Previous Thread
Next Thread
Print Thread
Page 29 of 34 1 2 27 28 29 30 31 33 34
Re: Starting to work on the Duster [Re: mopar dave] #2754931
03/23/20 10:28 AM
03/23/20 10:28 AM
Joined: Jan 2003
Posts: 14,479
So. Burlington, Vt.
F
fast68plymouth Offline
I Live Here
fast68plymouth  Offline
I Live Here
F

Joined: Jan 2003
Posts: 14,479
So. Burlington, Vt.
I ran the TA RMVB as well.
I don’t recall the cold fluid shifting worse, but it very well could have.

But, for sure........ if you were at light throttle in 2nd, and let the vehicle speed stabilize for the engine rpm, and allow the converter to lock up....... the 2-3 shift would be pretty harsh and clunky.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: Starting to work on the Duster [Re: fast68plymouth] #2754960
03/23/20 11:16 AM
03/23/20 11:16 AM
Joined: Jan 2003
Posts: 30,947
Oregon
A
AndyF Offline OP
I Win
AndyF  Offline OP
I Win
A

Joined: Jan 2003
Posts: 30,947
Oregon
Yes it could be more of a converter issue than anything. The converter I have is fairly tight and cold fluid might make it tighter. So at light throttle with cold fluid the converter is probably close to locked up. Once things warm up and if I'm in the throttle then the converter is slipping and the shift is much softer. I'll call TA one of these days and talk it over with him. I'm sure he'll be able to fill me in on the details. He will also probably tell me that I'm using the wrong valve body for my application which wouldn't surprise me. Part of the drill when you put a bunch of race car parts on the street.

Re: Starting to work on the Duster [Re: AndyF] #2754966
03/23/20 11:25 AM
03/23/20 11:25 AM
Joined: Jan 2003
Posts: 14,479
So. Burlington, Vt.
F
fast68plymouth Offline
I Live Here
fast68plymouth  Offline
I Live Here
F

Joined: Jan 2003
Posts: 14,479
So. Burlington, Vt.
On that style of VB, since the throttle pressure is fixed(and high), the shift itself is basically the same under most conditions.

The difference in the shift feel is that when the converter isn’t locked up, the clunky shift feel is just absorbed in the converter slip.

The tighter the converter is, the smaller the window is to find a sweet spot to get the shifts in before the converter starts to lock up.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: Starting to work on the Duster [Re: AndyF] #2754968
03/23/20 11:28 AM
03/23/20 11:28 AM
Joined: Jan 2003
Posts: 8,005
Tulsa OK
Bad340fish Offline
master
Bad340fish  Offline
master

Joined: Jan 2003
Posts: 8,005
Tulsa OK
"Positively not for street use" used to come stamped all over the box for the Cheetah RMVB lol. Mine clunks at light throttle slow speeds, but with a 4800 converter once your actually accelerating the tach doesn't even move on the shifts anymore.


68 Barracuda Formula S 340
87 "Chrysler" Conquest
Re: Starting to work on the Duster [Re: AndyF] #2754983
03/23/20 12:12 PM
03/23/20 12:12 PM
Joined: May 2008
Posts: 1,131
Thigh-Gap Junction
@
@#$%&*! Offline
New user name, Same old jerk!
@#$%&*!  Offline
New user name, Same old jerk!
@

Joined: May 2008
Posts: 1,131
Thigh-Gap Junction
Installing a spring on the accumulator piston might just fix it, depending of course on the valve body modifications.

Re: Starting to work on the Duster [Re: @#$%&*!] #2755414
03/24/20 12:09 PM
03/24/20 12:09 PM
Joined: Aug 2003
Posts: 750
Zumbrota,MN
A
als499 Offline
super stock
als499  Offline
super stock
A

Joined: Aug 2003
Posts: 750
Zumbrota,MN
We use the "Positively not for street use" manual valve body in our 24 hour road race car. LOL

fasterfarms (1).jpg
Re: Starting to work on the Duster [Re: als499] #2755417
03/24/20 12:14 PM
03/24/20 12:14 PM
Joined: Jan 2003
Posts: 14,479
So. Burlington, Vt.
F
fast68plymouth Offline
I Live Here
fast68plymouth  Offline
I Live Here
F

Joined: Jan 2003
Posts: 14,479
So. Burlington, Vt.
Wow!!!
There’s a lot going on with that car!!

I like it.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: Starting to work on the Duster [Re: fast68plymouth] #2755425
03/24/20 12:25 PM
03/24/20 12:25 PM
Joined: Jan 2003
Posts: 4,707
Moved to N.E. Tennessee
GomangoCuda Offline
master
GomangoCuda  Offline
master

Joined: Jan 2003
Posts: 4,707
Moved to N.E. Tennessee
It's a lot like a train wreck. I can't stop looking at it. laugh2


In theory, there is no difference between theory and practice. In practice, there is.
Re: Starting to work on the Duster [Re: fast68plymouth] #2760893
04/06/20 08:57 PM
04/06/20 08:57 PM
Joined: Jan 2003
Posts: 30,947
Oregon
A
AndyF Offline OP
I Win
AndyF  Offline OP
I Win
A

Joined: Jan 2003
Posts: 30,947
Oregon
I had a nice chat with Paul Forte today and now I have a better understanding of what is going on. He said I can reduce the harshness of the 2-3 shift by loosening the front band a small amount. He thinks I might have it a hair too tight. He also suggested a full synthetic trans fluid to reduce the shift harshness that I feel when the transmission is cold.

He also said that I shouldn't down shift into first gear unless I'm stopped or moving very slowly. I told him I had downshifted to first for a traffic light but then got back into it when the light turned green. He said if you down shift into first at too high of a speed and then hit the gas hard you can break the sprag. They have had people do that when they use the race valve body on a street car. He builds a pro street valve body that prevents the problem but I don't really want to change valve bodies right now. I don't really need to down shift to first when the car is moving anyway so I just need to stop doing it.

Re: Starting to work on the Duster [Re: AndyF] #2760942
04/06/20 11:20 PM
04/06/20 11:20 PM
Joined: Aug 2006
Posts: 81
langley b.c. canada
D
don miller Offline
member
don miller  Offline
member
D

Joined: Aug 2006
Posts: 81
langley b.c. canada
Andy the type of valve body you have does not apply the band in first. The is no engine braking in first....if you were doing say 30 mph when you clicked it into first and took you foot off the gas the engine would drop down to idle. Back when a lot of us were your and foolish that was our secret advantage when street racing. from a roll. It would act like you had a much loser torque converter. At least until you rolled the sprag over. As Cab would say. Don't ask me how I would know whistling

Re: Starting to work on the Duster [Re: AndyF] #2761916
04/09/20 01:29 PM
04/09/20 01:29 PM
Joined: Jun 2019
Posts: 744
Almost Heaven
B
Bob Stinson Offline
super stock
Bob Stinson  Offline
super stock
B

Joined: Jun 2019
Posts: 744
Almost Heaven
Originally Posted by AndyF
He also said that I shouldn't down shift into first gear unless I'm stopped or moving very slowly. I told him I had downshifted to first for a traffic light but then got back into it when the light turned green. He said if you down shift into first at too high of a speed and then hit the gas hard you can break the sprag. They have had people do that when they use the race valve body on a street car. He builds a pro street valve body that prevents the problem but I don't really want to change valve bodies right now. I don't really need to down shift to first when the car is moving anyway so I just need to stop doing it.


I thought if anyone knew this it would be you. You need a LBA valve body. I bought one to replace the Cheetah in my car if it ever gets back on the road, or to go with it if I ever send it down the road.

I really dig that Duster.


69 road runner A12 ex-racer
71 Duster w/ a 400

Shiny paint causes stress.
Re: Starting to work on the Duster [Re: Bob Stinson] #2761939
04/09/20 02:37 PM
04/09/20 02:37 PM
Joined: Jan 2003
Posts: 30,947
Oregon
A
AndyF Offline OP
I Win
AndyF  Offline OP
I Win
A

Joined: Jan 2003
Posts: 30,947
Oregon
I used a lot of parts that came with the car and the valve body was one of them. Knowing what I know now I might have swapped the valve body or built a different trans. I might still change but I'd have to also change the shifter so the job gets a little more complicated now that everything is together. I'm learning to live with the valve body as is. I just don't shift down to first unless I'm at a dead stop. With the 4.56 gears out back I can slow down to a crawl in 2nd gear and still have enough torque to accelerate. So when I'm tooling around town I just use 2nd a lot.

I took it out today to run some errands. Drove more than 30 miles of stop and go traffic around town and it runs just fine. The coolant temp stays right around 185, oil temp runs around 180 degrees, trans fluid temp stays around 170 degrees. No leaks anywhere, brakes work great. Steering feel is good, it goes around corners just fine but it isn't a road race car.

Re: Starting to work on the Duster [Re: AndyF] #2762186
04/10/20 09:19 AM
04/10/20 09:19 AM
Joined: Jan 2003
Posts: 8,005
Tulsa OK
Bad340fish Offline
master
Bad340fish  Offline
master

Joined: Jan 2003
Posts: 8,005
Tulsa OK
I have driven so long with my old cheetah valve body I am afraid to go LBA. I am bad about dropping it into first as I slow down and just rolling up to the stoplight or whatever. If I ever swap to a low band apply I will probably eat steering wheel a few times until i get retrained.


68 Barracuda Formula S 340
87 "Chrysler" Conquest
Re: Starting to work on the Duster [Re: Bad340fish] #2762279
04/10/20 12:23 PM
04/10/20 12:23 PM
Joined: Jan 2003
Posts: 14,479
So. Burlington, Vt.
F
fast68plymouth Offline
I Live Here
fast68plymouth  Offline
I Live Here
F

Joined: Jan 2003
Posts: 14,479
So. Burlington, Vt.
The thing to keep me in mind is...... with a stock valve body and the shift selector in “drive”, low band apply doesn’t happen.
So, from a stop, the rmvb being shifted 1-2-3 is operating the trans in the same sequence as the stock vb does.

One of my customers had the shift points set where he wanted them with the shifter in “drive”, and raced the car like that for years.
High 11’s in a 3950lb car....... no lba while racing in “D”....... never an issue.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: Starting to work on the Duster [Re: fast68plymouth] #2762326
04/10/20 01:49 PM
04/10/20 01:49 PM
Joined: Aug 2006
Posts: 81
langley b.c. canada
D
don miller Offline
member
don miller  Offline
member
D

Joined: Aug 2006
Posts: 81
langley b.c. canada
The issue isn't from normal upshifting, even if it shifting on the governor. The problem is from backing off then hitting it again the sprag is trying to control the speed of the drum but the drum weight overcomes the sprag pushing the fingers holding the wave springs back. After that happens the drum can over speed engine rpms times whatever first gear ratio the trans has

Re: Starting to work on the Duster [Re: Bad340fish] #2762464
04/10/20 06:56 PM
04/10/20 06:56 PM
Joined: Jan 2003
Posts: 20,149
Park Forest, IL
slantzilla Offline
Too Many Posts
slantzilla  Offline
Too Many Posts

Joined: Jan 2003
Posts: 20,149
Park Forest, IL
Originally Posted by Bad340fish
I have driven so long with my old cheetah valve body I am afraid to go LBA. I am bad about dropping it into first as I slow down and just rolling up to the stoplight or whatever. If I ever swap to a low band apply I will probably eat steering wheel a few times until i get retrained.


It took me one time. hammer fart


"Everybody funny, now you funny too."
Re: Starting to work on the Duster [Re: slantzilla] #2762510
04/10/20 09:56 PM
04/10/20 09:56 PM
Joined: May 2003
Posts: 2,117
Cleveland Ohio
10secGTX Offline
top fuel
10secGTX  Offline
top fuel

Joined: May 2003
Posts: 2,117
Cleveland Ohio
Originally Posted by slantzilla
Originally Posted by Bad340fish
I have driven so long with my old cheetah valve body I am afraid to go LBA. I am bad about dropping it into first as I slow down and just rolling up to the stoplight or whatever. If I ever swap to a low band apply I will probably eat steering wheel a few times until i get retrained.


It took me one time. hammer fart


^^^^^^^^ ME TOO ^^^^^^^

Re: Starting to work on the Duster [Re: Bad340fish] #2762617
04/11/20 10:02 AM
04/11/20 10:02 AM
Joined: May 2008
Posts: 1,131
Thigh-Gap Junction
@
@#$%&*! Offline
New user name, Same old jerk!
@#$%&*!  Offline
New user name, Same old jerk!
@

Joined: May 2008
Posts: 1,131
Thigh-Gap Junction
Originally Posted by Bad340fish
I have driven so long with my old cheetah valve body I am afraid to go LBA. I am bad about dropping it into first as I slow down and just rolling up to the stoplight or whatever. If I ever swap to a low band apply I will probably eat steering wheel a few times until i get retrained.



The factory got it right on this. It could be argued that the purpose of the band apply in Low is to provide engine braking--when needed. It also protects the over-running clutch when pulling a boat out of the water or tugging on a stump. No engine braking in first is normally a good thing. My first car was a police car (383hp B-body) that would down shift to first when coming to a stop (10mph?)--and you could feel it. It drew a lot of comments and I've never had another transmission that would do that. I traded it for a Charger before ever trying to figure out what was different. You could feel that it was ready for you to stab the throttle if you wanted/needed to. It might not take more than a drill bit to tie the rear servo to first gear in Drive-Breakaway, to use the FSM language. If you want spilled drinks in your interior.
twocents

Re: Starting to work on the Duster [Re: @#$%&*!] #2762743
04/11/20 03:45 PM
04/11/20 03:45 PM
Joined: Jan 2003
Posts: 30,947
Oregon
A
AndyF Offline OP
I Win
AndyF  Offline OP
I Win
A

Joined: Jan 2003
Posts: 30,947
Oregon
I'm going to leave the transmission alone for now and just drive it like it has to be driven. Once I get some more miles on it (and some quarter mile passes) I'll know more about what is working and what isn't and then I can make a better decision on next steps.

Right now my focus is on tuning the engine. The left side of the engine is running 1 point leaner than the right side. I swapped the O2 sensors from side to side but that didn't make a difference. So the issue is the engine not the sensors. I think one cylinder on the left side has a bad plug or a bad plug wire so I'm going to change plugs and inspect the wires and then go from there. I could also have a weak injector on the left side but I think it is ignition related not fuel.

Re: Starting to work on the Duster [Re: AndyF] #2773020
05/09/20 10:55 PM
05/09/20 10:55 PM
Joined: Jan 2003
Posts: 30,947
Oregon
A
AndyF Offline OP
I Win
AndyF  Offline OP
I Win
A

Joined: Jan 2003
Posts: 30,947
Oregon
86 degrees today so I spent some time out driving the Duster around. The light was nice so I stopped and shot some pictures. The Duster is running pretty good at the moment. I had a PCV valve go bad and it threw me for a loop for a while since a bad PCV valve creates some problems for an EFI engine. The engine would surge and stutter at random times. I eventually pulled the PCV valve off and that seemed to clear up the problem.

DSC_4142 (Large).JPG
Page 29 of 34 1 2 27 28 29 30 31 33 34






Powered by UBB.threads™ PHP Forum Software 7.7.1