Moparts
can an auto trans shift "too hard", causing damage?
Posted By: cal_gecko
can an auto trans shift "too hard", causing damage? - 02/16/14 06:07 PM
Just curious.. with the stuff I've got in my 904, it shifts REALLY hard.. almost violently ..
Griner reverse manual VB with low band apply
Red clutches with Kolene Steels
Low 1st gear
Kevlar bands
mild torque converter (I think around 2800 rpm)
The engine is a mild 360 ..
When it shifts, it knocks you back in your seat.. depending on RPMs and throttle, it has no problem breaking the tires loose going from 1-2 and will sometimes do it going from 2-3 ...
So my question is, .. "is there any risk of causing damage to other components of the drivetrain by having a shift that is this 'hard'?"
Rear end is recently completely rebuilt .. new Eaton True-Track, new ring/pinion, bearings, etc..
What would any potential 'weak point' be that I should consider beefing up for the way this thing shifts?
Posted By: jcc
Re: can an auto trans shift "too hard", causing damage? - 02/16/14 07:39 PM
Weak point my guess in your case would be DS/U joints, but the hard shifting in a street car would get old fast for me.
Posted By: cal_gecko
Re: can an auto trans shift "too hard", causing damage? - 02/16/14 08:28 PM
it's not bad if I want to cruise, I can start in 2nd gear and quickly shift to 3rd before RPM's get up too high, it's not too bad.. however, that doesn't seem to happen too often, LOL..
could be a contributing factor to me getting 8mpg.. just a guess..
Posted By: Cab_Burge
Re: can an auto trans shift "too hard", causing damage? - 02/16/14 09:24 PM
Posted By: cal_gecko
Re: can an auto trans shift "too hard", causing damage? - 02/16/14 09:45 PM
Quote:
Harsh shifts like your having are usually caused by two gears being engaged, overap, at the same time 
Check your shifter adjustment 
I make sure the button on the shifter cable will slide easily into the shifter arm in nuetral, 1st, 2nd and 3rd gear with no visible movement of the shifter arm or button 
If either moves adjust the parts until they don't
I recently double checked my adjustments and the trans doesn't shift any different, so I'm guessing they're where they should have been.. but I'll double check the cable going to the shift linkage to ensure that when it goes into gear, it's not close to another gear.. I'm using a B&M Quicksilver shifter, if that matters.. I doubt it though.
Posted By: 340SHORTY
Re: can an auto trans shift "too hard", causing damage? - 02/16/14 10:09 PM
race tranny in a street car..
Posted By: cal_gecko
Re: can an auto trans shift "too hard", causing damage? - 02/16/14 10:11 PM
Quote:
race tranny in a street car..
That's what I get for asking John Cope for transmission advice, LOL!!
Posted By: mcmopars
Re: can an auto trans shift "too hard", causing damage? - 02/16/14 11:45 PM
Quote:
Just curious.. with the stuff I've got in my 904, it shifts REALLY hard.. almost violently ..
Griner reverse manual VB with low band apply
Red clutches with Kolene Steels
Low 1st gear
Kevlar bands
mild torque converter (I think around 2800 rpm)
The engine is a mild 360 ..
When it shifts, it knocks you back in your seat.. depending on RPMs and throttle, it has no problem breaking the tires loose going from 1-2 and will sometimes do it going from 2-3 ...
So my question is, .. "is there any risk of causing damage to other components of the drivetrain by having a shift that is this 'hard'?"
Rear end is recently completely rebuilt .. new Eaton True-Track, new ring/pinion, bearings, etc..
What would any potential 'weak point' be that I should consider beefing up for the way this thing shifts?
awsome 360 theat will bust em loose on 2-3 shift.my cope built mvb trans shifts very hard at cruising,to the point i dont like it ,never broke anything yet,full throttle is very firm.its street driven,if i had to do it again i would have him build a auto shifting trans.just make sure you have the good u-joints,which im sure you do.
Posted By: John_Kunkel
Re: can an auto trans shift "too hard", causing damage? - 02/17/14 12:25 AM
RMVB's run the line pressure wide open all the time, this results in WOT shifts even at low speeds.
The lighter the car, the lower the axle ratio and the tighter the converter, the more you will feel it in the "buttmeter"....and, yes, it's hard on parts.
Posted By: cal_gecko
Re: can an auto trans shift "too hard", causing damage? - 02/17/14 12:54 AM
Quote:
RMVB's run the line pressure wide open all the time, this results in WOT shifts even at low speeds.
The lighter the car, the lower the axle ratio and the tighter the converter, the more you will feel it in the "buttmeter"....and, yes, it's hard on parts.
So, being that the Dart is not a super-heavy car, I have 3.55 gears, and a moderate torque converter.. those are some of the reasons it's so noticeable.. makes sense!
Posted By: 80fbody
Re: can an auto trans shift "too hard", causing damage? - 02/17/14 01:10 AM
John, is the line pressure adjustable on the Griner? Wondering if a pressure check / lowering & possibly loosening the front band a little would make a difference without significant wear increase on the band/clutches.
Posted By: Coronet-R/T-Rag
Re: can an auto trans shift "too hard", causing damage? - 02/18/14 05:24 AM
Make sure your rear lug nuts are tight. Don't ask me why or I will be forced to tell you.
Posted By: floridian
Re: can an auto trans shift "too hard", causing damage? - 02/18/14 02:31 PM
Quote:
race tranny in a street car..
I had a lowered 2WD stepside chevy with a 454/ turbo 400 that shifted like that.. Kinda fun but grew old fast... or maybe I just got old
Posted By: 98 SNAKE EATER
Re: can an auto trans shift "too hard", causing damage? - 02/18/14 02:45 PM
Quote:
Harsh shifts like your having are usually caused by two gears being engaged, overap, at the same time Check your shifter adjustment I make sure the button on the shifter cable will slide easily into the shifter arm in nuetral, 1st, 2nd and 3rd gear with no visible movement of the shifter arm or button If either moves adjust the parts until they don't
Won't make a difference in his case running a MVB
There's full line pressure for each shift, so it will shift hard regardless.
My 69 RR with a Cheetah RMVB shifts is the same way and breaks the tires loose very easily in any gear, so I usually up shift at a low RPM and just let the torque of the motor take care of things while cruising
Big soft sticky tires makes a huge difference though.
https://www.youtube.com/watch?v=rT5f2z7PTQc
It's almost buttery smooth when I run my MT Sportsman Pros
As for damage, U-Joints and seat backs come to mind
Posted By: Diplomat360
Re: can an auto trans shift "too hard", causing damage? - 02/18/14 03:44 PM
I have a home built 727 here, the line pressure is adjusted to the MAX, pretty much too high, no doubt about it...the result is nearly what you describe, although I have often wondered if I get a slight bind between the 1st and 2nd gear because the shift is extremely harsh. 2nd to 3rd is softer...
Posted By: bonefish
Re: can an auto trans shift "too hard", causing damage? - 02/18/14 04:03 PM
i,ve been running my Cope tranny in my street car for the last 8,000 miles the only damage so far is my back teeth are startin come loose.
Posted By: slantzilla
Re: can an auto trans shift "too hard", causing damage? - 02/18/14 06:49 PM
It's easy to tell a hard shift from overlap. If you have overlap the car will drop the nose on the shift, a clean shift will keep it up.
You can have overlap no matter what valve body you have.
Posted By: JohnRR
Re: can an auto trans shift "too hard", causing damage? - 02/18/14 10:30 PM
Quote:
I have a home built 727 here, the line pressure is adjusted to the MAX, pretty much too high, no doubt about it...the result is nearly what you describe, although I have often wondered if I get a slight bind between the 1st and 2nd gear because the shift is extremely harsh. 2nd to 3rd is softer...
1st is the rear clutch engaged, it is engaged in ALL forward gears.
There is no way to have a BIND between 1st and second because all that is happening on the 1-2 shift is the front band is stopping the front drum from spinning...
unless you have a manual shift only valve body that has low band apply and the front band is stopping the front drum completely before the rear band releases ...
Posted By: Diplomat360
Re: can an auto trans shift "too hard", causing damage? - 02/18/14 10:45 PM
Quote:
1st is the rear clutch engaged, it is engaged in ALL forward gears.
There is no way to have a BIND between 1st and second because all that is happening on the 1-2 shift is the front band is stopping the front drum from spinning...
unless you have a manual shift only valve body that has low band apply and the front band is stopping the front drum completely before the rear band releases ...
Ahh...very good information...well, this is a regular automatic valve body, the trans has been rebuilt with a SMR rebuild kit, fitted with a shift-kit, your typical 'shift improver' stuff and a few parts/add-ons that were suggested to me at that time like the 5.0 lever, accumulator blocker rod (keep in mind, this is a good 15 yrs ago...at least...). The car only has 1k miles since I finally got that thing on the road last year...LOL!
Specifically, the MP P4349469 kit (727 Accumulator and Piston Blocker Rod kit) states the following (which is where I got my MAX line pressure setup from):
=== START ===
Step3: Adjust line pressure to maximum with Allen head adjustment screw. Rotate counterclockwise to compress the spring until almost all available threads are used. Allow enough threads to completely egage adjustment bracket.
=== STOP ===
Other then the harsh but very quick gear shift (which I do not mind, even though it's jolting) I am happy with the trans. The 2nd to 3rd gear shift is much softer though...I think this is something that can be tuned though...need to do a little more research/reading.
Posted By: RSNOMO
Re: can an auto trans shift "too hard", causing damage? - 02/18/14 10:51 PM
That trans is WAY too radical for what you're doing...
And it's gonna find the weakest point...
Zing..
Posted By: JohnRR
Re: can an auto trans shift "too hard", causing damage? - 02/19/14 12:26 AM
Quote:
That trans is WAY too radical for what you're doing...
And it's gonna find the weakest point...
Zing..
Lose the 5.0 lever and the accumulator blocker rod. Put a 3.8 lever in it , 5.0 is a HEMI part that helped apply more leverage on the wide hemi band , it may apply quicker but it releases slower ...
or does it apply slower and release faster ??? 
Posted By: cal_gecko
Re: can an auto trans shift "too hard", causing damage? - 02/19/14 01:02 AM
Quote:
Quote:
That trans is WAY too radical for what you're doing...
And it's gonna find the weakest point...
Zing..
Lose the 5.0 lever and the accumulator blocker rod. Put a 3.8 lever in it , 5.0 is a HEMI part that helped apply more leverage on the wide hemi band , it may apply quicker but it releases slower ...
or does it apply slower and release faster ???
HUH???
Posted By: mcmopars
Re: can an auto trans shift "too hard", causing damage? - 02/19/14 01:16 AM
in your first statement you said it is a griener rpmvb,now you state its and automatic????
Posted By: mcmopars
Re: can an auto trans shift "too hard", causing damage? - 02/19/14 01:18 AM
Quote:
in your first statement you said it is a griener rpmvb,now you state its and automatic????
sorry my bad
Posted By: barracuda7199
Re: can an auto trans shift "too hard", causing damage? - 02/19/14 01:41 AM
Quote:
Quote:
That trans is WAY too radical for what you're doing...
And it's gonna find the weakest point...
Zing..
Lose the 5.0 lever and the accumulator blocker rod. Put a 3.8 lever in it , 5.0 is a HEMI part that helped apply more leverage on the wide hemi band , it may apply quicker but it releases slower ...
or does it apply slower and release faster ???
why lose the blocker rod? what about the 4.2 lever?
Posted By: RSNOMO
Re: can an auto trans shift "too hard", causing damage? - 02/19/14 03:34 AM
Quote:
HUH???
Blocking the accumulator firms-up the shift...
'5.0' lever takes the kick-down shift point upstairs...
Posted By: Diplomat360
Re: can an auto trans shift "too hard", causing damage? - 02/19/14 04:35 AM
Quote:
Quote:
Quote:
That trans is WAY too radical for what you're doing...
And it's gonna find the weakest point...
Zing..
Lose the 5.0 lever and the accumulator blocker rod. Put a 3.8 lever in it , 5.0 is a HEMI part that helped apply more leverage on the wide hemi band , it may apply quicker but it releases slower ...
or does it apply slower and release faster ???
HUH???
Sorr cal_geco, that's my fault...I responded to your original post and JohnRR responded to one of my posts which started a sub-conversation...
Posted By: JohnRR
Re: can an auto trans shift "too hard", causing damage? - 02/20/14 03:26 PM
Quote:
Quote:
Quote:
That trans is WAY too radical for what you're doing...
And it's gonna find the weakest point...
Zing..
Lose the 5.0 lever and the accumulator blocker rod. Put a 3.8 lever in it , 5.0 is a HEMI part that helped apply more leverage on the wide hemi band , it may apply quicker but it releases slower ...
or does it apply slower and release faster ???
why lose the blocker rod? what about the 4.2 lever?
3.8 or 4.2 ...
Posted By: GTX MATT
Re: can an auto trans shift "too hard", causing damage? - 02/20/14 03:52 PM
The 5.0 lever on a regular non-hemi band usually causes excessive shift overlap and can actually cause the output shaft to lock up in between shifts. If you want to verify put the car on a lift, have someone start in low and bring it up to speed. Watch the tires as they select second. If you see the wheels stop in between shifts you have too much overlap.
Alot of times you need to install a restrictor plug on one of the ports (not sure which) to delay the apply to eliminate this with the 5.0 lever. I will say though I've been in a car that had this issue fixed by Fairbanks back in the 80s, and even with the restrictor, with the 5.0 lever that car will launch you forward on a 1-2 shift like you wouldn't believe with a stock 383.
Posted By: John_Kunkel
Re: can an auto trans shift "too hard", causing damage? - 02/20/14 08:51 PM
Overlap on the 1-2 upshift isn't caused by the lever ratio, it's caused by a rear servo that's slow to release.
As I've stated many times, shift phenomenon observed on jackstands isn't the same as when the car is under power.
Posted By: GTX MATT
Re: can an auto trans shift "too hard", causing damage? - 02/20/14 09:11 PM
Yes but you can only get the rear servo to release so fast, no? You can only fit so much spring in there.
What changes on jackstands vs out on the road? I'm just going off of what Fairbanks was doing in the 80s.
Posted By: John_Kunkel
Re: can an auto trans shift "too hard", causing damage? - 02/21/14 01:35 AM
When under power the car's momentum will "drive through" some overlap so it's barely noticeable, when it's on jackstands there is minimal load on the trans so overlap becomes more visible.
Posted By: GTX MATT
Re: can an auto trans shift "too hard", causing damage? - 02/21/14 08:29 AM
Quote:
When under power the car's momentum will "drive through" some overlap so it's barely noticeable, when it's on jackstands there is minimal load on the trans so overlap becomes more visible.
Thats kind of what I figured, but I thought that was the idea behind putting it on the lift also, on the road you wouldn't notice it or you would assume it was barking the tires because of a hard apply rather than a bind between gears. Would it be okay for the car to do this when there's no load on it?
Posted By: goldmember
Re: can an auto trans shift "too hard", causing damage? - 02/21/14 08:33 AM
Quote:
When under power the car's momentum will "drive through" some overlap so it's barely noticeable, when it's on jackstands there is minimal load on the trans so overlap becomes more visible.
But too many think a hard(often with lot's of overlap) shift is great.
Posted By: slantzilla
Re: can an auto trans shift "too hard", causing damage? - 02/21/14 10:18 AM
When driving too much overlap will pull the nose of the car down. A good shift will lift the nose.
Posted By: JohnRR
Re: can an auto trans shift "too hard", causing damage? - 02/21/14 03:45 PM
Quote:
Quote:
When under power the car's momentum will "drive through" some overlap so it's barely noticeable, when it's on jackstands there is minimal load on the trans so overlap becomes more visible.
Thats kind of what I figured, but I thought that was the idea behind putting it on the lift also, on the road you wouldn't notice it or you would assume it was barking the tires because of a hard apply rather than a bind between gears. Would it be okay for the car to do this when there's no load on it?
The 727 by design has overlap of the 2-3 , Chrysler engineers put a lot of thought and effort into making it has minimal as possible ...
Add a shift kit and you screw that all up ...
As John K said , running it on a lift is not going to tell you what you think it is .
Posted By: nytemuvr
Re: can an auto trans shift "too hard", causing damage? - 02/21/14 08:18 PM
Get a torque strap as even driving around town under light throttle is hard on the rubber engine mounts. I put a Transpak and reconfigured the valve body, removed the accumulator piston when my Challenger was 6 months old. I had to change driver side motor mounts a lot. But once I started a powerstand and let off the brakes it would sit in one place and shift though the gears burning the tires off. That transmission still snapped 2nd gear rubber in drive on a WOT until I rebuilt it at 186K miles in '95. I returned it to mostly stock configuration then, but it still picks up 2nd gear rubber as it did from the factory in '71 with Polyglas tires. It jumps sideways about a foot on a WOT 1-2 shift in drive now. [Email]340ci@400+[/Email] hp, 400 hp was as high as the old analog dynos registered. Stock Mopar 2850 rpm torque converter, 3.55 SG. 5.0 lever is really hard on everything.