2008 Thomas Saf-T-Liner with Cat C7-210

[cadillackid]

2500 PTS is a standard school bus transmission.. it is a wider ratio gearbox with lower end gears 1-3 for better take off and less stress on the engine / toreque converter during stop N go.. "PTS is Pupil Transport Series". your 4th gear will be 1:1 and your 5th gear will be 0.74:1 overdrive.. that unit is likely 4th gen and could be 6 speed programmed (6th would be 0.64:1)..


the onboard spin-on filters for the 1000 and 2000 series SAE transmissions are identical..


other than the gearing the 1000 and 2000 series are very similar..



the 1000 was initially released as a GMC-only transmission with a GMC bell / tail for the 2500/3500 series pickups with a duramaxx.. the 2000 series was released as the medium duty unit with an SAE3 (or SAE2) bell housing and tail housing..


interestingly enough GM used the SAE series 2000 transmisisons on their medium duty C4500/5500/6500 etc trucks with duramaxx or 8.1 gas.. yet still used the GMC bell 1000 series in their pickups..



its possible someone swapped a 1000HS into a bus ..the HS is a highway series which is kind of wierd for a school bus as it would be geared taller (1000's have a 0.71:1 5th gear and a 0.61:1 6th gear)... seems wierd to me unless the original trans died and they swapped in what they could get from a local shop.. or a local build shop used a 1000 case and installed the guts of a 2500 PTS in it.. (they arent supposed to do that but a non allison dealer might ).. if the yhad actually installed a 1000HS in place of a 2500 PTS, the TCM wouldve complained with ratio error codes and a check-trans light as the gears wouldnt match what the computer thinks they are..

 

[TheForkInTheRoad]

2500 PTS is a standard school bus transmission.. it is a wider ratio gearbox with lower end gears 1-3 for better take off and less stress on the engine / toreque converter during stop N go.. "PTS is Pupil Transport Series". your 4th gear will be 1:1 and your 5th gear will be 0.74:1 overdrive.. that unit is likely 4th gen and could be 6 speed programmed (6th would be 0.64:1)..


the onboard spin-on filters for the 1000 and 2000 series SAE transmissions are identical..


other than the gearing the 1000 and 2000 series are very similar..



the 1000 was initially released as a GMC-only transmission with a GMC bell / tail for the 2500/3500 series pickups with a duramaxx.. the 2000 series was released as the medium duty unit with an SAE3 (or SAE2) bell housing and tail housing..


interestingly enough GM used the SAE series 2000 transmisisons on their medium duty C4500/5500/6500 etc trucks with duramaxx or 8.1 gas.. yet still used the GMC bell 1000 series in their pickups..



its possible someone swapped a 1000HS into a bus ..the HS is a highway series which is kind of wierd for a school bus as it would be geared taller (1000's have a 0.71:1 5th gear and a 0.61:1 6th gear)... seems wierd to me unless the original trans died and they swapped in what they could get from a local shop.. or a local build shop used a 1000 case and installed the guts of a 2500 PTS in it.. (they arent supposed to do that but a non allison dealer might ).. if the yhad actually installed a 1000HS in place of a 2500 PTS, the TCM wouldve complained with ratio error codes and a check-trans light as the gears wouldnt match what the computer thinks they are..

Thanks for the detailed information - very informative for me.

Given I am only going off of what was given to me from Thomas based upon the bus VIN I will need to check the trans itself. Where is the part number /serial numbers normally located on an allison transmission?

Could you possibly comment on two other things regarding this bus.

1. It does not have a shifter on the dash but rather on the floor. Most of the housing is missing. Does this type of shifter confirm or has no bearing on the type of transmission it is?

2. On these trans dip sticks. How much fluid level should show when cold? When hot they should be at full but if at hot and neutral but shows at the fill line how much fluid is typically needed between the two lines? Is that a Gallon or less? I am not sure how much fluid these transmissions take.

I should note that when cold there was no trans fluid showing on the stick but when warmed up ran through gears and checked in neutral the fluid showed per the one photo with fluid on it. The other photo is to show it with no fluid

 

[dbsoundman]

Regarding the question on what filter to buy, I would actually call a Cat dealer with your engine serial number or try finding it on the Cat parts site (https://parts.cat.com/en/ohio) and click "Add equipment", then enter your engine serial number. Select the "truck" version if it gives you an industrial or truck selection.

For my SAP series engine that site gives me the correct 1R-1807 filter when I search "oil filter".