Transmission Question

[84mudmachine]

I have a 84 k5 with a th350 in it, and it seems to have a hard time in reverse when it has sit and cooled down. It has been doing this for the past year, so it not like it just started. It shift fine and you feel it engage, but it seems that you need to give it a lot of gas to move it in reverse. It also seems to do better when you drive around and the transmission has warmed up. Do you guys have any idea to what might be causing this. The transmission was rebuilt by the po, at least that was what he said. With what the po said to me, it might have less than 5000 miles on it since rebuild. The transmission doesn't have any problem going forward, runs very smooth through all gears. Any ideas?

 

[84mudmachine]

Any one?

 

[diesel4me]

I wish I knew....

I too am the not so proud owner of a TH350 that has NO reverse,but all the foreward gears work fine--my truck had a "delay" in reverse,it would take a second or two to shift into reverse for many years,but it didnt slip or feel like it was dragging like the brakes were on or anything--one day I went to back it out of the yard and all I got was a lurch,then nothing,except a slight buzzing noise--now its silent as a tomb in reverse,and NO reverse at all,its just like neutral!-

-I dropped the pan,the fluid looked good,not much clutch material or filings in the pan(much to my suprise,since I plowed with this truck a lot,and worked it pretty hard!)--I have suspicions it might be a problem in the valve body,maybe one of the check balls got swallowed up or a seal on the clutch apply piston got ripped or hard and wont apply pressure to the reverse clutches-I tried new filter and fluid,no change--I could use the truck around the yard if I got reverse to work again,but no luck-
-whatever it is,I'm not fixing the truck anymore,its too far rotted and has a busted windsheild,too many sins to bother anymore..gonna scrap it as soon as the snow melts--might be june the way its going--its snowing again right now,and more coming saturday..

 

[84mudmachine]

I just wonder why it feels normal after the trany is warm, it moves in reverse very nice then. I was looking at some additives for the trany, and I think I will try Lucas Transmission Additive. It also might be a bit low, so I will just add some of this.

 

[diesel4me]

you cant hurt it any more ...

I have seen the Lucas stuff work on some really junk tranny's--its a good thing to try--your tranny probably has a seal that has gone hard with age,and it doesnt want to seal good enough when cold to apply pressure to the reverse clutch--your tranny MIGHT have been rebuilt,or it might just be the owners fantasy--my truck suppposedly has a "rebuilt" TH400,but I wonder if it was just a filter change sometimes! --some shops "cheat" and only change the seals and clutches in the foreward gears,to do the reverse clutches its a lot more work and time,since they are the first ones in and the last to come out,hidden way back near the tailshaft--unfortunately they do sometimes fail after a rebuild that didnt include the reverse clutches and seals--since most cars dont see much action in reverse,unless they get stuck in snow occaisionally,they seldom croak,so many shops take the easy way out..--but in a blazer or 4x4 truck,they get whaled on plowing and off roading,and many more of them die than the car ones do--reverse is usually the first gear you lose in a TH350 tranny,then the other gears dissapear shortly thereafter...

 

[84mudmachine]

I figure its woth a try...............thanks

 

[R72K5]

sounds like is tired transmission, is fluid dark or smelly, not fresh ATF smelly ? or old smelly?
can try additives as a magic temporary fix, but can only work so well, and for so long

if trans is really old

PO's love to say this or that is rebuilt and when its really not

90% of the time if theres no receipts then its a lie

good luck

 

[84mudmachine]

No, the fluid looks like it just got changed, and has looked like that since I bought it a couple of years ago. Up to a month ago, this truck was something I drove maybe once a week, now it is a dd.

 

[Nonesuch]

A three speed auto is very simple to rebuild. It would be against any shops best interest, if they offer any type of warranty, not to replace all of the seals. What they normally skimp on, and can get away with, is not replacing the bands or steels and sometimes the clutches themselves (called frictions). They also can do most rebuilds without checking the clutch pack clearance tolerances and be ok. It is not one tiny bit harder to rebuild the forward clutch and not go ahead and simply remove the direct clutch, which has nothing holding it in the case once the pump is removed. Then move on to removing one snap ring below that and one bolt under the valve body to pull the intermediate clutch assembly. You don't even have to pull the gears out unless you doing a full out rebuild. The valve body has a ton of valves and junk but is also pretty stinking easy to go through.





I had a tranny 'rebuilt' once by a shop and the very next day it went out again. I took it back and they blamed me and my 'hot rodded' 200K mile engine. It looked good and had TPI on it but it was stock otherwise. So they 'fixed' it again and told me they would not warranty it again. Since that bad experience, I started doing it myself. It is tons cheaper and at least I know what I did and didn't replace.

I know I didn't help you but I do suggest getting your self a book on how to rebuild the sucker yourself. That is if you can afford not to drive it for a while.