TheAMCForum.com Homepage
Forum Home Forum Home > The Garage > AMC 6 Cylinder Engine Repair and Modifications
  New Posts New Posts RSS Feed - budget 258 rebuild
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Click for TheAMCForum Rules / Click for PDF version of Forum Rules
Your donations help keep this valuable resource free and growing. Thank you.

budget 258 rebuild

 Post Reply Post Reply Page  <1 121314
Author
Message
TheBirdman View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Oct/25/2017
Location: Sioux Falls, SD
Status: Offline
Points: 76
Post Options Post Options   Thanks (0) Thanks(0)   Quote TheBirdman Quote  Post ReplyReply Direct Link To This Post Posted: Dec/17/2017 at 2:11pm
I had similar thoughts, but while i was trying to figure out the reverse shudder. I still dont knkw if reverse pressure goes off of the tv or if it gets constant pressure. I seem to remember reading something about the shift kit supplying extra reverse pressure, but i cant remember
1983 Eagle Wagon
4.0 from 93 cherokee
AW4, NP242, and EFI from 99 cherokee
Back to Top
TheBirdman View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Oct/25/2017
Location: Sioux Falls, SD
Status: Offline
Points: 76
Post Options Post Options   Thanks (0) Thanks(0)   Quote TheBirdman Quote  Post ReplyReply Direct Link To This Post Posted: Dec/17/2017 at 4:32pm
What I did is I put two marks on the linkage, one on the rod, and one on the wire. I measured the distance between them when set at WOT, and the distance when set at idle, then took half the difference and set it right inbetween. The shifts are back to where they should be, but my reverse vibration has returned. Seeing as it hasnt gone away after setting the linkage back to how it was means that the reverse vibration is not a product of a wrong TV setting.
Basically, when I give it any more than a little gas in reverse, it will vibrate. I used to think it was a shudder, but after looking up a few transmission shudders on youtube, this vibration isnt nearly as violent and doesnt actually affect the speed of the car, it just vibrates. I checked and put it in reverse, then gave it some throttle while holding the brake, and it does vibrate when stationary too. Has anybody else heard of something like this? I am hesitant to blame the torque converter, as it would seem like it would happen in the forward gears too if that were the case, and all 3 forward gears work fine. I read in this page: https://www.allpar.com/mopar/transmissions/torqueflite-fixes.html that there is a high pressure relief ball that is known to buzz in reverse, but it also says a transgo kit would correct that.

I am puzzled as to why it went away for a week or so after installing the shift kit, and now its back. Maybe the crappy fluid that was left in the cooler lines and torque converter when I drained the transmission is the culprit. I may try draining out some fluid from the cooler lines while its running, then refilling it with some good atf+4, instead of the cheapo oreilley atf I put in it before.


Edited by TheBirdman - Dec/17/2017 at 4:35pm
1983 Eagle Wagon
4.0 from 93 cherokee
AW4, NP242, and EFI from 99 cherokee
Back to Top
TheBirdman View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Oct/25/2017
Location: Sioux Falls, SD
Status: Offline
Points: 76
Post Options Post Options   Thanks (0) Thanks(0)   Quote TheBirdman Quote  Post ReplyReply Direct Link To This Post Posted: Dec/18/2017 at 10:41pm
Ha ha, silly me

The vibration isnt even the transmission at all, its the transfer case. It works fine in 4wd, and the reason I thought it went away for a week it that I was driving in 4wd for a week. Since I already knew my viscous coupling was shot, this news is like christmas.
1983 Eagle Wagon
4.0 from 93 cherokee
AW4, NP242, and EFI from 99 cherokee
Back to Top
billd View Drop Down
Moderator Group
Moderator Group

Forum Administrator

Joined: Jun/27/2007
Location: Iowa
Status: Offline
Points: 30894
Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Dec/18/2017 at 11:20pm
Vibrations related to a spinning part will do it any time that part spins - converter would vibrate depending on engine speed and never change based on vehicle direction since the engine is what is spinning it. 
Fluid, that sort of thing, can't cause a vibration.
Vibrations are caused when a spinning part isn't balanced or isn't spinning true. A spinning part that is wobbling due to a loose bearing, for example - but even at that, as long as it's balanced it shouldn't vibrate unless that part is really seriously out of whack. 
Anything in the transfer case that's causing a vibration would mean a totally worn part - something that is moving around instead of just turning. 
Check the driveshafts, yokes, etc. if one has a loose bearing, such as a shot pinion bearing or the output shaft bearings of the t-case are shot............. could vibrate. 

Shifting is handling by a balance between governor pressure and throttle pressure. It's a tug-o-war between the two.
As the vehicle moves faster it spins a governor in the transmission - weights move out against spring pressure raising governor pressure. As the gov pressure rises it wants to push the valves involved in shifting. Throttle pressure works against that. 
More throttle means you move the linkage and raise throttle pressure which pushes back against governor pressures and delays the shifts. Low throttle means lower throttle pressure and governor pressure overcomes it more easily and the transmission shifts.
So as you push the gas, you raise throttle pressure and that pushes back against governor pressure preventing the shift spools/valves from moving.
Let up on the gas and you let the throttle pressure drop and governor pressure overcomes throttle pressure sooner allowing upshifts sooner - but also against lower pressures so the shifts aren't as hard or harsh. 
That's the over-simplified version of what goes on. 
I have all of the charts of the time, the pressures as far as what they should be under what conditions and so on as I used to rebuild automatic transmissions as part of my job (and we did a whole semester on transmissions and differentials, etc. in college)
However, shift kits mean you throw all that out the window - a pro will do more than just toss a kit in and say there ya go........... 
I've seen parts literally SNAPPED OFF the case from messed up valve bodies and folks not getting some little thing right - even a piece of lint. I saw one that broke the case, and another that snapped the band solenoid clean off the case. The pressures were so high and the shifting was so out of time it wasn't fully out of one gear before the next applied and going down the road it tried to do two at once - the car jerked and things snapped. 
We had a test stand we could mount any automatic onto and literally run it as if in a car - testing shift points, pressures and so on. It had a Ford four cylinder engine to run it and the output shaft connected to a heavy counter-weight to simulate the car being on the road. Worked slick - that way you could test things out before it ever was released to a customer or put in a car. 
Back to Top
TheBirdman View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Oct/25/2017
Location: Sioux Falls, SD
Status: Offline
Points: 76
Post Options Post Options   Thanks (0) Thanks(0)   Quote TheBirdman Quote  Post ReplyReply Direct Link To This Post Posted: Dec/19/2017 at 12:36am
I checked the yolks when I was initially working on it, and they seem to be alright. The reason I suspect the viscous coupling is 1. I already know its shot, it let the silicone out a long time ago, and 2. it only vibrates in reverse under load in 2wd. It works fine, no noise or complaining in 4wd. Frankly, as long as its not a transmission problem, and it doesnt impact operation, I am happy enough to write it off as an 80s turd quirk.

I am already keeping an eye out for a new transfer case


Edited by TheBirdman - Dec/19/2017 at 12:39am
1983 Eagle Wagon
4.0 from 93 cherokee
AW4, NP242, and EFI from 99 cherokee
Back to Top
 Post Reply Post Reply Page  <1 121314
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.03
Copyright ©2001-2019 Web Wiz Ltd.

This page was generated in 0.422 seconds.
All content of this site Copyright © 2018 TheAMCForum unless otherwise noted, all rights reserved.
PROBLEMS LOGGING IN or REGISTERING:
If you have problems logging in or registering, then please contact a Moderator or