.

My Roadbastard is a '96 with the tow package. As a tow rig it has pluses and minuses.

First, you probably don't need to go to LT tires. Just bumping up from the stock 225/75/15s to a set of 235/75/15s will add nearly 800lbs of load rating to the tire package. The small bit of extra diameter doesn't hurt, either.

Use a quality rear shock, or at least have the leveling system checked out. Probably best to go with a good shock in the rear, though. By the way, changing the rear shocks is a HUGE pain in the butt.

By the numbers, the Roadmonster should be a good tow rig. But the numbers don't tell the whole story. When I am towing my F500 on a 5 x 10' trailer with maybe 80lbs of tongue weight, it's magic. The entire trailer hides behind the car's frontal area, and tows like it isn't even there. When I tried towing my 6 x 12 enclosed motorcycle trailer (6.5' high) it was FAR less happy. As Curtis mentioned, the front of the trailer was like a damn sail. It was just a huge, square wall that had to be dragged through the wind.

I think that's the downside to towing with the RM. It punches a car-sized hole in the air, and even though the weight equation may work out fine, the aero equation is working against you. Honestly, my FWD Chrysler minivan towed the enclosed trailer WAAAY better than the Buick.

But for anything that fits within the slipstream, it's a beautiful thing indeed.

JG Pasterjak wrote: But for anything that fits within the slipstream, or is somewhat aerodynamically designed itself, it's a beautiful thing indeed.

FTFY.

We used to use one to tow boats that while on the trailer were much taller than the RM. No problems at 65-75mph, but I would not like to tow an enclosed trailer with just about any car.

mtn wrote:

JG Pasterjak wrote: But for anything that fits within the slipstream, or is somewhat aerodynamically designed itself, it's a beautiful thing indeed.

FTFY. We used to use one to tow boats that while on the trailer were much taller than the RM. No problems at 65-75mph, but I would not like to tow an enclosed trailer with just about any car.

Yeah, fair enough. Bottom line is with the Roadbastard it's not a matter of power or capacity, it's airflow management. Heck, maybe a RM with some badass spoiler near the back would be the best tow vehicle ever.

Does camping involve mountains? If you are going up a mountain or cross country with hills the Roadmaster probably won't cut it. Flat areas can have wicked cross winds. As others have stated, the Roadmaster probably isn't the best choice. I second the Suburban, but get the 2500 with LT tires.

I had an 2001 Suburban with the tow package. I burned up the 4L60 towing my boat across the Everglades which are pretty darn flat. Granted the boat was probably 10k pounds, but the overdrive just couldn't handle the load. I was able to limp it home in drive, but had to rebuild the transmission. Traded that Suburban in for a 2500 Suburban (3/4 ton) with the 4L80 and no more transmission issues.

FWIW, the 2500 came wired for electric trailer brakes, but I used the mechanical one on my boat trailer.

HappyAndy wrote: In reply to bigev007: I'll look into that, but I suspect that the cost would be prohibitive. I've looked into motorhome rentals before and found that the cost was higher than I would like, and the mileage restrictions made it pointless for long trips.

My parents have taken my kids on a summer RV trip for the past 5 years. Every year they use Cruise America and have had zero mechanical issues. The RVs are well maintained and pretty clean, considering they are giant rental cars. Pricing looks to be about $100/day and $.34/mile.

In reply to maj75: So you exceeded the maximum tow rating by 3500lbs and then drove a few hundred miles in Florida heat IN OVERDRIVE? You really can't blame the truck for failing you on this one man, that was on your driving.

In reply to maj75:

It's pretty common knowledge you should never run a 4L6x/700R4 in OD when towing or hauling heavy loads.

The only difference between 3rd and 4th in a 4l60 is the band being applied. The same clutch packs are engaged in either gear.

How does towing in 4th damage ANY transmission? It's not like 4th gear just starts slipping while you're cruising down the road pushing 100hp through the trans. That's not any different from mild acceleration in an empty truck and THAT doesn't break 4th gear. It's not like the trans necessarily generates more heat just because you're pulling something. If you're in converter lockup, it's not generating noticeably more heat then if the truck were unloaded. So how does towing hurt 4th gear?

It only hurts it if you are shifting it under power frequently. You control the amount of heat and torque the trans is subjected to with your gas pedal and shifter. So just learn how to drive it and use the driver mod to be able to use all your gears without breaking anything.

In reply to Vigo:

I forget why, but they're known to get real hot if you do.

what I've been told is that GM 4 spd OD transmissions bypass the cooler when in OD. The trans gets good and hot getting up to speed, then doesn't get a chance to cool back down. IDK why, and IDK if its only GM.

HappyAndy wrote: what I've been told is that GM 4 spd OD transmissions bypass the cooler when in OD. The trans gets good and hot getting up to speed, then doesn't get a chance to cool back down. IDK why, and IDK if its only GM.

This is why. At least from what I remember from working on them, there is still some flow through the cooler, but it's negligible compared to operation in all other gears. Less pumping loss = more mileage, was GM's thought. They've been doing that since the 2004r and 700r4 days.

That can be modified out if you really don't think you can driver mod your way out of burning it up. I am really resistant to devolving from 1980s technology to 1950s technology (3spd non overdrive) out of fear of something you are in control of. You control the heat in the transmission. You can always put a gauge on it if you are really worried about not being able to tell whether you are hurting it or not.

When i worked in a transmission shop it was right in the time period before 5 and 6spd units were hitting the rebuild shops (still too new) so the vast majority of what we did was 4spd truck units. ALL the common truck units burned up 4th gear under constant towing use including ford and dodge, even including the 604/606 transaxle units from dodge cars like what i've towed with which have a RIDICULOUSLY weak 4th gear clutch pack. It DOES all come down to heat but it DOESNT all come down to cooler flow in a particular gm unit. It was the most common issue among heavy towing with all the popular 4spd units other than maybe the 4l80 (we didnt see many of them, they're good!).

I guess i am ok with playing it safe but the whole reason i ever took a job in a trans shop was because i didnt want any part of the car to seem like a box of black magic i was afraid of, and now i'm not afraid of my transmissions and i'm not afraid im going to burn up 4th gear during towing and i wish noone else was either. You can learn to drive around it.

Vigo wrote: You control the heat in the transmission. You can always put a gauge on it if you are really worried about not being able to tell whether you are hurting it or not. When i worked in a transmission shop it was right in the time period before 5 and 6spd units were hitting the rebuild shops (still too new) so the vast majority of what we did was 4spd truck units. ALL the common truck units burned up 4th gear under constant towing use including ford and dodge, even including the 604/606 transaxle units from dodge cars like what i've towed with which have a RIDICULOUSLY weak 4th gear clutch pack. It DOES all come down to heat but it DOESNT all come down to cooler flow in a particular gm unit. It was the most common issue among heavy towing with all the popular 4spd units other than maybe the 4l80 (we didnt see many of them, they're good!). I guess i am ok with playing it safe but the whole reason i ever took a job in a trans shop was because i didnt want any part of the car to seem like a box of black magic i was afraid of, and now i'm not afraid of my transmissions and i'm not afraid im going to burn up 4th gear during towing and i wish noone else was either. You can learn to drive around it.

You and I have a LOT in common

Nearly all of the damage that happens in an automatic is during shifting... just like with a manual clutch. There is zero wear when its disengaged, and zero wear when its fully engaged. Its the slip and wear that eats away from friction.

There are so many thousands of possible things going on in there; pump pressure, solenoid actuation, valve body tune. I have fried 4L80Es being careful, and I have kept an E4OD alive for 130k towing 10k lbs behind a modified powerstroke. Its how you drive it.

If a range is selected in an automatic and the clutches aren't slipping, you can drive forever in whatever gear you want. As soon as the torque overcomes that grip, things will go downhill fast. That includes automatic shifts. If you are towing with your foot to the floor up a hill, you have to know where your downshift points are going to be. If you just keep your foot to the floor and let it downshift, you are applying maximum oomph while the clutches disengage and engage. Its like powershifting a manual and expecting the synchros to not wear out. Or like towing a barge with a manual and not letting up on the throttle when you clutch to shift. You are maximizing wear on the clutch.

The 700, 4L60E, and other variants are fine for towing. You shouldn't overcome the torque-holding ability of the clutches with the torque produced by any of the engines offered in front of it, provided the circuit is getting adequate pressure.

The reason I don't recommend towing in OD is this: 1) the cooling circuit has reduced flow. As long as the TC is locked (and holding) and the band isn't slipping, you're fine. But the OD band has significantly less friction than the clutches. Its pretty easy to overcome that brake torque. 2) With most of the rear axle ratio options in the B-body, OD is entirely useless when towing. At 65 mph, even very small throttle inputs will take you out of OD. Sure, you might get 1 more MPG in OD, but you'll spend so little time using OD that its pointless. 3) GM's overdrive autos use a planet set to overdrive the direct drum. It basically just uses input shaft speed and increases speed of the rest of the tranny by 30%. That means the tranny is generating 30% more parasitic heat. Transmissions like an A518 put the OD in the back. Once OD is engaged, the transmission slows down the same as engine RPM.

In short... You can tow in OD with a 4L60E, but only if you are psychically linked to the ECM, and only if you want to try and salvage 0.04 MPG at the risk of shaving 50,000 miles off the life of your transmission.

Really. Just don't. It always amazes me that people will try to save $3 in fuel at the risk of $3000 of transmission repair. Tow in Drive. Period.

Can the 700R4/4L60E be modified to allow full cooling in O/D?