2000 4x4 blazer 4.3 liter. I was doing some front end work and also replaced the radiator. The truck had been sitting for a while and the battery was dead. Upon finally starting it the retaining clip for the tranny fluid cooling line to the radiator came loose. I lost a bit od fluid but the level was still good. The fluid sprayed all over the engine. I fixed the problem and got it started again. Now the tranny has no drive in reverse, rolls backwards in drive and no drive in any other gear. It does not slip out of park. A lot of rough noise underneath when attempting to shift. The 4x4 control is not in neutral and it seems to transfer correctly.The fluid level was in the hot zone after idling for a while and it felt pretty warm too. Any ideas before I spend too much money on a mechanic. Please Help.

 

Did you check the fluid level with the engine hot and running?
If you replaced the radiator, the fluid will be low ( there is a transmission cooler built into the rad), also if the line came loose and you lost more fluid, it's even lower.
Check the fluid again, with the engine hot and running, it's probably low.

 

Don't know if it would be the fluid though. If it is getting no drive in reverse and you have a lot of noise underneath it might just end up being a problem with the transmission iself. Like the gears are not catching right. I would drain the auto transmission fluid and look for metal shavings in the fluid. It would be an indication that the parts are not aligning correctly

 

Time for a new tranny gasket and filter. Which will give ya an idea. Not hard to do but can be a pain getting the pan back up there. I'm not sure if chevy did the same exact thing as they did with the 2 dr. with having the shifting cables attach to the tranny pan.

 

Nations,

It seems odd to me that you only did front end work and a radiator and now you have transmission issues. If it were me, I'd look real close at the radiator installation. I'm suspicious since you had a tranny line pop off. You didn't state if it was the supply to the oil cooler (in the radiator) or the return. If it was the supply, just for kicks I would disconnect the return to make sure you have flow through the cooler.

My $0.02....
Bob

 

I too would look at the radiator end of things. The number one thing was posted once before, yet it is worthy of repeating.

You must check the tranny fluid level while the engine is running, and on level ground. I am willing to bet your low on fluid.

I would also look extremely closely at the cooler lines. Make sure they are not kinked at all. The slighest kink will restrict fluid flow and fry your tranny.

 

Definately do as the above post says.

Other things that I would like to add after working in a transmission shop as my previous job:
1. Don't put any "tranny fix in a can" into your transmission, it will make things worse. If that stuff really worked, there would be no transmission shops.
2. Over fill it by a half quart from where you think full is. It's not going to hurt it, it's better to have a little much than be way under.
3. Diagnose wether or not this is a hot or a cold issue. If it only malfunctions when hot, it indicates clutch and lockup material that was once in the bottom of the pan when cold is now circulating through the transmission and causing a malfunction.
4. Smell the fluid. Even if the fluid is red, smell it. If it smells like a forest fire, you got owned.

Regardless, get the thing flushed on a regular basis once it's working again. Completely fluid change/flush the transmission and transfer case every 15-30k. Don't just drop the pan and change the filter, you're only replacing 4-5 of the 12 plus quarts still left elsewhere in the transmission.

Hope my babbling helped. Even if you can't fix it yourself, it's good to be armed with knowledge when you go to a shop so that you can catch them trying to pull a fast one before it happens. Best of luck to ya!