Author Topic: What RPM does your auto trans shift at?  (Read 778 times)

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Offline priya

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What RPM does your auto trans shift at?
« on: May 24, 2013, 11:39:39 AM »
I noticed when I have my Eagle at full throttle the automatic transmission shifts by itself at 3500 rpm which seems way to low to me.  I've tried shifting manually but when I do and delay the shift past 3500 I get a slow slippery sounding shift.  Is there something wrong with my trans and what RPM does you eagle shift at if you have it at full throttle in drive?

Offline TLC87Eagle

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Re: What RPM does your auto trans shift at?
« Reply #1 on: May 24, 2013, 01:44:07 PM »
My Eagle's trans has been rebuilt with about 15k miles on the rebuild, and shifts around 3300rpm with my foot in it. During real gentle starts, it will shift at 1500rpm. I will manually shift it if I need more power like getting on the interstate and such, and will shift a little over 4000rpm. Our 258 straight sixes though don't really liked to be revved past 4500rpm I've found. Even with performance upgrades, they will start to valve float above 4500rpm. They are low revving engines almost like diesels and make tons of torque down low from right off of idle to 2800rpm.

As far as the slippery feeling shifts, your second gear band may need adjusted in the trans. It explains how to do that adjustment in the service manual. Mine has nice firms shifts between gears even when in the throttle, so I wouldn't do too much hard shifting until you check the adjustment on the second gear band. That's actually what broke in mine several years ago, when I had to have it rebuilt. I lost second gear completely. I would start out, and when it shifted into second, the engine would just rev all the way up and then go into drive.
1987 Eagle Wagon Limited

Offline priya

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Re: What RPM does your auto trans shift at?
« Reply #2 on: May 24, 2013, 03:13:57 PM »
By "with my foot in it" do you mean right to the floor?

Offline TLC87Eagle

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Re: What RPM does your auto trans shift at?
« Reply #3 on: May 24, 2013, 05:06:27 PM »
By "with my foot in it" do you mean right to the floor?

Yeah, that's what I meant by that  ;D
1987 Eagle Wagon Limited

Offline carnuck

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Re: What RPM does your auto trans shift at?
« Reply #4 on: May 24, 2013, 10:41:33 PM »
How long has it been since it was serviced? Passing gear adjusted?
FOR SALE
'87 Comanche 4.0L AW4/NP242 3.73 gears, lifted 5" on near new 33" tires $3500 obo
'82 Eagle Wagon (Brown Betty) 4.2L/727/NP229 and soon 8.25 rear axle and non-vacuum 3.08 front to match. 235/75/15 tires. It's down to minor body work (someone creamed my driver's door but I have another in good shape) almost rust free and interior work (seats are worn and carpet torn). $2000 but about to go up due to more work being done.

Pics of my other for sale stuff http://tinyurl.com/jimsclads

Offline priya

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Re: What RPM does your auto trans shift at?
« Reply #5 on: May 24, 2013, 10:54:13 PM »
How long has it been since it was serviced? Passing gear adjusted?

Never been serviced that I know of.  We pulled it out of my Eagle wagon in 2007 which had been sitting in the field since 1997. It was working well in the wagon when it was parked.  The pan was removed and cleaned, new filter (I think) and new trans fluid in 2012.  I don't know what it means to adjust the passing gear, we hooked up the kickdown linkage and shift linkage, don' t know if that has anything to do with it.
« Last Edit: May 24, 2013, 10:55:48 PM by priya »

Offline carnuck

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Re: What RPM does your auto trans shift at?
« Reply #6 on: May 24, 2013, 11:20:15 PM »
The kickdown linkage controls when the trans upshifts. Right next to the carb is the slotted portion that looks sort of like it's made from a coat hanger and there is a bolt that clamps it to the rest of the linkage. If you loosen that bolt and extend the slotted part forward (essentially making the kickdown linkage longer) the RPMs will go higher before upshifting. I can't recall the front axle of yours being vacuum or not, but if it is, sometimes the lines leak vacuum and allow the axle and/or the tcase to partially disengage and make that noise you are describing.
   I really prefer the Lokar passing gear cable setup instead of the sloppy link rods.

PS: Changing the fluid and filter is servicing, albeit not adjusting the bands. I increased the line pressure in my trans with a can of STP engine oil treatment put in (yes, in the trans).
FOR SALE
'87 Comanche 4.0L AW4/NP242 3.73 gears, lifted 5" on near new 33" tires $3500 obo
'82 Eagle Wagon (Brown Betty) 4.2L/727/NP229 and soon 8.25 rear axle and non-vacuum 3.08 front to match. 235/75/15 tires. It's down to minor body work (someone creamed my driver's door but I have another in good shape) almost rust free and interior work (seats are worn and carpet torn). $2000 but about to go up due to more work being done.

Pics of my other for sale stuff http://tinyurl.com/jimsclads

Offline priya

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Re: What RPM does your auto trans shift at?
« Reply #7 on: May 24, 2013, 11:26:00 PM »
The front axle is not vacuum, its full time 4wd.  Thanks for the info on the kickdown linkage, that sounds great and easy to do.

Offline maximus7001

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Re: What RPM does your auto trans shift at?
« Reply #8 on: May 25, 2013, 07:14:33 AM »
The kickdown linkage controls when the trans upshifts. Right next to the carb is the slotted portion that looks sort of like it's made from a coat hanger and there is a bolt that clamps it to the rest of the linkage. If you loosen that bolt and extend the slotted part forward (essentially making the kickdown linkage longer) the RPMs will go higher before upshifting. I can't recall the front axle of yours being vacuum or not, but if it is, sometimes the lines leak vacuum and allow the axle and/or the tcase to partially disengage and make that noise you are describing.
   I really prefer the Lokar passing gear cable setup instead of the sloppy link rods.

PS: Changing the fluid and filter is servicing, albeit not adjusting the bands. I increased the line pressure in my trans with a can of STP engine oil treatment put in (yes, in the trans).

How long ago did you adds the STP? And how did you measure the line pressure? Do you have a before and after PSI?
1968 Javelin SST 290
1981 Concord DL sedan, vintage red metallic (now parts car)
1985 Eagle wagon, same colour as the concord (project car/daily driver)
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Offline carnuck

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Re: What RPM does your auto trans shift at?
« Reply #9 on: May 25, 2013, 02:25:22 PM »
Years ago I used the gauges screwed into the test ports of the trans and gained 5 lbs pressure and a shorter time to build it up. Nowadays it's more seat of the pants. My 727 was slow engaging when cold when I first put it in (used from a Grand Wagoneer with 100,000 miles on it. Pan was clean and filter was new) I did it a year ago, about a month after I put the trans in.
   I did it to the TH400 in my '73 Jeep J4000 10 years ago and it ran fine hauling 5th wheel and 6500 lb loads until I rolled the truck a couple years ago (black horse in the middle of the road on a gravel switchback around midnight. I swerved into the ditch around it and flipped the truck or we would've gone into the river over the waterfall). I'll be rebuilding that trans to put in my Honcho with a different output shaft and New Venture "sleeve" to run a NV242 tcase.
FOR SALE
'87 Comanche 4.0L AW4/NP242 3.73 gears, lifted 5" on near new 33" tires $3500 obo
'82 Eagle Wagon (Brown Betty) 4.2L/727/NP229 and soon 8.25 rear axle and non-vacuum 3.08 front to match. 235/75/15 tires. It's down to minor body work (someone creamed my driver's door but I have another in good shape) almost rust free and interior work (seats are worn and carpet torn). $2000 but about to go up due to more work being done.

Pics of my other for sale stuff http://tinyurl.com/jimsclads

 

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