Broke this transmission sensor

Scott & Heather · April 08, 2020, 09:41:28 PM

Not sure how but I managed to break what I think is a temp sensor on my Allison HT748. Anyone have any clue where I could order one?

lostagain · April 09, 2020, 06:39:52 AM

Detroit Allison dealer.

luvrbus · April 09, 2020, 07:07:02 AM

Most of the sensors and sending units on the Allison 748 are the same as the GM 4L60-E transmission and are available through Napa and others,even the shifting solenoids are the same

DoubleEagle · April 09, 2020, 07:09:20 AM

The 700 series is considered obsolete by Allison. One other source is Transtar Industries, Inc. transtar1.com. Your part is probably a temperature sensor or probe. Cliff's suggestion is probably the best tip.

Scott & Heather · April 09, 2020, 07:45:49 PM

Done did find a shop that has a guy that knows these older Allison's well. Curtis Martin of Martin Truck in Maryland gave me a 30 minute tutorial on my 748 today. Was eye opening. That is indeed a temp sensor that is not needed for trans operation. But I did order a new sensor and gauge from him today. I'll also be reactivating my disabled retarder now that I know how it works. Good stuff.

sledhead · April 11, 2020, 05:49:56 AM

Curtis was a great help for me when I had leids rebuild my 6v92ta and it was leids that gave me his name and # as well . great guy

are you guys up and running ?

dave

luvrbus · April 11, 2020, 07:24:06 AM

The 748 is the same transmission as the old 740 just electronically controlled with all the upgrades it is a good transmission,the 755 CR (5 speed) is a better transmission for a bus IMO

Scott & Heather · April 13, 2020, 05:18:00 PM

Dave not yet. Curtis sent me a new sensor and gauge. I have some retarder wiring to still fix. Then I can slide the engine back in.

Brian Diehl · April 13, 2020, 07:39:11 PM

Quote from: luvrbus on April 11, 2020, 07:24:06 AM
The 748 is the same transmission as the old 740 just electronically controlled with all the upgrades it is a good transmission,the 755 CR (5 speed) is a better transmission for a bus IMO

I really liked the 755 originally in my bus. It was just about perfect for the engine except for some steeper hill climbs. Transmission was even better once I got it configured for torque converter lockup in any gear to make coming down steep slow grades less hair-raising!