Hi all im new to the forum hope i dont bother anyone too much with this post as im sure there are post on this topic but i wont lie im too lazy to dig into the forums to find a fix to my problem anyways on to the story...

I have a 1997 Blazer 4wd 4.3 2 door i bought a couple months back after an identical blazer i had before this one started to over heat and it been sitting now, anyways my blazer now has had a small leak of tranny fluid up by the oil pan and i cant find where its leaking from but i havent been concerned about it and been topping off the fluid every week or so and the color of the fluid has been red and i havent had any issues with the transmission until the other day when i was on the highway when i got up to 60 it started to sound like i was at topped out speed at the gear i was in and it wouldn't shift into the next gear, so i pulled over and checked the fluid and it was slightly burnt but it was full so i tried to start driving and now i can only drive in 2nd gear with othe having any issues but when i slowly creep to 30 the rpms raise and it wont change gears but if i put the pedal to the floor it goes into 3rd roughly but it does go into 3rd and 4th doesnt seem to be too bad but the tranny is getting really hot and i can smell the fluid burning im also getting a check engine code for p1870 for trans slipping. If anyone has any solution or fix i can try first please feel free to pass on the info if you think the whole tranny needs to be fixed or replaced ill just swap it out from the other truck

 

If it got hot enough to burn the fluid then thats well over about 450 degrees. Unless there's an air leak into the trans fluid lines I doubt its being caused by the leak. A leak would have to be large enough to drip badly.

Maybe an oil cooler plugged up? Filter bad?

My guess is that the clutches are toast.

 

so tranny swap you're saying?

 

If it got that hot, Yes. That trans isn't too hard to change...not too heavy. I changed one in my S10 and the most difficult parts were getting the lines off and getting the bellhouse screw out that's near the gas pedal. I assume the Blazer chassis is similar.

I couldnt get wrenches on the lines so they were cut and reconnected with compression fittings. Worked perfectly. Then I pulled the drivers side carpet back and drilked a large hole thru the firewall to get a socket and extension on the bellhouse screw.

make sure to flush the torque converter, lines and trans cooler of old burned oil.

 

Yes, a used or rebuilt unit is about the only options. As mentioned you will need to flush cooler and lines. I would never use a torque converter from a failed unit over. Cant be flushed without cutting it open plus there is the lock-up clutch that will need to be replaced. If you buy used it should come with a converter if not get a remanufactured converter. The cooler lines will have clips on them under a plastic cap you pry loose on transmission. Top bell bolts can be reached by having the cross member removed and then lower the rear of the transmission. A 2-3 foot extension with a swivel will get them out. The extension that is used by most R&R guys is an impact with 1/2 female end and 3/8 male end. Also need to replace the input seal on the transfer case as that's where your fluid is leaking into.
Brad

 

"would never use a torque converter from a failed unit over."

yep. That leads to disaster. Cant get the junk out.

 

So when i swap out the tranny with my other 1997 blazer's tranny do i need to reprogram anything or will it automatically just start working as before since the model and build are identical

 

No programming, it’s plug and play. Are you doing this job or a shop?

 

im gonna be doing this project my self to save my self the cost of labor and parts ive called the local shop and they refuse to remove my transmission from my other blazer to swap it. So im just gonna figure it out any tips or advice