2nd Gen diesel trucks come with (2) Group 27 top post batteries from OEM. My 27’s at the time were 750 CCA.
They work fine for most of our truck’s service life but if your like me and have a few extra electrical loads then moving up to commercial Group 31’s is an ideal modification.
There is an article here about modifying the plastic OEM trays to accept 31’s but in my case after 25 years and weathering & fear of cracking I just wanted a new hassle free setup.
The only company (so far) offering this is LRB Speed. They made them for the early 2nd gens (94-98.5) and they weren’t tested in the later ones. I rolled the dice and found they work fine with only minimum modification.
They come unassembled so just follow the directions and rivet them together. They make them to accommodate the factory temp sensor & cruise servo for the L/H tray. I don’t have a cruise servo so this didn’t apply to me, the temp sensor bracket was a perfect fit for the sensor.
The only mod I had to do was move the horns somewhere else as the R/H tray will contact them. So I moved them to a bracket that supports my Webasto coolant heater and simply extended & secured the factory wiring harness. The bottom of each tray mounts through the holes in the bottom of the fender. I drilled the tray holes bigger and installed 5/16” rivnuts instead of the smaller M8 ones they come with (for rigidity).
I installed two standard/flooded 925 CCA top stud batteries with 190 minute reserve capacity. I put lug terminals on them so as to not have to modify my battery cables.
Main reason I did this is my Webasto was starting to draw the 27’s down enough that I would get a no flame fault and it wouldn’t run in the cold mornings before I went to work.
I run a Nations 180A alternator and with the W-T mod and upgraded battery cables completed a few years earlier I feel I have a very reliable setup now.
2nd Gen diesel trucks come with (2) Group 27 top post batteries from OEM. My 27’s at the time were 750 CCA.
They work fine for most of our truck’s service life but if your like me and have a few extra electrical loads then moving up to commercial Group 31’s is an ideal modification.
There is an article here about modifying the plastic OEM trays to accept 31’s but in my case after 25 years and weathering & fear of cracking I just wanted a new hassle free setup.
The only company (so far) offering this is LRB Speed. They made them for the early 2nd gens (94-98.5) and they weren’t tested in the later ones. I rolled the dice and found they work fine with only minimum modification.
They come unassembled so just follow the directions and rivet them together. They make them to accommodate the factory temp sensor & cruise servo for the L/H tray. I don’t have a cruise servo so this didn’t apply to me, the temp sensor bracket was a perfect fit for the sensor.
The only mod I had to do was move the horns somewhere else as the R/H tray will contact them. So I moved them to a bracket that supports my Webasto coolant heater and simply extended & secured the factory wiring harness. The bottom of each tray mounts through the holes in the bottom of the fender. I drilled the tray holes bigger and installed 5/16” rivnuts instead of the smaller M8 ones they come with (for rigidity).
I installed two standard/flooded 925 CCA top stud batteries with 190 minute reserve capacity. I put lug terminals on them so as to not have to modify my battery cables.
Main reason I did this is my Webasto was starting to draw the 27’s down enough that I would get a no flame fault and it wouldn’t run in the cold mornings before I went to work.
I run a Nations 180A alternator and with the W-T mod and upgraded battery cables completed a few years earlier I feel I have a very reliable setup now.
View full Cummins article