Ok here it goes. I just bought a 2000 Dodge Ram quad cab 4X4 sport with the offroad package (4.10 gears). Automatic trans and truck has 191K on it. Ran and drove just fine. I thought it would be a good idea to change fluids and filters on it so I opened up the rear end and replaced the fluid with no probems.
I dropped the trans pan and put a new filter in it...again no problems. I noticed a slight oil leak around the oil pan gasket so I dropped the pan and put a new gasket in. Everything all good at that point.

I then filled everything up and checked for leaks....no leaks. I did the check trans fluid in neutral and then went through the gears with my foot on the brake. Ive dont this a few times over the years without a problem.

I let it run for a bit and then went to take it for a test drive down the road. Well at the end of the driveway it died on me when I was going to take off. I started it back up and put it in drive....it kinda jerked then I took off. I drove down the road pretty slow. Id say like 30-40.

Truck just doesnt seem to have the power it did before. I dont know if its the trans or the rear end or both. Like I said it was fine before the new fluids and filter.

No check engine light on either. I stumped.

 

Knock something loose in the process?

Did you use gear oil with the friction modifier for the LSD that's in the rear?

Is the plenum fixed?

 

I've heard of this, that's why I haven't done my tranny filter change. some people on here will sat CHANGE THE OIL, but I don't want this happen to me. highly doubt it's the dif.

 

I used 75-90 synthetic for the rear. I cant see what I would knock loose on just changing fluids/filters.

I havent a clue if the plenum was done. It ran and drove perfect before all of this. I mean no codes no leaks...very strange.

 

Rear still needs the friction modifier. Read the bottle, might already be in there. if it isn't, you NEED to add it.

Have a look down your throttle body, see any oil pooling in there?

Might try resetting the PCM..... see if that makes any difference.

 

I thought the synthetic had the friction modifier in it. Im not 100% on that but thought it did. I bought the walmart brand 75-90 synthetic gear lube. Ill check the plenum. Kinda odd that it would go out all of a sudden. work perfect one day and crap the next.

 

Probably coincidence...... How old are your O2 sensors?

Verify your gear lube has it. If you still have the bottle, should say right on it.

 

i checked the bottle.....doesnt say anything about having friction modifier in it. My bad on that one.

i havent a clue to how old the O2 sensors are seeing i just got the truck a couple weeks ago.

 

how much friction modifier goes in it anyways?

for some reason I thought the 4.10 anti spin rear was like a posi........or the opposite of the one wheel wonder like my other truck with 3.55's

 

erm... not sure. Grab the 01 service manual from the Service manual thread in the faq section. It's in there.

Replace your front O2 sensor at any rate. It's probably original. (do it at the same time you do the plenum.)

It is. It's a clutch-style limited slip. Hence, the need for the friction modifier. If it isn't working, might need a rebuild. (they weren't the best when new....)