allison performance ???
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09-07-2005, 02:48
Post: #1
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allison performance ???
Hello all I am looking for some help with a allison 643 transmision, I
am very peticular and it is starting to bother me a bit. We are getting some weird shifts on our bird right now, 1st to second is fine and firm, 3rd to 4th is some what troubling on the climb through the rpm range, I get a rpm change 2 times before shifting into 4th gear. It is almost acting like it has 5 gears, is this the torque converter locking up in the 3rd gear range? then shifting to 4th? I guess I think it should just shift 1..2...3....4. I have checked the shift points compared to rpm to speed and they are right on. this trans is the allison MT643 not 640 Mac and Carrie Good 1978 31' FC NA |
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09-07-2005, 02:53
Post: #2
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allison performance ???
Mac,
Sounds like mine. 1, 2, 3, lock-up, 4. David Hollis 78 FC33 Springfield,IL --- In WanderlodgeForum@yahoogroups.com, "mad6mac2000" wrote: > Hello all I am looking for some help with a allison 643 transmision, I > am very peticular and it is starting to bother me a bit. We are getting > some weird shifts on our bird right now, 1st to second is fine and > firm, 3rd to 4th is some what troubling on the climb through the rpm > range, I get a rpm change 2 times before shifting into 4th gear. It is > almost acting like it has 5 gears, is this the torque converter locking > up in the 3rd gear range? then shifting to 4th? I guess I think it > should just shift 1..2...3....4. I have checked the shift points > compared to rpm to speed and they are right on. > > this trans is the allison MT643 not 640 > > Mac and Carrie Good > 1978 31' FC NA |
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09-07-2005, 03:22
Post: #3
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allison performance ???
Converter lock up will result in an RPM drop, like a shift but softer. The
biggest RPM drop will occur at the 3/4 shift. The transmission cable should be totally stroked at wide open throttle. It is imperative that the injector pump lever is totally stroked, then adjust the trans cable stroke. It is very possible to have a misadjusted transmission cable prevent full throttle. The age of your vehicle would suggest the transmission would benefit from operator sensitivity. When accelerating, backing off the throttle or releasing the throttle momentarily can effect an earlier up shift and help keep engine speed down. You wouldn't be happy with the cost of a new transmission. A Wanderlodge is the LAST vehicle to try to save money on a drive line repair. The oil cooler lines are the most vulnerable components, they should be like new. If not, replace them with the appropriate hydraulic lines. Mike Hohnstein ----- Original Message ----- From: mad6mac2000 To: WanderlodgeForum@yahoogroups.com Sent: Wednesday, September 07, 2005 9:48 AM Subject: [WanderlodgeForum] allison performance ??? Hello all I am looking for some help with a allison 643 transmision, I am very peticular and it is starting to bother me a bit. We are getting some weird shifts on our bird right now, 1st to second is fine and firm, 3rd to 4th is some what troubling on the climb through the rpm range, I get a rpm change 2 times before shifting into 4th gear. It is almost acting like it has 5 gears, is this the torque converter locking up in the 3rd gear range? then shifting to 4th? I guess I think it should just shift 1..2...3....4. I have checked the shift points compared to rpm to speed and they are right on. this trans is the allison MT643 not 640 Mac and Carrie Good 1978 31' FC NA ------------------------------------------------------------------------------ YAHOO! GROUPS LINKS a.. Visit your group "WanderlodgeForum" on the web. b.. To unsubscribe from this group, send an email to: WanderlodgeForum-unsubscribe@yahoogroups.com c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. ------------------------------------------------------------------------------ [Non-text portions of this message have been removed] |
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