Won't go above 35 mph

Russ

Original poster
Member
Jan 4, 2012
43
My daughter came home the other day and said her 2002 Trailblazer wouldn't go above 35 MPH. The service engine light was on, so I checked the codes. Got one that said the transmission was slipping. I checked the transmission fluid and it was WAY low! I filled the tranny with fluid and took it for a test drive. I had no problems getting it up to 45 MPH in the neighborhood.

Came home last night and said the car wouldn't go above 35 MPH again. Checked the codes again but all I got was P1482 (Fan clutch, fan clutch relay). Reading more about this, the article said it could affect Vehicle speed sensor, Transmission fluid temperature sensor.

Could this be causing her problem?

Thanks in advance.

Russ
 

Ed H

Member
Oct 18, 2012
167
I have no personal experience with the fan clutch (yet), but my money is on YES. I have read the fan clutch can cause numerous issues, and if it is throwing a code it needs to be replaced. At least yours is throwing a code. Many fail without a code.

Replacement is not bad after you remove the fan bolt from the waterpump. I highly recommend the following method. GET A CHAIN. I used the chain from my kids swings. Remove one bolt from the water pump pulley, insert throught a link on the chain, and then tighten back into place. Wrap chain around the wheel hoist bracket and secure. Now get a 1-7/16 open-end wrench of a large cresent wrench and loosen that big bolt. I had to use a breaker bar and a shitload of muscle. It was on there unbelieveably tight! Many 4-letter words. Once removed, it is downhill and very easy.

Drain a little coolant (use a siphon pump if you have one), remove upper radiator hose, remove 2 fan shroud bolts, disconnect fan clutch connector, then pull the entire fan / fan shroud up and out of the engine bay. It is an extremely tight fit getting it in / out. Once out, the clutch is held in place by a few bolts. No biggie. Remove, replace, and re-assemble. Use chain to tighten the fan bolt back onto the waterpump.

Good luck. If I had taken pics I would share... (Did this for waterpump replacement last weekend)...
 

triz

Member
Apr 22, 2013
746
Fastest and easiest way to remove the fan clutch without cursing is a air hammer with a small punch on it. I spent some time trying to get mine off and I almost passed out, no lie. Borrowed a air hammer and small punch and just got it on the edge and off it came. Less than 5 minutes.

Since the fan clutch might be bad you might as well replace the water pump since the fan clutch threads in there and if that goes bad then you have to do it all over again. I have a spare water pump from Napa that I can sell you if you go that route.
 

Menthol

Member
Dec 8, 2011
177
When my fan clutch was bad, I had one mechanic told me the transmission way bad. Do you hear the fan sound (sounds like a jet engine thrust in reverse)
 

gmcman

Member
Dec 12, 2011
4,656
Was the reduced Engine Power light on? How many miles on the vehicle, how many miles on the current trans fluid? What color is the trans fluid, does it smell burnt?

Good tips on the fan clutch removal, just keep in mind, if the pulley is giving or turning, then your torque to remove the large bolt is going to rotating the pulley....it needs to be secure. I used a pipe on the end of a large adjustable wrench to break the nut loose.

Not sure how the fan is connected to the trans aside from cooling but you definitely need to confirm fluid condition, and ask your daughter how long she was trying to get the vehicle above 35. Unfortunately you may have some burned up clutches but hopefully not.
 

triz

Member
Apr 22, 2013
746
If your using the air hammer you wont need to secure it. It will bust it loose. That's the quickest most painless way to take it off. Save yourself a hernia.
 

Russ

Original poster
Member
Jan 4, 2012
43
Replaced the fan clutch today. Took it for a ride and will now go above 35 MPH and no codes! But........not shifting correctly. :frown:

Guess she caused problems with the tranny letting the fluid get so low. Will take it in to have it checked. Anyone know how much a rebuilt tranny will cost? :lipsrsealed:

It just never stops but we both love this car!

Thanks everyone for the useful advice.

Russ
 

gmcman

Member
Dec 12, 2011
4,656
I would remove the trans pan and replace the filter, small chance it could be slightly clogged. Don't worry about the seal that comes with the filter just yet, if the filter takes some tugging to remove and presses in firmly then the seal should be fine for time being.

When you say it doesn't shift right what exactly is it doing? Delayed shifting or slow,lazy engagement?

Can you take a swipe of trans fluid on a napkin and post a pic, or white piece of paper?
 

Russ

Original poster
Member
Jan 4, 2012
43
gmcman said:
I would remove the trans pan and replace the filter, small chance it could be slightly clogged. Don't worry about the seal that comes with the filter just yet, if the filter takes some tugging to remove and presses in firmly then the seal should be fine for time being.

When you say it doesn't shift right what exactly is it doing? Delayed shifting or slow,lazy engagement?

Can you take a swipe of trans fluid on a napkin and post a pic, or white piece of paper?

The fluid is/was brown and smelled burnt. I had to add 4 qts to bring it up to where it should have been.

When it shifts at about 20MPH, it's fine but as the speed escalates, the engine revs and it doesn't always shift. I have to back off, let it slow down give it gas and then it revs high before shifting. As I said, when she first brought it home, it was showing codes that included transmission slipping. Was wondering if she wiped out some of the clutch packs.

Thanks for the replays

Russ
 

tricguy007

Member
Dec 7, 2011
131
Just find yourrself a low mile used one from as salvage yard CAR-PART.COM
 

gmcman

Member
Dec 12, 2011
4,656
I believe the trans could be temporarily band-aided with a fluid change and a vette servo to increase holding power in the 2-3 shift. Unfortunately the life expectancy has been seriously compromised IMO.

Do you plan on keeping it? I believe so based on what you told me so I would absolutely go with the repair since it would only be about 4-5 car payments on a new vehicle. You could easily find a lower mileage unit at any salvage yard or even the bay. If you can find one used with around 80-100K and the fluid has been changed, refreshing it would be a piece of cake since it's out of the vehicle.

New separator plate, PWM TCC clutch eliminator valve, new accumulator pistons, vette servo and these parts should all be less than $100.

A quality rebuilt trans you are in the neighborhood of $2000-2500 with a good torque converter, I would go with Edge.

The trans can be expensive if you go with a rebuilt unit but it's piece of mind and these transmissions are kinda cheap compared to the newer crop.

This is the trans I will likely go with when mine ever takes a dive. ProBuilt 4L60E
 

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