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Message |
pat young
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, October 13, 2005 - 4:03 am: | |
Howdy
I am contemplating getting a bus with an automatic, and am wondering if there are any Allisons to avoid.
I believe that the MT 643may be the one to watch out for, but I am not sure. There is one of the early automatics that apparently is worth next to nothing, before Allison went to the super trannies they make now.
I've also heard the six speeds were not good, they often came in midship Crwons.
Frank Rowe of Idaho gave mne some nomemclature for the Allison numbers, so I know (guess) that HT is heavy transmission, AT is automatic, and the numbers also signify something.
Anybody knowledgeable on the pros and cons of the Allison of the 70's and 80's?
Thanks in advance
Patrick Young
1970 Gillig |
Henry R. Bergman, Jr. (Henryofcj)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, October 14, 2005 - 6:41 pm: | |
The older 6 speed Allisions were very very good. The MT (600 torque) was the medium duty and the HT (900 torque) the heavy duty.
They had 6 gears, a lock up clutch and great durability. First gear was a little high and the boxes were quite heavy.
Parts and service for these older Allisions are getting somewhat iffy. Might try Allision direct to seees what is still is available.
The AT (400 torque) was/is a light duty 4 speed without a lockup clutch. Designed for stop and go stuff. We stuffed them into pickup trucks with 453 Detroits.
The MT 640 series had 4 gears, a lockup clutch and Crown used them in their coaches up to 250 hp. Excellent box. Also used in MCI coaches.
The 740 and 750 trannies were designed for HD applications such as some coaches, fire engines and highway trucks. Nearly current stuff.
The new world 6 speeds have 2 overdrives, a lock up clutch, are electronic, expensive, but very cool. Long and heavy. CROWN FOREVER!! |
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