transmission (?) grinding when stopping

[tEXmEX]

Hi folks,

I usually find the answers to questions without having to post them, so thanks to all you guys for that, but I have an issue now with my 97 Sport 4.0 4x4 auto [edit: mileage = 148K] that I haven't turned up in searches. Moderators, please feel free to redirect me if I missed the answer somewhere...

The story: About 2 months ago I was starting out on a 2500-mile round-trip journey in the Ex and while speeding down the interstate through some mountains, the "O/D off" light began blinking. I hadn't turned the O/D off despite the hilly road, so figured that was my bad and the computer was just angry at me for having to work too hard; stopped, disconnected and then reconnected the + battery terminal to reset the light, and carried on without incident for most of the rest of the trip. On my way home, and nearly at the end of the trip, the "O/D" light began flashing again, only this time I hadn't really been working the truck hard (as I had the first time). Again, popped the battery cable on and off, problem "solved."

Truck was then fine until yesterday. I left home and then at the first stop sign, as I was slowing to a stop (so from ~10 to 0 mph), there was a horrible grinding and clunking noise from the front end, with an accompanying shudder as the truck stopped. Pulled away from the stop and the first couple seconds it felt like it was shifting roughly from 1st to 2nd, then ran fine until the next full stop. I found that I could mostly avoid the issue if I shifted to N as I was slowing, then when I wanted to go again, I took my foot off the brake and shifted to D. If I left my foot on the brake when putting it back into D, I still had the rough upshifts. The "O/D off" light began flashing again as this started happening, and now when I try disconnecting the battery, it makes no difference and the light comes back on regardless, even before I start driving anywhere.

So, all that to ask... is my tranny shot?

Thanks in advance for any sage thoughts!

 

[tEXmEX]

bump

 

[05fronty]

yea man sorry for the bad news but sounds as though your gears are starting to mesh..have you checked the fluid? what color is it?

 

[tEXmEX]

I was afraid of that... Fluid level is normal, color is light red but pretty dirty, streaked with gray/black.

 

[05fronty]

yea man all signs of a bad trans the streaks are from the burnt clutch disc inside the trans mixed with metal shavings from the gears..the only good thing is that atleast the transmissions are pretty easy to find

 

[joecrna]

First, a flashing OD off light is the transmissions version of a check engine light. Second, you have the 5R55E transmission. Search the stickies in the transmission forum and maybe take a look at the valve body rebuild diary. Do your symptoms seem like any of those mentioned in these other threads? Maybe the shift flare?

The transmission infrequently looses hard parts (planetaries, clutches etc). Most problems are easily fixed by changing the fluid and filter while fixing the valve body (the real source of the problems). This can be fairly easily done without spending a couple thousand dollars at the local trans shop. A rebuilt valve body is even available from Central valve bodies. A reasonably simple remove and replace procedure.

You might be one of the relatively unfortunate ones to really need major internal work but if I were you, i would do a lttle searching on here first. If you keep driving it much without fixing it, you most certainly will need major work including hard parts.

 

[tEXmEX]

Thanks, Joe. I'll do some more poking around on this site. Apparently the code it is throwing indicates excessive torque converter slippage. I won't be driving it again until I can either fix it myself or have it done if it appears more serious.

 

[joecrna]

Even that torque converter slippage may be something valve body related and a relatively easy fix. It is more likely to be a poorly functioning TCC selonoid than worn friction discs in the torque converter lockup clutch. Try not to drive it too much. When the torque converter slips it builds hugh heat real fast. This will damage gaskets, seals etc..