Need the Facts on my A518 transmission.........
 

My 93' club cab 4x4 has a A518 automatic in it. The transmission is bone stock and has never been messed with. The engine is pretty stock except for the 3200 gsk and a BHAF. The pickup currently has 201,000 original miles. I will be towing a car trailer next month for the very first time with it. The car on the trailer weighs a little over 3200 lbs. Here are my questions/concerns:

When can I use Overdrive while towing this car/car trailer?

When should I not use Overdrive while pulling the car trailer loaded?

What is a safe cruising speed for my pickup (good for engine/transmission)?

Are all A518 auto's non-lockup from the factory?

1-Use overdrive if you can keep rpm near the power band---1700-2000
and if it is not lugging or shifting a lot.
2- see number 1
3- run it as it wants to go--mostly by rpm
4- I thing so as far as the Cummins aplication goes. ( I have a 92 Dakota with the 518 but it is a lock-up unit.

What j-fox said. ;)

I'd keep up with the EGT's when really working it. Continuous 1200*F is OK with NO lugging (but I wouldn't if I could). ;)

With a stock transmission and torque converter it's down-right impossible to lug the engine! You'll most likely shoot the rpms right up to around 2000 (or more since you have the 366 spring) and it'll just stay there no matter what. You'll know when to back off by watching your water temp (if you don't have a transmission temp. gauge). The transmission heats up due to the sloppy torque converter and all the heat goes into your cooling system via the heat exchanger on the passenger's side of the engine.

At least this is my experience.

Oh, and I forgot to add:

I've never had any issues towing my fifth wheel in O/D. I kick it down to 3rd climbing the passes here in Colorado when my speed reaches about 55 or so. I just tore my transmission down (toasted front clutch) and the O/D section looks perfect. So I think I'm not hurting it in the least by doing this. The real enemy is heat!

Thanks for the replies guys! I am pretty cautious about my stock transmission being able to handle a simple job (pulling a car on a trailer). I actually have a temp gauge that I will be installing soon. I feel a little better being able to monitor my trans temp while driving. How many trans coolers are equipped on my 93' LE? I noticed one up by the radiator and another one under the bed. I have a trans temp sensor adapter that will tap into the 1/2" line going into the "under-bed" cooler.

The trans fluid leaves the trans fluid pump and goes to the heat exchanger under the exhaust manifold. This helps warm things up quickly on those really cold days. It also helps cool the fluid should it go hotter than the engine coolant.
From there, it goes to the little radiator up front. All the auto's have that OEM.
From there, it flows back to the trans. . . . . unless you have the optional cooler under the bed. If you do, the fluid goes there, and then back to the trans.

You'd see the actual hot fluid temp attaching the sensor to the line from the trans to the heat exchanger.

:)

Yes, I do have the auxillary "super-cooler" under the driverside of the bed. Hhhmmm, so maybe I'm a little confused on where to tap into the trans lines for my gauge to get the most accurate reading. I thought the outlet line from the trans goes into the remote cooler under the bed? Shoot.......I need a trans schematic for the 93' LE equipped with auxilary underbed cooler.

You've got me there. I assume (check spelling) the fluid flow with the aux cooler.

I'm sure those who know better will post. [redface]

Here is my idea...........
 

This is the homemade adapter that I will be using to make the trans temp gauge work. Anyone have a good suggestion on where to place it?

Anyone have an idea on where specifically to tap into the trans line for the sensor?

Climb under the truck, driver's side.

Looking at the driver's side of the transmission body, you'll see the shift linkage.


Just forward of the linkage, on the side of the trans body, you'll see a metal line that goes around and under the torque converter, and to the heat exchanger under the exhaust manifold. It's that line with the brass temperature sensor built in.

Attachment 74091

Attachment 74092

That steel tube is the hot trans fluid as it leaves the trans on it's way to be cooled.

That's where you need your sensor if you can't mount it in the pan. :)

I think I get it.......
 

BC847,

Thanks so much for posting your response and pics! You definitely clerified things for me and where they are located. I noticed in the last pic (showing metal outlet tube).......it appears to transition into a rubber line, is that true? If so, my fitting pictured above is designed for splicing into a rubber hose. Perhaps I can install it between the metal outlet tube and the block mounted cooler? Correct me if I'm wrong......[coffee]

No, that rubber hose is where I converted from worn, leaking metal tubing. Sorry.

Perhaps you can exchange the hose barbs for flare or compression fittings to fit the steel tubing. :)


FWIW, in that first image, the hose at the right of the image, that's the fluid Return to the trans. ;)

Hhhmmm.......I was hoping to use barb fittings to make things simple. I guess I'll have to re-think my plans. :(