[tazntown9127]

my 95 z71 4speed automatic was rebuilt about 1 year ago.never had any problems until the other day.went to work all's well.leave and i've lost overdrive.2miles later lose third.then second.all i have now is first and reverse.if i drive down the road it stays in first till i let off gas then nothing please help thanks

[Crosley]

I would scan the vehicle with a proper scanner. Read the data stream to see if the PCM is telling the trans to shift. Check for other items out of parameters

Does the speed-O function correctly?

[tazntown9127]

speedometer is working.will have to get it to a shop for scan after holiday thanks

[buickelectra225]

if its a 95 you can scan it for problems,it should show electril faults and major mechanical faults.try just checking the fluid,first and reverse are under the least stress and are usually the last to give under major slippage problems.


it sounds like ur having a problem with line pressure,because ive been working transmissions for over six years and thats not a common problem what youve described.


does the trans make a whining sound,if it does that would mean the filter is clogged and it isnt getting fluid to the trans.when first works does it slip at all?

[tazntown9127]

transmission is whining a little will have to check out filter first.then will go get scan.1 st gear is real strong no slippage at all reverse comes and goes.thank for the help guys

[tnsmith10]

Originally Posted by tazntown9127

transmission is whining a little will have to check out filter first.then will go get scan.1 st gear is real strong no slippage at all reverse comes and goes.thank for the help guys

if 1st gear is holding fine with no slippage, but reverse is slipping/not engaging at times, and with no 2nd 3rd or 4th, id say the problem is in the reverse input drum, and probably the input drum as well. a band goes around the reverse input drum for 2nd and 4th and the 3-4 clutch pack is in the input drum.
as far as the reverse issue goes, the piston in the reverse input drum has a small checkball in it and if trash were to get into the drum, it could keep reverse from working or cause slip if trash is keeping the checkball in the piston from seating.
as mentioned it needs to be scanned for codes and a pan drop done to see if it just coming apart internally.
also the tps will also need to be checked out as well, they can be the cause of transmission failure and not have a trouble code in the computer. not a common problem with gm, but i have seen it.