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View Full Version : 200-4R Reverse = Foward?


slaman37
05-21-2011, 11:45 AM
First, I would like to say Hi. First time poster on these boards.

A little about my ride and my problem. While I do not own a GN, (Wish I did, got really embarrassed by one back in high school '88) I do still have my '70 Monte Carlo from high school that I am doing a body off rebuild/update. I have retro fitted my 350 to TPI from an 89 IROC and modified it to a Speed Density set-up with a 200-4R trans out of an '85 Monte SS. Future dreams include adding a pair of turbos.

Now my problem. I got the 200-4R already pulled from the junk yard from a wrecked MCSS. I pulled the pan and although the fluid was looking burnt everything I could see was very clean. The TV cable did not get removed before whoever pulled it and was cut after apparently hanging from it. Which broke a spring that helps to return it to it's normal position down by the valve body. I pulled that apart and modified the spring (Bent) so that it would hold the cable correctly and took my chances and installed the tranny. Now I finally got to test drive it a couple days ago for the first time in 16 years and when I put it in Reverse it goes forward like it's in 1st gear. I took it to the end of my court and back and everything else seemed ok. I had it up to about 35mph but never really felt any shifts. btw I have a 3:73 posi so I would think it would have shifted into second by that speed and I did have excessively high rpms so I'm sure it at least was in 2nd.

So Why is it going into low when Reverse is selected? I think, big think there that they both run off the same gear set and it just that in reverse the forward clutch pack is not engaged... Is there an easy fix? Time to just go ahead and pull it and rebuild? Maybe that plunger got stuck in the valve body?

Sorry I know it's a long post but I wanted to give as much detail as I could. I have verified the shifter linkage and the TV cable set-up too.

Thanks,
Steve
http://i459.photobucket.com/albums/qq318/slaman37/th_100_7023.jpg (http://s459.photobucket.com/albums/qq318/slaman37/?action=view&current=100_7023.jpg)

Keller
05-21-2011, 10:02 PM
Sorry to hear you are stuck in the slow lane of IROC land. :winkgrin:

Maybe that plunger got stuck in the valve body?
Um, yeah...maybe. Can you feel spring tension on the TV cable? Do you have it connected to anything?

Not sure I would assume a trans with burnt fluid had decent clutches. Takes a lot of heat to burn them, or running without fluid.

As far as your issue, I would lean toward something other than the TV. Though the TV is a very important part of things shifting right. See the site for more info about how the 200-4R does its shifting.

slaman37
05-21-2011, 10:47 PM
Thanks for the reply. I know it won't be real fast anymore. I use to have it set up for drag racing with a big cam, 3500 stall and a full race prepped T-350 but I want a cruiser now. Plus I got plenty of room under that 6 foot long hood to put twin turbos on it one day...:)

I did check the TV cable again and I do have return pressure on it so I really don't think it's that. I was thinking maybe something in the low-reverse valve maybe? Possibly leaking by bad enough to prevent the Forward clutch from disengaging...

I did look through all 128, I think threads, in this section but none really had the same issues. I'll keep looking though. How hard is it really to rebuild these at home? Granted I'm not looking to make a 9 second car, maybe 13's and just want a nice cruiser that can light up the rears when I want to have a little fun. I think the TPI will provide a lot of low end torque when mated with the low 1st gear and 3:73's, which I'll need with the approx 3800lb curb weight of my car.

Back in '88 I pulled up behind one (GNX) at a light and revved my motor because I had heard they were fast and wanted to see just how fast... hmmmp that was a mistake... like where'd he go? It was embarrassing to say the least....

Thanks,
Steve

kenmosher
05-22-2011, 09:55 AM
Probably varnish/gunk in the reverse valve hanging the direct clutch or not engaging the low Reverse clutch. Take a look at the transmission section detailing valve body parts and rebuild steps.

http://www.gnttype.org/techarea/transmission/transpage.html

http://www.gnttype.org/techarea/transmission/Trans_shifting.html
http://www.gnttype.org/techarea/transmission/valvebody.html
http://www.gnttype.org/techarea/transmission/122a.gif
http://www.gnttype.org/techarea/transmission/200rebld.html

and here's the hydraulic circuit for reverse (attached)

slaman37
05-22-2011, 09:42 PM
Thank you so much. That hydraulic schematic help out a lot. So you think I could get away with a flush or is it time to just pull it and rebuild?

Thanks,
Steve

kenmosher
05-23-2011, 09:17 AM
I'm thinking it's rebuild time. It sounds almost like the direct clutch may have been warped/burned together.

Keller
05-23-2011, 12:37 PM
:ow: Been there, done that.

Imagine all of this being welded together. When the rebuilder sent the stack to me, I repeatedly threw it on the ground several times before anything broke off. That is what happens after standing on a trans brake too long. And possibly using the wrong fluid. I ended up with a trans that had first, reverse...and that was it. It only had 300 miles on it. :nope:

http://www.200raptor.com/REPP2004R.jpg

The fact that the trans had burnt fluid in it to start was a bad sign. I'd suggest rebuild, too. No telling what it has been subjected to.

slaman37
05-23-2011, 12:47 PM
Thanks guys. I kinda figured I'd be in for a rebuild. Not really what I wanted to hear but not unexpected. After all I only paid a $65 core charge for the tranny but was hoping I'd get lucky. Guess my luck is just holding as normal... lol.... Looks like I'll be saving up for some parts and go a head and get some goodies for it...