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Transmission cooler replacement order

Thought I would share the email from Rocor for those interested in replacing the transmission cooler. I was going to change radiator and trans fluid but after the Rocor email I think it would be wise to incorporate the cooler at this point.
Rocor email below:
Greg,
 
Thank you for your inquiry.  Hopefully, this cooler is not the original.  Regardless, you would be wise to replace it (given the retarder option on your transmission) to change out the
3-1259B (fixed bundle design) with our PN 5-7099A (floating bundle design) to avoid significant transmission repair cost resulting from a potential fixed bundle failure.
 
The projected service life of the fixed bundle cooler is difficult to predict.  We have heard of our fixed bundle coolers in service for over 10 years in some applications.  It is essentially a function of time vs temperature (fluctuations).  But, with the retarder, the temperatures within the transmission oil cooler can vary dramatically.  Our floating bundle design basically eliminates the potential for thermal fatigue in the cooler tube bundle, as the tube headers are free to float in the cast aluminum shell, which results in no thermal stress/fatigue on the tubes.
 
Our PN 5-7099A (see attached) should be a drop-in replacement for 3-1259B with the same port sizes, etc.
 
Your price for PN 5-7099A is $1,592.00, FOB Burkesville KY 42717-9412.  Ship weight is about 45 lbs for freight estimates.  We currently have this unit in stock.
Although the 5-7099A costs a little more than the 3-1259B, the difference is negligible compared to an $8-10K repair bill.
Greg & Sandy
2001 U270
Build # 5803
Eagle, Idaho

Re: Transmission cooler replacement order

Reply #1 –
Assume it is Rocore: Hydraulic Oil Coolers - Rocore

Any link to the specific PN? BTU comparison to OE?
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Transmission cooler replacement order

Reply #2 –
How many on the forum with retarders have had a $8-10K repair bill because of the cooler going south?

How many have had a failure period?

Re: Transmission cooler replacement order

Reply #3 –
I know one (not on the Forum) whose hydraulic fluid cooler failed. He spend in the 10K range getting all of it fixed as I recall.  The problem was coolant getting into the transmission.  When running the transmission pressures are probably higher then coolant pressure.  Maybe the opposite at rest.

The idea of a newer model that gets rid of the heat stresses makes sense.

The original one perhaps...
Rocore Transmission Cooler for Freightliner 3-1259B DSK-3-1259B | eBay
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Transmission cooler replacement order

Reply #4 –
I would think the cooler longevity would be directly related to how much the retarder is used.

Wife is not happy about this!

Re: Transmission cooler replacement order

Reply #5 –
Ghalid,what model and year is your coach so we know where were at?
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Transmission cooler replacement order

Reply #6 –
My coach is 2001 U270 with Allison MD3000MH_R

The replacement is a Rocor. I was able to get the original part# and manufacture date on the cooler. Dave Wheatley the Shell and Tube Manager with Rocor who I spoke with also called on Foretravel when he worked with Allison as an Application Engineer until 2003. He seemed taken back in the fact that I had the original cooler. He spoke highly of Foretravel! He assured me the replacement PN 5-7099A was a exact replacement to my 3-1259B.
Now the fun begins when all the parts arrive.
Greg & Sandy
2001 U270
Build # 5803
Eagle, Idaho

Re: Transmission cooler replacement order

Reply #7 –
U-tube heat exchangers have been around a very long time. Stress free not so much when Mounted in a horizontal position, if the u tube bundle is truely floating to allow for stress free thermal expansion one end may be unsupported, and tube bundle is a cantilever subject to vibration and vertical shock loads stresses especially in a vehicle. Vertical position is better, but vibration can still  be an issue. At one time cooper diamondback heat exchangers we're available where any leakage can't pollute the other side.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Transmission cooler replacement order

Reply #8 –
Is the  Rokor in our 97 U320 the same unit?
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Transmission cooler replacement order

Reply #9 –
Will crawl under mine,I think the tag is readable.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Transmission cooler replacement order

Reply #10 –
Traveling Man. I had my transmission cooler fail in my coach a 93 U280 no retarder. Repair cost was around  10 or 12 coach bucks as I recall. Stuff has a lifetime. The transmission fluid in our coach's is being cooled by the engine coolant and that is the issue. In an ideal world the systems would be seperate and isolated from each other. Then a failure in either system would not effect the other.  I'm told that is difficult and $$$$$ to do in a rear engine coach. I have often wondered what a coach's " lifetime" is. I'm certain that Foretravels push that "lifetime" envelope.

Roland
1993 U280 4341
2010 Jeep Liberty
The Pied Pipers

Re: Transmission cooler replacement order

Reply #12 –
This is the tag on my replacement cooler for my 2000 u320: 
2000 U320 mid entry  #5688
2006 Jeep Liberty


USMCR retired
SDFD retired
FEMA US&R TF8

Re: Transmission cooler replacement order

Reply #13 –
Sven
Did you replace the hoses going from the cooler to transmission? If so anything special I need to know about hoses or tread seal?

Rocor recommended the 5-7099 because, in his opinion although slightly more expensive it has the floating inner core.
Greg & Sandy
2001 U270
Build # 5803
Eagle, Idaho

Re: Transmission cooler replacement order

Reply #14 –
Hopefully Dave Wheatley's (Rocor) advice on the recommended part# pans out since he worked for Allison for 21 years.
Greg & Sandy
2001 U270
Build # 5803
Eagle, Idaho

Re: Transmission cooler replacement order

Reply #15 –
Quote from: Ghallid –
Sven
Did you replace the hoses going from the cooler to transmission? If so anything special I need to know about hoses or tread seal?

Rocor recommended the 5-7099 because, in his opinion although slightly more expensive it has the floating inner core.
I'm not familiar with the floating inner core, but mine appeared to be in good condition (I cross-cut it) after 18 years of use.  The reason I replaced it was due to heavy rust and I was replacing my radiator for the same reason.  Until I cut it open, I didn't know the condition and replaced it for peace of mind and because of easier access with radiator out.  Had I known the condition and thickness of the wall, I would have restored the outer shell and continued to use it.  I replaced all the hoses connected to the radiator and transmission, which cost over $800 if I recall correctly.  Once I do something, I don't want to have to revisit it (I also rebuilt the fan motors).
2000 U320 mid entry  #5688
2006 Jeep Liberty


USMCR retired
SDFD retired
FEMA US&R TF8

Re: Transmission cooler replacement order

Reply #16 –
Any updates on this?  The original cooler on my 2004 is rusted on the outside but I cleaned it up and the steel still looks sound.  Wondering if any more thoughts on replacing it.
Larry Rubin
2004 U295 38' build 6278
2014 Jeep Cherokee

Re: Transmission cooler replacement order

Reply #17 –
Check his posts out. Has been done long ago.
Richard & Betty Bark & Keiko our Golden Doodle
2003 U320T 3820 PBDS
Build # 6215
MC # 16926
2016 Chevrolet Colorado 4X4 diesel

Re: Transmission cooler replacement order

Reply #18 –
ATF to coolant transmission coolers are always potential trouble. They do make ATF to air coolers for big rig automatics. See: Security Check

P

Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)