I have a 97 Bravada and I took the Tranny valve body out to clean it because I was not getting OD all the time. (Dirty Fluid) I have done this before and it worked ok for a while after. This time I cleaned it all out and now I do not have reverse. I can feel it go into reverse, however when I rev the engine it does nothing. I can tell some thing is happening though because the engine revs different when it is in Neutral. And I can hear something in the ways of the tranny slipping when I rev it in reverse. Like a valve is not letting the fluid flow completely making it slip. I know that I put everything back together correctly. I used to be a mechanic however I have never been a tranny guy. Also, I adjusted the neutral safety switch. Would this have anything to do with not going into reverse? Of course it would be an electrical thing then!!! At the ends of my wits on this one. Took it apart and checked everything over once already and just reassembled it again to have the same thing happen with not getting reverse. Thanks, John

Here's a good thread that might help:

http://forums.hybridz.org/showthread.php?t=116401

If the gear range selector switch (neutral safety switch) does not indicate R that may be a problem.

Also, did you remove the valve body for cleaning, or only pull the spools with the valve body in place?

Thanks for the reply's. First off, yes I removed the vavle body from the tranny. I took the spool valves out of the valve body and cleaned everything and reassembled it. I have done this before and never had a problem. I took the valve body out again tonight to check it all out again. I am going to make sure that I assembled it correctly. I did damage the TCC PWM Soleniod when I took this apart and ended up replacing it. I thought maybe that was the problem however, that did not fix it.
I did notice that when I put the vehicle in neutral, running or not, I can not move the vehicle at all. It is like there is something locked in place that will not allow it to move in reverse. I have not driven it down the road however in the driveway I can move forward. However like I said, I can not get it to move in reverse running or not. I tried it in neutral, reverse and forward with the engine off and the key to the on position, and it would not move like I stated. Hopefully this will help in diagnosing what the heck is wrong with this. This is very frusterating being I have done this before and did not have any issues at all and this time I got problems.
Does the location of the neutral safety switch have anything to do with this? It has not been adjusted correctly since the last time I fixed it. i never had reverse lights and it would not start in neutral. Now it does but not reverse!!!
this is killing me not knowing what is wrong. Thanks again for any info. John

Something else I just read and never heard about before. I read that pouring most of the tranny fluid in to the tranny all at once and then running the engine and checking the fluid level. I have never heard of not doing this. I did this both times I have had it apart this time and had the same results.
So I guess I am asking if anyone else has ever heard of this? I read that you should put a little bit in and then start the engine and add a little and check it and add and check until the level is full. I guess it could get air locked if all the fluid was put in all at once. Never heard of this before though.

Anybody heard of this?
Thanks,
John

Surely the parking pawl is not engaged when in neutral and reverse???? Did you put that assemply back together properly?

The parking paw looks to be working fine. I checked that last evening before I took the valve body out again. I took the valve body all apart again today and I had everything put back together correctly. If the parking paw was not correct I would think that it would not go forward also.
Or am I incorrect in that theory? I am going to reassemble it tonight and add tranny fluid a little at time and see what happens. I am not sure what else to do at this point if it does not work this time!!!!!!! Step back and punt I guess!!! HA! HA!
Thanks for your reply.

John

I must of misunderstood your post. You said "I tried it in neutral, reverse and forward with the engine off and the key to the on position, and it would not move like I stated." When you say "would not move" do you mean not move by physically pushing it or with engine acceleration with engine off? Good luck with it and keep us posted.

:p Well, it always pays to pay attention to details when you are working on something. I am pretty good at paying attention to details however this one got me. The problem with my "No Reverse" was installing bolts in the incorrect locations. On my transmission there are 3 bolts that have 8mm heads on them and are little longer then the rest of the bolts. Well they belong in a "L" pattern by the accumulator and I had then located in a straight line in the incorrect holes. This caused them to contact what ever is about the valve body housing and causing it to not turn. This is why I could not move this in the reverse direction even when the engine was off. Luckily I did not over force my tranny under power because it could have cracked my housing and I would be installing a new tranny at this moment.
Well, chalk one up for lessons learned and one I will never forget.
Thank to all for your ideas.
Have a Great Day.

John :p

That will certainly cause a problem......I hadn't even thought about that one. When I disassembled mine I measured all bolts as they came out and labeled their location on a hand drawing. Glad you got it fixed.