Engine/Transmission (1994 - 1998) auto trans longevity advice

[CEdwards]

Not trying to start a manual vs. auto debate just wanting to hear from someone with similar truck and miles. My 94 auto was rebuilt at 150000. I was wondering how much life I can expect out of it or things I can do to make it last. The previous owner changed and flushed trans every 10000. He pulled 30' fifth wheel for most of first 180000 then I bought truck. I will pull gooseneck maybe once a week and drive highway miles everyday. Was wondering if way to tell if he may have upgraded TC during rebuild. Truck stock as far as I know.





Thanks for the info

 

[Lsfarm]

Difficult Question

CE, your question is a difficult one. The longevity of an automatic transmission hinges on many items.

First, how well was the overhaul done?? Merely to stock standards? or to the standards of an upgraded performance transmission?? Was the Torque converter replaced ??



If the trans is up to the task, then you can do a few things to help it live longer. First is to keep the rpm up on the engine, which keeps the pressures up in the trans. What you don't want to do is to drive around at less than 1800 rpm when pulling a load. Keep the OD locked out untill you will be at at least 1800 in OD. If you have 3. 55 gears this will mean you will be at around 70 mph which may be faster than you care to tow. If you have 4. 11 gears you are in luck.



Keep the ATF under 220 degrees and keep the bands adjusted. You may have many trouble free towing miles.



Pm me if you have more questions



Hope this helps. Greg L

 

[CEdwards]

I have a light on the dash for ATF temp. Anyone know at what temp the light comes on?

 

[rrausch]

That info might be in your Owners Manual. A lot of stuff is and most people don't read them. I actually did read mine, when I got my truck, and was amazed at the little pearls of Dodge/Cummins wisdom tucked in amongst all the other stuff I already knew.



Lsfarm covered most of the basics. Guys have gotten over 200,000 out of their stock auto trannys. It is all in how you drive it, and whether or not you service it. I change my transmission fluid & filter every 12,000.

 

[hammersley]

I have 165,000 on my stock one - and still going strong..... Had a VA for 120,000 miles and the remainder of my mods for only about 5,000.

 

[Howard Durand]

I have about 100K on my transmission. Early on, I replaced the torque convertor with a BD low stall convertor and enhanced valve body.

The valve body wasn't quite what I liked at the time but BD later reworked it and I am very happy with it now.



With the 3. 54 gears that I have, these modifications seem to work pretty well along with power increases gained from the fueling modifications I have done.

I only tow a 30 foot travel trailer that is rated at 7,000# so, fully loaded, my total combined weight is around 15,000#

I use Red Line synthetic ATF and watch the temperature closely.

I am confident the transmission will last many miles yet.

If it does give up, I'll go for one of the aftermarket replacements.

 

[CEdwards]

Is there any way for me to tell what kind of TC I might have by taking off the dust cover on the bell housing. It was rebuilt by previous owner and I was hoping maybe he fixed it a little better than it was??

 

[CEdwards]

rrausch, I looked all through the owners manual page by page and no where does it say at what temp. the atf temp. light comes on. I was curious to know if the light will come on before it's too late or like most "warning" lights they're totally useless.

 

[Joe G.]

According to my '95 service manual the temp sensor light comes on at 280°.



If you find a drain plug in the TC it ain't stock.

 

[hammersley]

If the light comes on at 280 degrees - That's Way To Late!!!!!

 

[Joe G.]

Yeah. That's exactly the reason I have a trans temp gauge.

 

[Howard Durand]

I think a stall test would give you a pretty good idea if your converter is stock or not.

My stall speed was about 2350 rpm with the stock converter and 1900 with the BD converter.

 

[fortunate1]

Joe G. said it...

Take off the 3 hex-head (5/16"?) screws that secure the dust cover. Use a large flat-head screwdriver to turn the t/c tooth-by-tooth all the way around until you: A) find a drain plug, or B) end up where you started without finding one. A) = aftermarket t/c. B) = probably a stock one.



I went about 110K miles with the stock transmission. Power mods were #6 TST plate and 215 injectors. At 110K I put in a 1st gen DTT v/b (right after Bill K. started out on his own). That changed the shift points and raised the fluid pressures; it helped a lot. At 230K I decided that things were starting to slip a little, and put in a DTT master rebuild kit, t/c, v/b, and 4K GSK. The difference is night & day. Now the power gets to the wheels, and does so in the Cummins' optimum rpm range.



The key to a transmission's long life is 3-fold, I believe.

Quality & Workmanship of the transmission & its components

Proper service and fluid change intervals

How you drive it

A "lesser" quality (stock OR a lousy aftermarket job) transmission, parts, and installation will not last as long as the top quality ones that are frequently the source of much debate, but all seem to perform.



Leaving the ATF in for too long will subject it to too much heat, debris accumulation, and age/wear. Change the ATF regularly; it's cheap insurance. In some instances, you can even move from the expensive ATF+3 or +4 to Dexron III. I have changed to Dexron (2 changes now) with no effect on the transmission. 4-1/2 gallons per change adds up quickly in the wallet.



Drag racing should only be done when absolutely necessary: like when you're at a stop light and there's a 2-to-1 lane bottleneck about a 1/4 mile ahead. An aftermarket transmission will allow you to tow without slipping because of the higher fluid pressures and an efficient t/c. Both of those will keep fluid temps down, and that will lengthen the service life you can expect from your transmission.



Install a dedicated transmission temp guage to monitor the ATF temps while you drive. The idiot light will illuminate at too high a temp to do you any good; the ATF will get too hot and the damage will already be done.

 

[rrausch]

CEdwards, yeah, mine is a '95 also, and my manual also states 280 degrees, sorry for the delay in answering.



A transmission temp guage is pretty cheap ins. When I first got my truck the gauge was already installed and I was seeing a lot of 340 degree readings. Yikes! So I crawled under the truck and put my hand on the trans. pan. It was only warm to the touch! The problem was the temp sender had a bad ground! After I fixed that, I hardly ever saw readings above 160. After I had my Trans Bombed, my temps went down. Now I seldom see them above 145.

 

[jburnes]

I set up a aux cooler with a fan. It comes on at 180 degrees and I have an override switch. I used 300 degree high pressure hose and spent one after noon putting it together. It works great! If your transmission is set up right, as mentioned in these other threads, and your temps are remaining under 200 it sould not be an issue for many 1000 of miles (100,000+) If you want the details PM me and ill give you the details. I tow 10000K in the heat (100+ temps) with 30+psi of boost up 6-9 % grades and have not seen 210 yet. Love to help ya. The system ran me about $300 total no more. I works great!

Jon Burnes

 

[jburnes]

I set up a aux cooler with a fan. It comes on at 180 degrees and I have an override switch. I used 300 degree high pressure hose and spent one after noon putting it together. It works great! If your transmission is set up right, as mentioned in these other threads, and your temps are remaining under 200 it sould not be an issue for many 1000 of miles (100,000+) If you want the details PM me and ill give you the details. I tow 10000K in the heat (100+ temps) with 30+psi of boost up 6-9 % grades and have not seen 210 yet. Love to help ya. The system ran me about $300 total no more. I works great!

Jon Burnes