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Damon92 · 07-31-2012, 06:29 PM

I just had the radiator rebuilt on my 32' 1992 Damon Challenger with 5.9 Cummins/Allison 4 spd on an Oshgosh Chassis. Everything seems to be operating as it should. However, I intend to do a lot of interstate driving pulling my 6x14 enclosed trailer. I was wanting to get some opinions on adding a second trans cooler. The one from the factory is LARGE and flushed and should be adequate, but from what I have read on here the weak link on my rig is the AT 542 and as affordable as an aux cooler would be ($100) I am thinking about it. Also if you DID, would the correct fluid sequence be: tranny, stock cooler, aux cooler, tranny?
Thanks! I have learned so much from this site!
Brandon

JimM68 · 07-31-2012, 06:34 PM

what temp did your trans run before?

for a hundred, I would just do it.
is your factory cooler built into the radiator?
if it is, I would lose it completely if you have room. install a big aftermarket cooler with it's own thermostatically controlled fan, bypassing the factory cooler completely.

Damon Outlaw · 07-31-2012, 06:37 PM

What transmission fluid are you running now?

You may be able to upgrade to a chemical synthetic fluid which would lower temperatures, provide more protection at higher temperatures and eliminate the need for an additional cooler.

Damon92 · 07-31-2012, 06:41 PM

I am not sure. I bought the coach a few weeks ago and haven't installed a gauge yet. I am going to change fluid this weekend.

Damon Outlaw · 07-31-2012, 07:08 PM

What specs and fluid are you changing to? Make sure it is a Chemical synthetic.

Damon92 · 07-31-2012, 08:26 PM

I am planning to put many miles on coach so service will be very regular. In your opinion is the synthetic going to make that much difference? Enough to justify extra cost? The aux cooler Vs. synthetic is almost a wash isn't it? Does anyone have info on towing with my Allison 4spd?

Damon Outlaw · 07-31-2012, 08:32 PM

You might consider having the fluid analyzed to see what kind is in it, how much longer it may be used, and how the transmission is wearing.

Yes, Chemical synthetic is worth it over conventional. It will last longer requiring fewer changes, better protection and improve mpg. Less expensive in the long run.

George Schweikle · 08-01-2012, 05:34 AM

Hi Damon92,

The correct sequence is to buy a transmission temperature gauge first. Without knowledge of tranny temperature, you are just whistling in the dark. BTW, I usually tow a car trailer and always install a second cooler. Almost 375,000 miles on gas RV's since 1977, always with a second cooler and never a transmission problem.

Quote:

Originally Posted by Damon92

I just had the radiator rebuilt on my 32' 1992 Damon Challenger with 5.9 Cummins/Allison 4 spd on an Oshgosh Chassis. Everything seems to be operating as it should. However, I intend to do a lot of interstate driving pulling my 6x14 enclosed trailer. I was wanting to get some opinions on adding a second trans cooler. The one from the factory is LARGE and flushed and should be adequate, but from what I have read on here the weak link on my rig is the AT 542 and as affordable as an aux cooler would be ($100) I am thinking about it. Also if you DID, would the correct fluid sequence be: tranny, stock cooler, aux cooler, tranny?
Thanks! I have learned so much from this site!
Brandon

Damon Outlaw · 08-01-2012, 07:42 AM

Quote:

Originally Posted by George Schweikle

Hi Damon92,

The correct sequence is to buy a transmission temperature gauge first. Without knowledge of tranny temperature, you are just whistling in the dark.

Make sure to get a digital readout and maybe one for the differential as well. Mine is a boring gauge and I've never seen it go beyond mid range and includes over 100F and Rocky Mountain driving with a full garage without an extra cooler.

WeatherTodd · 08-01-2012, 07:53 AM

you could add it anywhere just need to have the proper fittings and be in direct flow of air for best efficiency

jauguston · 08-01-2012, 03:09 PM

Our last coach was a similar power train with a early ('99) ISB 5.9 Cummins and a AT 542.

My suggestion is number one install a transmission fluid temperature gauge in the line out to the cooler. There is a elbow fitting coming out of the top right front corner of the transmission case with a hose connected to it. That is fluid out to cooler. There may be a Tee there instead of a El with a temp sender already there for a factory transmission temp gauge Mine did and I removed it and installed a Isspro transmission gauge sender in its place.

Second replace the transmission fluid with synthetic fluid that has on the label "Meets TES-295 spec. Castrol Syntech is the most common. Amsoil does not meet the spec. Truck shop parts departments have Fleetgard that does.

With TES-295 spec synthetic fluid fluid temperatures up to 300 degrees measured at the fluid out location is safe verified by Allison Tech Support.

You will find the bad thing about a AT-542 is it does not have a lockup torque converter so when going down hill you will get nearly no engine braking meaning you have to be quite careful to not overheat your brakes. A exhaust brake will do no good unless you replace the torque converter with a low stall speed torque converter from B-D. That is what I did. Using the exhaust brake I still had to watch the fluid temperature as it would easily go over 300 if I didn't watch it on a long down hill.

I would wait to add another cooler until you see what temperatures you see.

Jim

Damon Outlaw · 08-01-2012, 03:27 PM

Quote:

Originally Posted by jauguston

Second replace the transmission fluid with synthetic fluid that has on the label "Meets TES-295 spec. Castrol Syntech is the most common. Amsoil does not meet the spec.

Amsoil lists the TES-295 spec on the label and at a lower price and a better warranty. "AMSOIL Torque-Drive is recommended as a direct replacement for TranSynd Synthetic ATF in heavy duty, on- and off-highway automatic transmissions manufactured by Allison,® General Motors,® Ford,® Voith® and ZF® or wherever the standards TES-295, TES-389, C-4, Dexron® III, Mercon,® Voith 55.6336.XX (G-1363) or ZF® TE-ML 14C are specified. Examples of operations that benefit from using AMSOIL Torque-Drive include municipal or transit buses, motor coaches, garbage haulers, motor homes, delivery vans, emergency vehicles, school buses, dump trucks,
utility vehicles, cement trucks, line haul trucks and tow trucks."

BFlinn181 · 08-01-2012, 03:51 PM

Quote:

Originally Posted by Damon Outlaw

Amsoil lists the TES-295 spec on the label and at a lower price and a better warranty. "AMSOIL Torque-Drive is recommended as a direct replacement for TranSynd Synthetic ATF in heavy duty, on- and off-highway automatic transmissions manufactured by Allison,® General Motors,® Ford,® Voith® and ZF® or wherever the standards TES-295, TES-389, C-4, Dexron® III, Mercon,® Voith 55.6336.XX (G-1363) or ZF® TE-ML 14C are specified. Examples of operations that benefit from using AMSOIL Torque-Drive include municipal or transit buses, motor coaches, garbage haulers, motor homes, delivery vans, emergency vehicles, school buses, dump trucks,
utility vehicles, cement trucks, line haul trucks and tow trucks."

Here we go again. Amsoil has NEVER submitted its fluids to Allison for approval. Amsoil says it meets the TES-295 spec, but they have not had it independently tested and the results submitted to Allison or any other major manufacturer of autos or trucks. It might work OK, but some reports of leaking transmission seals have been reported with its use. Stick to an APPROVED fluid for your RV.

jauguston · 08-01-2012, 04:46 PM

Our resident Amsoil peddler says that their synthetic transmission fluid meets TES-295. I just Googled Amsoil synthetic transmission fluid. Guess what - Their web site does NOT list TES-295 as a fluid theirs meets. What say you peddler?

Jim