2000 Jimmy 4.3 4x4 issues

Hi guys i am having an issue with my 2000 GMC Jimmy 4x4 i have recently replaced the radiator, alternator, thermostat, battery.

Before changing the radiator i had a very minor leak and would only leak when driving while pressure was built up but i would notice if i drove for an extended period of time like on the interstate and then got off at an exit and stopped then started going again my transmission would hesitate from 1st to 2nd and then be really hard into the next gear. It didnt happen all the time only 4 times in like a 2 month span. (and i drive interstate daily 50miles to work)

It completely stopped doing the hesitation but now when driving it on the interstate it really doesnt want to go over 60mph it shifts through all the first gears clean as a whistle but when i get up to speed on the highway or go up a hill it seems to lose all power will rev up to 3500rpm and not shift into the final gear. I can let my foot off the gas and it feels like it shifts but i think it is just locking in the last gear because i will get no speed gain from it if i hit the gas afterwards it just revs up again and holds.

Now i have been driving it like that for sometime (i know just been to broke to do anything about it). a couple days ago i was finally able to change out the radiator and it seemed to go fine except i couldnt get the bottom shroud back on with the new radiator seemed like the radiator was slightly smaller then the shroud could fit in so i just took it out.

Now i have a transmission fluid leak when i drive it and it sprays my whole passenger wheel well and then drips from right under where the radiator is on the passenger side.

I think i may have knocked something lose while changing the radiator.

Anyway sorry for the long post i figured background info was useful

My questions are : Any suggestions as to where the leak may be coming from? I checked all hoses i messed with while doing the radiator and they seem ok.

Also what is causing my truck to not shift at high speeds?

also forgot to mention when i crank it it has a loud noise coming from the bottom of the vehicle (i cant pinpoint where) that sounds like a can of shrapnel being shaken and its a sound that is always present when i first start the vehicle but then it dies out if i drive for a while.

Thanks!

Hi guys i am having an issue with my 2000 GMC Jimmy 4x4 i have recently replaced the radiator, alternator, thermostat, battery.

Before changing the radiator i had a very minor leak and would only leak when driving while pressure was built up but i would notice if i drove for an extended period of time like on the interstate and then got off at an exit and stopped then started going again my transmission would hesitate from ST to 2nd and then be really hard into the next gear. It didnt happen all the time only 4 times in like a 2 month span. (and i drive interstate daily 50miles to work)

It completely stopped doing the hesitation but now when driving it on the interstate it really doesnt want to go over 60mph it shifts through all the first gears clean as a whistle but when i get up to speed on the highway or go up a hill it seems to lose all power will rev up to 3500rpm and not shift into the final gear. I can let my foot off the gas and it feels like it shifts but i think it is just locking in the last gear because i will get no speed gain from it if i hit the gas afterwards it just revs up again and holds.

Now i have been driving it like that for sometime (i know just been to broke to do anything about it). a couple days ago i was finally able to change out the radiator and it seemed to go fine except i couldnt get the bottom shroud back on with the new radiator seemed like the radiator was slightly smaller then the shroud could fit in so i just took it out.

Now i have a transmission fluid leak when i drive it and it sprays my whole passenger wheel well and then drips from right under where the radiator is on the passenger side.

I think i may have knocked something lose while changing the radiator.

Anyway sorry for the long post i figured background info was useful

My questions are : Any suggestions as to where the leak may be coming from? I checked all hoses i messed with while doing the radiator and they seem ok.

Also what is causing my truck to not shift at high speeds?

also forgot to mention when i crank it it has a loud noise coming from the bottom of the vehicle (i cant pinpoint where) that sounds like a can of shrapnel being shaken and its a sound that is always present when i first start the vehicle but then it dies out if i drive for a while.

Thanks!

Transmission fluid leakage and transmission not shifting right points to transmission damage from running low on fluid.

As to the leak you need to look for where the leak is coming from.
Check the cooler lines and fittings from rad back to transmission.

As to transmission shifting problems a good transmission capable scanner will tell you a lot about the transmission.
As to the noise without hearing it or checking it out we can not help.
First pinpoint where the noise is coming from.

Ok an bit of an update. I took it to autozone and had them check my engine light code. It didnt bring anything back about the transmission but instead it gave this error Catalyst System Below Efficiency. Would a bad cat cause problems with acceleration? I am fairly sure that is what the noise is now as well. Any comments?

Ok an bit of an update. I took it to autozone and had them check my engine light code. It didnt bring anything back about the transmission but instead it gave this error Catalyst System Below Efficiency. Would a bad cat cause problems with acceleration? I am fairly sure that is what the noise is now as well. Any comments?
Cat codes do not say bad cat only that it is not working right.
We need code no and other engine sensor readings?
But.
Yes a bad cat can cause engine running problems and also if engine is not running right it can cause transmission shifting problems.
The engine has to be running good for the transmission to shift good.

But just a cat code can be caused by other things besides cat.
What was the code no?
Where the transmission has been run low on fluid it needs tested on a transmission capable scanner for problems and also you need to find the leak.

You also need to do some proper testing not just a AZ code check.

Ok another update.

I had the tranny tested and it is ok. I also had the Cat checked and it is indeed in need of replacing. They quoted me $850 to replace it which i cannot afford. So i was considering changing it myself, how difficult of a job is this? I have done quite a few of repairs on my car (radiator, alternator, belts,) simple stuff. Also i was hoping it would not be to hard to put one of the cheaper universal high flows on it instead since they are much cheaper This One. (http://www.amazon.com/Magnaflow-91005-Universal-Catalytic-Converter/dp/B000COPBPI/ref=au_pf_ss_1?ie=UTF8&Model=Jimmy%7C529&n=15684181&s=automotive&Make=GMC%7C48&Year=2000%7C2000&carId=001)
It seems from what i have read it is as simple as unbolting one and bolting in another. Is it that simple with the universal one? Is there modding or extra piping or anything needed?

Thanks for any insight.

Ok another update.

I had the tranny tested and it is ok. I also had the Cat checked and it is indeed in need of replacing. They quoted me $850 to replace it which i cannot afford. So i was considering changing it myself, how difficult of a job is this? I have done quite a few of repairs on my car (radiator, alternator, belts,) simple stuff. Also i was hoping it would not be to hard to put one of the cheaper universal high flows on it instead since they are much cheaper This One. (http://www.amazon.com/Magnaflow-91005-Universal-Catalytic-Converter/dp/B000COPBPI/ref=au_pf_ss_1?ie=UTF8&Model=Jimmy%7C529&n=15684181&s=automotive&Make=GMC%7C48&Year=2000%7C2000&carId=001)
It seems from what i have read it is as simple as unbolting one and bolting in another. Is it that simple with the universal one? Is there modding or extra piping or anything needed?

Thanks for any insight.

Buying cheap cats will give you cheap cats that do not work up to par.
And have to be weled on.

If you want one to unbolt and bolt on and work good you need to stay with a good brand direct fit.

Check out what your good local parts place has in direct fit setups.

Also when you take off old ones thake them to a metal salvage place and sell them.
Some bring 75-125 US $ or more.

Yeh i understand that buying a cheap part will get me cheap results. I am only trying to make this vehicle last me another 6 months and then i will be able to buy me a new one. It has 190,000 miles on it i just cant justify spending another $1000 dollars on it since i have already spent $2000 on it in the last 7 months. I am just trying to find the cheapest way to get it to last me another 6 months. So the universal one does require welding? I was afraid of that because the cheapest direct fit i can find is $300 - $400

Try shopping around at different muffler shops. I just replaced the cat AND muffler on my 2000 Jimmy SLE 4.3L 2WD for $250.00 plus tax INSTALLED. Yes they welded it on. The cat alone without the muffler would have been $185.00 installed.

Some may say it is/was an el cheepo, but I don't think so, as this is a reputable muffler shop that has stayed in business for decades. Running great now for a week and no codes. Remember, you're only looking for 6 months.