Hi, I have a 2000 Chevy Blazer 4DSD. For the most part it was a very good truck, never had any problems with it. I use it mainly to tow my pop-up camper and long trips. Due to all the state to state trips and the vehicle being in pretty decent shape I replaced the tranny about 6 mths ago.

Suddenly the truck became tempermental and when it rains it doesn't want to start and if it does and you go the distance it loses power. I will go from 55 mph to 20 mph in a matter of seconds. I don't know what to do.

Can someone please help. Thanks

 

Being that the 4L60e is electronic, the first thing to always check is a proper ground to the chassis. Then check the plug going into the Transmission - may need some wire dryer on it. It's on the passenger about mid-way, over the lip, along the pan.

Is it gearing down on you? Slipping? Why is it dropping speed? Spark related?

When they rebuild your trans, did they set it up for towing... This is extremely important on the Vortec V6(250 lb/ft+ of Torque) and the heavy weight(4800+ lbs) equipped Blazers. These Blazers came with basically a "car" transmission. Not a heavier duty truck trans - Oversight!

 

i wouldn't say these trucks came with a car equiped trany Travis, mines holding up quite fine, and i haul around a 20' car trailer without any issues, for the past 2 1/2 years anyways. plus any of the other heavy stuff i've hauled to the wreckers.

mind you, mine did come with the factory tow package.

as for the OP's issue, it sounds more like a bad cat. is the cat original? you don't mention what your mileage on the truck is either, but given the age, & the fact that the exhaust was removed when they rebuilt the trans (they could have dropped the y-pipe & cat, breaking he material in the cat), it could be just that.

how far down the road does it take for the truck to lose power & slow down?

as for the not wanting to start in the wet weather.......are you sure it only happens in the rain, or is it in any damp weather? when was the last tune up done? how are the connectors @ your ECM & distributor-clean, tight & dry?

 

Basically a Carpice/Roadmaster tranny. Just going by what my Tranny guy let me in on. Smallest GM 2-4 servo, plastic accumulators, etc. Corvette servo and pinless accumulators are a must - Along with a beast reaction sun shell.

Just saying.

 

I can never bad mouth the 4L60E in my Blazer 4x4. I burned the tranny so bad the fluid was black & blowing out the Vent tube for 70 miles. After a couple of flushing's & filter changes along with some Lucas tranny additive & later some LubeGard & a B&M SuperCooler that same tranny now has 158,000 miles & running strong. The burning was 75,000 miles ago.
As for the power loss. Check your plug wires. One easy way is go out at night & lift the hood & see if they light up with sparking.

 

It was in 'Vettes, Suburbans, GM 1/2 and 3/4 ton trucks, vans, Yukons, Tahoes, and SSRs, in fact in was in GM trucks a year before it was in a car. So, no, not just a 'car transmission'.