94 s-10 blazer 4x4 with 4.3 auto OD w/push button transfer case

Last week I let my Brother borrow my blazer while I fixed his car. Somehow he got the 4x4 into 4lo and was driving like this for a couple days. He said it wouldn't go. Well duh! He went to work at 45mph for 12 miles each way for 3 days!!!

Anyways now it won't shift from 1-2 unless I let off the throttle. After that it shifts fine from 2-3-OD. Fluid looks dark and smells burnt.

Going to change filter 1st when I get a chance. I am assuming he overheated the trans.

Any ideas??

Thanks

Jason

 

How many miles are on the transmission? Or the vehicle if you think it may be the original? That number may give a hint as to what happened. If it's close to or above 200K, I'm going to assume that the 1-2 accumulator piston is a bit worn and that combined with the low RPM shift points as described below are what could have been the demise of the 2-4 band. That's just my guess though.

I read that while in 4Lo, the trans shifts earlier to prevent running the engine at really high RPMs. However that's about all it said as far as how 4Lo affects shifting. Should that damage a transmission? I wouldn't think so. The transmission could have been overheated however by 45mph I would think the converter would have locked. The overheating is very possible as well but since you said it is slipping I'm more likely to stick with my guess that the band is smoked. I would get a professionals opinion though.

 

There is about 127,000 give or take. I think it is original. Up until then it shifted great and drove fine. I have owned it about 5 years now. Trans fluid up until then was bright red red.

 

Filter is a good place to start, but you might as well change the fluid while you're in there especially since you said its black and smells burnt

 

When you drop the pan and do the filter change, be sure to note how much black sludge is in the bottom as well as stuck to the magnet. If it's a lot, do a search for "4L60E/700R4". I put up a post on some problems as well as a long list of Problems/Causes/Solutions that I found on other sites.

In my opinion changing fluid/filter is not going to do anything for you until you get the real problem fixed. But you can give it a shot. I'm wrong at least half the time though. I just like to give worst-case scenarios so there can't be any surprises.

 

Finally got around to dropping the pan. couple chunks of metal in the bottom and on magnet. One the size of a dime. For sure I think this trans is toast now. Worth a shot I guess.

Haven't decided if i want to rebuild it or just junk it. I only paid 2500 for it 5 years ago. Just mainly used it for work and back.

 

Looks like it's time for replace or repair. If you're located anywhere near eastern Nebraska I'd be interested in the core.

 

Sorry located in N. Illinois.