Four Speed Questions (AT 542)

[Damon92]

I just bought 1992 Damon Challenger this month. It is a 32' DP with 5.9 190 HP Cummins and an Allison AT 542 transmission. I just bought new radiator and transmission cooler from Hayden that I am planning to install next week. While Im at it I wanted to change fluid to Transynd since I don't know the history. Is this as simple as draining/adding with new filters? The place that sold me the cooler wants $200 for 5 gallons. Does this sound right? I also want to put a temp gauge on Transmission but wondering what kind and if theres a plug already to screw bung into. (Ive heard there was) Do I just need a universal electronic Auto Meter? the one Im looking at only reads to 250. What is the safe operating temp for this trans? I will be pulling a trailer (6x16) that weighs 7,000 lbs. Since Im asking a lot from this transmission I want to be sure to keep it cool. It has 76K on it. I have found answers similar to my question but not specifically for unit.
Thank you

[jauguston]

The best location for the fluid temp sender is at the fluid out to cooler fitting that is on top on the right front corner of the transmission case. Using synthetic fluid the maximum SAFE temperature is 300 degrees. I had that transmission in my last coach and used a Isspro electric gauge that went to I think 320-350. I could exceed 300 degrees using the exhaust brake I installed along with a BD low stall speed torque converter if I didn't watch it.

Jim

[Damon92]

Thank you for response I will adding a gauge. I don't think Im gonna have the motor turned up. Even tho its a 190hp I am pleased with how it pulls my trailer.
Thanks again for info

[jauguston]

If you find you want a bit more power a swap to 275RV injectors will give you a nice boost. I did that and had the ECM reprogrammed to the 275 RV map. If your motor does not have a two piece exhaust manifold keep a eye on it. When you work them hard the one piece manifold tends to crack. Cummins required I install a two piece manifold before they would remap the ECM.

Jim

[BFlinn181]

I have the same transmission, my 5.9 is rated at 210 hp. The trannie holds 11 quarts of fluid. As I understand it, since the torque converter doesn't drain when you do a fluid change, the amount of old fluid trapped in that then mixes with the new and it isn't considered a full change over to Transynd until after the second change. A 542 doesn't have a lock up converter, so don't plan on installing an exhaust brake unless you do as jauguston did and install a BD low stall speed torque converter.

Also, because of the 542 torque limits, you can only tweak the engine to about 230 hp before it would be exceeding the limits. I've read of some people who have modified the 5.9 cummins up to 275 without damage to to the 542. (so far?) I had no problems from Ohio to Seattle and back except for some minor high engine temps. I believe it was a dirty radiator. The slobber tube from the engine blows oil back onto the radiator and blocks it. I've given it a though cleaning and exterior flush and hope to find out if it's O.K. on a trip to Maine over the next few weeks.

I added an Isspro digital exhaust gas pyro and a transmission temp digital gauge because they are one of the few that you can extend the length of the run between sensor and gauge by just splicing in 18 gauge wire. (I checked with a few gauge makers and Isspro was the only one that O.K.ed it.)

[BFlinn181]

I believe the 12 v 5.9 Cummins is all mechanical, it doesn't have a programmable ECM.

[jauguston]

181,


When I uprated my '99 ISB 210 to 275RV specs I called Allison to see if I was going to have problems with my AT542 at 275 HP. The Tech Support guy said If I converted to synthetic fluid and monitored fluid temperature at the fluid out to cooler location and did not exceed 300 degrees I would be fine. I had no trouble.

I also added a Isspro pyrometer and boost gauge. I called Isspro and asked if the 35' of 18ga wire added would effect the accuracy. The engineer I talked to did a quick calculation and said it would make the gauge read approximately .3 degrees high-no problem.

Jim

[BFlinn181]

Originally Posted by jauguston

181,

His 1992 model coach will have either a first generation or possibly second generation ISB 24 valve engine. The ISB first gen motor came out in 1998.5 and was built until 2002 so he likely has a chassis built in 2001.

Does it have a Flux Capacitor so the chassis built in 2001 could go back in time 9 years and have a 1992 body put on it? ---just sayin'

[jauguston]

Brain Far* (-:

I was seeing 1992 and thinking 2002. OOPS!

Jim

[Damon92]

Since its a 1992 Mechanical 5.9...wouldnt the best way to add power be thru turning up the injected pump? Mine says its a Bosch. There are a couple of high performance diesel shops here in Nashville that Im sure could do it but how much would I be up against for a job like this? I can do gauges/fluids myself.
Thanks again
Brandon

[BFlinn181]

I believe new injectors will be the best bang for the buck on a 1st generation 5.9 12 valve. Better intake and exhaust can also help, but it gets expensive. Always be aware of the limitations of the AT 542. Check here for info and parts ideas. Dodge Diesel Performance | Dodge Transmissions | Pure Diesel Power

[jauguston]

I don't know exactly what they do but on a 12v 5.9 they talk about a plate on the pump that gets changed to add power.Supposedly easy and inexpensive. Find a local diesel performance shop in your area. They will have the lowdown on what you can do.

Jim

[BFlinn181]

A '92 is a First generation 59 12 v. I don't think it has an adjustable Torque/Cam/Fuel Plate. That is a part that can be bought for the Second generation 5.9, built from '94 to '98.5. Check the link in post 11 for parts available.