4L60E Slipping in O/D

Garage Mechanic's Companion · November 30, 2004

This has been an on going problem. Once the trans warms up or if you really flog the truck, the trans starts slipping in O/D (evident by the tach rising and speedo not, if you blip the throttle). If you leave it in O/D, the engine light comes on and and the trans goes into limp mode. If I put it into 3rd before the light comes on, everything locks up and the trans works fine.

I changed the fluid and filter and put in a bottle of Kleen Flo Auto trans conditioner. This has helped a bit, but still, if you really flog the truck, it'll start slipping again. So I've been driving it 3rd most of the time.

I have read else were in this forum that this is caused by valve body wear, but after 70K with a truck that is typically driven like a car?? That's pathetic!!

I checked the forum at LS1Tech looking for the same problem but most (if not all) of the slipping problems I noticed there were do to racing, definitely not my scene.

Anybody else had this experience? Is changing the valve body the only recourse? If so, what's involved? Any do's and don't's?

Thanks in Advance,

Derek

mcreyaufmiller · December 1, 2004

What code is coming up in the computer? This will tell you if you need the shift kit or not. If it is the P1870, this can be fixed with the Trans-go shift kit. Delivered to your door for about $55 and a half days work to install. Not bad to do if you are familiar with a TH-350 or a 700R-4. If this is your problem I would suggest ordering a new seperator plate and a aluminum piston at the same time. Check out www.bulkpart.com. They have most of the right answers and great prices!!

Mike

mcreyaufmiller · December 1, 2004

Sorry, I installed this kit and all of my tranny problems went away. It has a significiant 1-2 kick when cold, but it is a nice feel.

Mike

Garage Mechanic's Companion · December 3, 2004

Mike,

I can't remember the exact code numbers, but the code descriptions were:

1. General Transmission Fault

2. Transmission Slipping

Does this sound like the code number that you described?

Thanks in advance,

Derek

budhayes3 · December 3, 2004

Could be a couple different things, a worn accumulator piston or seal, bad servo seal, even worn 4th gear clutches I believe.

mcreyaufmiller · December 3, 2004

The codes I had were P1870. This translated to two different things, transfer case broken (auto Zone translation) or Transmission slippage, my problem. email the guys at www.bulkpart.com, describe the problem and they can halp you with parts. They are knowledgeable and friendly. Oh yeah, and they have great prices!

Mike

Garage Mechanic's Companion · December 6, 2004

I picked up a Transgo HD2 kit for $80.00. I'm going to give that a try.

Cheers,

Derek

Garage Mechanic's Companion · February 28, 2005

Hi All,

Just thought I would leave an update. I finally got a chance to install the HD2 kit on Friday afternoon. (Been traveling with work and have hardly been home since November).

This is a fantastic kit, trans works awesome now, all shifts are firm without being harsh, no more codes, etc. Everything inside seemed fine when I took it apart, fluid wasn't burnt, so I think all of my problems were control system related.

I did find that one of the spool valves was misassembled from the factory, don't know enough to say whether this was part of the problem.

So with the money I saved from having somebody else fixing my trans, I bought a 9000 lb hoist (where has this thing been all my life?!?!).

Thanks to all that responded to my post.

Cheers,

Derek

mcreyaufmiller · February 28, 2005

Glad to hear that you got the problem fixed. I have found that most tranny problems can be fixed by some sort of shift kit. Maybe I should start installing them for people in the area. Anyway, I am glad to hear that all is well and congrats on saving all the money on the repair! That is the best part.