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Trans kickdown lever question

Posted By: volaredon

Trans kickdown lever question - 03/02/24 11:32 PM

This is on a 46re in a Durango.
I have this trans all blown apart right now.
I noticed that it only has a "2.5" lever in it. I never knew they started so low. I thought "3.8" was the low point.
I've seen info on this subject before but that info is currently "buried" somewhere.
Why would they have put such a low rate lever into something like this, and what would be the advantage/disadvantage of changing it now while it's apart?
The valve body already has had a TF-ODJR shift kit in it for at least the last 60k, and I'm not looking to touch the vb except to disassemble it, clean it and put back in just as it is. I did buy raybestos HD kevlar bands for it. 4wd, mostly daily driver, but I do pull a 4k lb camper, a few times a year with it. And lighter duty towing than that, of lawn equipment/ once a week in the warm season in between campouts. My camper is a Trail manor (very similar to a Hi-Lo) so the top collapses down for towing.
Usually 140-150 miles a shot, each time I pull the camper, 60 miles a shot with the mowers.
Posted By: JohnRR

Re: Trans kickdown lever question - 03/03/24 12:38 AM

Originally Posted by volaredon
This is on a 46re in a Durango.
I have this trans all blown apart right now.
I noticed that it only has a "2.5" lever in it. I never knew they started so low. I thought "3.8" was the low point.
I've seen info on this subject before but that info is currently "buried" somewhere.
Why would they have put such a low rate lever into something like this, and what would be the advantage/disadvantage of changing it now while it's apart?
The valve body already has had a TF-ODJR shift kit in it for at least the last 60k, and I'm not looking to touch the vb except to disassemble it, clean it and put back in just as it is. I did buy raybestos HD kevlar bands for it. 4wd, mostly daily driver, but I do pull a 4k lb camper, a few times a year with it. And lighter duty towing than that, of lawn equipment/ once a week in the warm season in between campouts. My camper is a Trail manor (very similar to a Hi-Lo) so the top collapses down for towing.
Usually 140-150 miles a shot, each time I pull the camper, 60 miles a shot with the mowers.


2.5 , is this the front band apply lever you are talking about ?? If so get a 3.8 or a 4.2 .

As far as your band selection , don't use the Kevlar band in the front position , it's ok to grab a drum that is not spinning but grabbing the front drum while it is spinning is eventually to smoke it . Get a 727 band for the front, they have a greater amount of friction material than the later bands.
Posted By: dvw

Re: Trans kickdown lever question - 03/03/24 12:42 AM

There are 2.5, 2.7, 3.2, 3.8, 4.2, 5.0 ratio levers. The higher the ratio the more leverage on the 2nd gear band. If the band looks good I'd leave it alone.
Doug
Posted By: volaredon

Re: Trans kickdown lever question - 03/03/24 12:43 AM

yeah this is the front band apply lever.

how would a 3.8/4.2 be better than a 2.5? would I adjust the front band "less turns out" from the 72 in/lb? I knew a guy at the dealer that never did the "X" turns out from 72... just watched the clearance but I forgot how much.
Posted By: JohnRR

Re: Trans kickdown lever question - 03/03/24 12:46 AM

Originally Posted by volaredon
yeah this is the front band apply lever.

how would a 3.8/4.2 be better than a 2.5? would I adjust the front band "less turns out" from the 72 in/lb? I knew a guy at the dealer that never did the "X" turns out from 72... just watched the clearance but I forgot how much.


The higher the number the more leverage it applies , if it was working ok you could just leave it , what does the band you took out look like ??
Posted By: volaredon

Re: Trans kickdown lever question - 03/03/24 02:18 AM

the old band wasn't terrible, wasn't burnt, no chunks, etc I'm replacing it because I'm in there anyway. I know this isnt a race vehicle but it is a heavy 4wd that occasionally tows....
the forward clutch pack was what fried inside. but I only want to do this once. (rear clutch, by position in trans case) Hi reverse clutches, and the clutches in the OD looked perfect.
the belleville spring wasn't cracked but had radial grooves worn in each "finger". I already have a new one of those. The plastic spacer was a melted blob behind the snap ring as well.
kind of a weird failure, it was great until the day after I replaced the evaporator and heater core, and it started shuddering when i pulled out of a gas station like someone flipped a switch. shuddered in 1-2, I believe in 3rd too, (its been out of the durango since July/ I put a junkyard unit in there in its place which went a whole 3 months) But if I could baby it til it hit OD, it was fine at that point. It wasn't a "small" shudder either. Right off the bat. It was perfectly fine right up until that point. being it happened so suddenly would I be looking for a stuck valve or something like that?
Posted By: John_Kunkel

Re: Trans kickdown lever question - 03/03/24 05:35 PM

Originally Posted by volaredon
would I adjust the front band "less turns out" from the 72 in/lb? I knew a guy at the dealer that never did the "X" turns out from 72... just watched the clearance but I forgot how much.


The number of turns out depends on the lever ratio and type of front servo. To keep the servo piston travel about the same with the different lever ratios, a lower ratio like 2.5 needs more turns out than a 3.8 or 4.2. Some people just set the plunger gap at 5/16" or 3/8" which is OK on the bench but the turns out method is more practical in the car.

The later "controlled load" servo plunger doesn't fully retract after the 2-3 upshift, so the band adjustment needs to be looser yet.
Posted By: volaredon

Re: Trans kickdown lever question - 03/03/24 07:35 PM

I'm putting aftermarket superior brand servos in with this rebuild.
Whether I leave the 2.5 arm in, or whether I change it to something else would THAT change make for a different adjustment?
Posted By: John_Kunkel

Re: Trans kickdown lever question - 03/03/24 08:02 PM


It makes the "turns out" adjustment different but, with the aftermarket servos, the 5/16" or 3/8" air gap adjustment will work with any lever. The length of travel of the servo effects shift timing so you want to keep it the same with all lever ratios.
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