| Author |
Message |
Bob Damm (216.134.164.87)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 10, 2004 - 1:16 pm: | |
The 740 is a four speed right? The MC-9 I am looking at is supposed to have a 740 but the selector is labeled 1 2 3 4 D but doesn't start out in 1st unless manually selected. Is this an overdrive transmission, and if so what is the gear ratio? I've done a google search but can find the answers, but I know someone here will know.
Thanks, Bob |
Randall Hays (69.4.194.104)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 10, 2004 - 2:59 pm: | |
My MCI-8 with a 740 does the same thing, from a stop though it goes thru 5 gear changes. So is it a 740 or a 750 or what? Where do you look to see just what kind of tranny it is that you have? ME TOO with the thanks hehehe |
Jimmci9 (209.240.205.68)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 10, 2004 - 6:24 pm: | |
the 740 starts out in torque convertor, 1st gear... then shifts to lock, 1st gear... 2nd torque convertor, then lock torque convertor... 3rd lock torque convertor... 4th lock torque convertor..depending on shift points. trimmer springs, the phase of the moon. etc, you'll either feel all of the shifts, some of the shifts, or none of the shifts.... |
RJ Long (Rjlong) (66.229.97.200)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 10, 2004 - 8:10 pm: | |
Bob -
More than likely, the transmission in that MC-9 you're looking at is an HT-754CR, which is the five-speed version of the HT-740. Not too many operators ordered them, but they're a sweet transmission as it gives you an extra gear to play with in the mountains. Unfortunately it is not an overdrive model. I'll post the ratios at the bottom of this message.
The four-speed HT-740's gear selector reads 1-2-3-D-N-R. With the 740, starting in Drive, you will feel five "upshifts", four of which are actual shifts and one is the torque converter locking up. IIRC, the sequence is 1C-2C-2LU-3LU-4LU.
As you've discovered, the HT-754CR's gear selector reads 1-2-3-4-D-N-R. With this tranny, you should feel six "upshifts" when starting in Drive. The sequence is 1C-2C-2LU-3LU-4LU-5LU. If you only feel five upshifts, then the transmission has the optional 2nd gear start.
To determine exactly which transmission it is, you'll have to get the coach either over a pit or safely blocked up in order to get underneath. There should be an ID plate on the gearbox, driver's side, I believe. (Someone correct me here if I'm wrong about the ID plate's location.)
The gear ratios for the two transmissions are:
HT-740 series:
First = 3.692
Second = 2.021
Third = 1.383
Fourth = 1.000
Reverse = 6.035
HT-754CR (Close Ratio):
First = 3.692
Second = 2.002
Third = 1.583
Fourth = 1.253
Fifth = 1.000
Reverse = 9.648
Bob - if that MC-9 is in overall good shape, it might worth a few extra dollars for the five-speed automatic. West Coast or East Coast bus??
HTH,
RJ
PD4106-2784
Fresno CA |
Gary Carter (68.25.1.159)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 11, 2004 - 12:00 am: | |
There are a few versions of the 740 that shifts 1C 1L 2C 2L 3C 3L 4C 4L. |
Bob Damm (216.134.163.46)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 11, 2004 - 1:46 pm: | |
Thanks for the info RJ Long. I was told by the head of maintenance that this bus will not start in first unless you manualy select it. I remember asking if it was a five speed because I saw 1234D.
I wanted to know if it was overdrive so I can figure RPM vs MPH. It has a 3.73 diff. and 8v71 so with the tires it will have, 488 REV. per mile, I figure it should do about 68 or 69 at 2100 RPM.
This is an '81, nice and clean, a Seattle bus and has spent some time in Alaska as well.
I would like to use the sink in the restroom but every commercial bus operator I've talked to said they don't us them and the plumbing seems to be a mystery to them other than the tank is behind the mirror. Can anyone shed some light on hot the plumbing is supposed to work??
Thanks,
Bob |
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