| Author |
Message |
Michael J Ryan (Mjryan) (67.41.243.141)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, December 04, 2003 - 8:27 am: | |
I have a 730 transmission in my AM General coupled to a 8v71t. The transmission shift alright when taking off and heading down the highway, but when in town shifting of the transmission becomes weird. It goes into gear with a big thump, this happens when shifting in and out of high gear around 35-40 mph. Any idea what is happing?
Michael |
Randy4107 (65.73.36.130)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, December 04, 2003 - 9:29 am: | |
I"ve had my 871 with v730 over a year and its always shifted with a thump, I have learned to let of for split second then back on throttle when it shifts, if done right it smooths it out. Randy |
Frank Allen (64.12.96.105)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, December 04, 2003 - 10:38 am: | |
Mine does it too, wish i knew why , whaen i get in traffic i shift to second gear manuely to avoid that problem
Frank Allen
4106 |
Geoff (Geoff) (66.238.120.78)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, December 04, 2003 - 11:27 am: | |
I have an Allison torubleshooting guide.
ROUGH SHIFTING, probable causes:
1. manual selector linkage out of adjustment
2. control valves sticking
3. trimmer valves sticking
4. governor valve misfunctioning
5. modulator valve sticking
6. vacuum modulator valve hose kinked, or leaking
7. mechanical actuator cable kinked, broken, or not properly aligned
8. mechanical actuator malfunctioning
9. engine idle speed too fast (N to D)
10. vacuum modulator failed
Before I looked this up, I though the modulator would be the first thing to look at, now I see it is only one of many things on the list.
--Geoff
'82 RTS CA |
Michael J Ryan (Mjryan) (67.41.243.141)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, December 04, 2003 - 12:59 pm: | |
I forgot to mention, it is air assist, if this makes any difference.
Michael |
smoky (12.222.48.162)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, December 04, 2003 - 11:03 pm: | |
does it only happen on a 3-2 down shift or does it also happen on the 2-1 but not as hard as the 3-2 also is it only on a automatic down shift or will it happen on a manual down shift
Smoky, |
Bill Gerrie (216.185.73.251)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, December 05, 2003 - 12:11 am: | |
Guys
Check with your local Allison dealer. There is a soft shift kit for the V730. It is a certain combination of springs in the valve body. The transit company that I used to work for pioneered the soft shift kit years ago. Maybe Bus Warrior could put his input into this. Bill |
Bill Butler (67.75.227.184)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, December 05, 2003 - 10:27 am: | |
I have had mine for four years now and about
40,000 miles. It always downshifts hard from third to second. I also watch the speed and let off the throttle when it is about to shift down.
It then is a nice soft transition.
Bill Butler, 4905 |
Phil Dumpster (12.230.214.167)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, December 05, 2003 - 11:11 am: | |
If you think the V730 has a rough 3-2 shift you haven't driven a VS-2-8 downshifting out of overdrive. Now that's a lurch. |
Johnny (63.159.120.82)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, December 05, 2003 - 4:42 pm: | |
The 730 at work also lurches on the 3-2 shift...I think it's the converter unlocking. |
madbrit (216.67.216.8)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, December 06, 2003 - 4:55 am: | |
"You rang?"
(Addams family joke, sorry) |
Michael J Ryan (Mjryan) (67.41.243.141)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, December 06, 2003 - 10:57 am: | |
Guy's
It goes into gear with a big thump, this happens when shifting in and out of high gear around 35-40 mph. I have only driven it 200 miles or so. I do not have all the answer you asked. I think it shift hard as stated above into or out of high gear. Bill I will do as you advised.
Michael |
Geoff (Geoff) (66.239.48.59)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, December 06, 2003 - 11:25 am: | |
Michael
Have you noticed if it clunks when you put it into gear from neutral? with your foot on the brake, shift it from drive to reverse a few times and see it it clunks-- if it does it could be a u-joint(s), the slip yoke, of a broken engine or transmission mount. |
Michael J Ryan (Mjryan) (67.41.243.141)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, December 06, 2003 - 11:36 am: | |
Geoff
It does not clunk when shifting from neutral to reverse. After rereading all the post I think it is the nature of the beast. Does a 731 have this problem and if not can it be installed in my bus without a major problem?
Michael |
Smoky (12.222.48.162)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, December 06, 2003 - 1:59 pm: | |
correct me if I wrong because I havent work on a v drive for years but I belive the torque converter locks in 2nd gear and stays on for the 2-3 up shift and also the 3-2 down shift if not at heavy throttle. With the converter locked you will have a harder shift this is not like a car that unlocks the converter during upshifts and down shifts and also uses a duty cycle solenoid so You can hardley feel it something eles you might want check if you think you have a problem is the mechaical modulator first make sure its returning to its full relaxed posistion with no throttle the goenover will still force the downshift based on output shaft speed but if modulator pressure is a little high you will get a bump also when I worked at the Gmc dealer the 3rd clutch was always the one burned out on a v drive in a transit bus because in transit service every time the driver steps on the throttle it down shifts to 2nd then back to 3rd and so on....
so what we would do after a trans repair is bump the throttle pressure up a little to try and save the 3rd clutch however the shift would be harder but we felt this was to better choice to try and extend the life of the 3rd clutch.
Smoky, |