I have an 87 cc dw 6.9 auto. A week ago towing a trailer loaded
(over 10,000lbs <14,000lbs) I put the truck in reverse like normal and began to apply throttle. Suddenly it let out a noise that I can best describe as "pulling an old choke cable through an old steel dash board." You know that slipping growl noise. So I let off and pulled forward and it was fine. Tried reverse again and same thing. This time I applied more throttle and around 1800 rpm the tranny began to chug(slip & grip) then locked in and the truck began to move.
It only does this with a heavy load, normal driving it's fine even when I powerbrake it.
You guys think it's time for a total rebuild or just clean the valve body?
Any ideas appreciated.
other details: I just service it with a new screen and fresh ATF.
The tranny has 140,000 miles
4.10 r&p
runs @ 185*-195* temp

 

ive got an 87 ext cab 6.9 that has a steel flatbed and ive hauled ove 16,000 with it thats about 21,000 gross and i put my tranny through hell and it aint hurt it but i live in a small town in missouri it would only cost about 300-400 bucks to do a complete rebuild on mine thats with a new touque converter it would prolly be way more out there ive about come to the conclusion if it ever goes out i will slap a 4 or 5 speed in it for better pulling

 

Truth be known it may wieght more than 14,000lbs. The trailer is a costom built 5th wheel 34 ft long tri axle. I'm hauling 200 cedar trees that are about 5" diameter and 30+ feet long. But that's besides the point. What has me is it's only in reverse! Could it be a sticking valve or a wore band? I'm hoping some tranny experts chime in.
This truck for me is comfy, If I want to shift gears I'll jump in my Samurai and go wheelin, so manual trans is not an option.
As for ATF I think I use mercon/dexronIII.

 

i would look around and see how much it is to rebuild it its cheap here but dependin on where you live it might be alot more if it only does it in revers then i wouldnt think it was the valve body unless its not ingaugin the gear all the way

 

thats the reason i had mine rebuilt put it in reverse and made aloud niose and would not move but would drive forward so I drove to the tranny shop mech said I was lucky alot of stuff was tore up whoever worked on it prior had mixed up some parts. I had been driveing since I got with no problems untill that moment

 

87CC have you ever done or had the trans band(s) adjusted. The shift linkage could also be part of the problem......if it is holding the PNP switch out of the proper location it can make things slip......

 

does it lurch forward when you start it? mine does that and the shop said it could be your linkage is out or the cluches are siesing together

 

Never adjusted bands on this. Talked with a shop and they said theres some sprag or something that could be slipping, I don't know. For $800 I can give them My old one and get a fresh rebuild with a new torque converter. Sounds like this is what I'll do or rebuild mine but by the time I get a kit and new TC the price will be up there anyway. Plus his comes with a warranty.