Continuing fixing on my high miles 98 Tahoe

[zidjan]

Hi guys,

still trying to address a few things on this old girl...

1. There's a fan like noise (flap flap flap) when I let go of the gas while in motion....I hope you guys know what I meant ...the sound goes away when I accelerate....it's coming from underneath the cabin....tranny, transfer case? the rig shifts fine and quite strong.

2. Everytime I turn the steering wheel full to the left or right...the rig hesitate to move .... it's like the car won't turn at all unless you give it some gas... sometimes I could turn the steering wheel all the way to the right or left and the car won't move at all....what's going on there? any idea?

Thanks guys

 

[lesterl]

1. Ujoint?

2. When is the last time you had a tune up?

 

[zidjan]

1. Ujoint?

2. When is the last time you had a tune up?

I bought the rig not too long ago and has been slowly fixing the little things and tuning it up....she's got high miles (215k) bought it real cheap and is going to be my towing vehicle....so far I had done:

1. New NGK plugs.
2. MFI conversion.
3. Tranny fluids and filter
4. rear diff fluids.
5. Front diff fluids.
6. Just did the transfer case fluids yesterday (I haven't check whether the sound went away).
7. thermostat and coolant
8. Oxygen sensors (threw off a Cel but fixed that)
9. new front shocks.
10. working on the ac now (not working) changed the actuator and brought back the vents .... trying to figure out leaks from the ac ...rig won't hold freon.
11. New dist cap and rotor and rotor gear.

So I took off the center console for cleaning ...when I drove the rig that' when I hear the flapping sound (much like you put a paper on a fan)...it's coming from underneath the center console.

I went underneath and there is a little play from the intermediate shaft? the shaft from the front diff to the transfer case...hence my suspicious words the Ujoint...i never diagnose a ujoint failure before so I am not sure.

 

[lesterl]

My rig has 297k on it, I bought it high mileage also but got a decent deal on it and put a pump in it.

I like the NGK plugs I put in mine, I have not done the MPFI conversion (still have poppets running strong...)

Also check for wires and hoses dragging the drive shaft, but you probably already did.

Get a jar of UV dye at the parts store, about $8 for a few ounces, but it is bright under UV, then get an injector (hose with a holder for the dye, yet another $8 or so), and if you have a UV light great, if not pick one up, IIRC they make a kit with all in it.... Charge the system with a little Freon and the dye, let it leak out over a couple days, then one fine night or if you have a dark garage, inspect lines and fittings with the UV light. Green is bad. Also a common leak point is the service ports, (I replace them ALL THE TIME) MT2901 is the part number for the service part kit (they wont be able to look it up properly, somehow it isn't in any of the parts stores systems around here, but they carry it.....

The front shaft should not turn unless you have 4wd engaged or your Tcase is stuck in 4wd.

 

[zidjan]

My rig has 297k on it, I bought it high mileage also but got a decent deal on it and put a pump in it.

I like the NGK plugs I put in mine, I have not done the MPFI conversion (still have poppets running strong...)

Also check for wires and hoses dragging the drive shaft, but you probably already did.

Get a jar of UV dye at the parts store, about $8 for a few ounces, but it is bright under UV, then get an injector (hose with a holder for the dye, yet another $8 or so), and if you have a UV light great, if not pick one up, IIRC they make a kit with all in it.... Charge the system with a little Freon and the dye, let it leak out over a couple days, then one fine night or if you have a dark garage, inspect lines and fittings with the UV light. Green is bad. Also a common leak point is the service ports, (I replace them ALL THE TIME) MT2901 is the part number for the service part kit (they wont be able to look it up properly, somehow it isn't in any of the parts stores systems around here, but they carry it.....

The front shaft should not turn unless you have 4wd engaged or your Tcase is stuck in 4wd.

I just pump some freon with dye in it last night...just bought UV light bulb also .. let's see if my eyes are good enough to detect the leak points.

the front shaft shouldn't turn huh while in 2d huh? hmmm... I can turn it ..what does that mean? how do I unstuck it from 4wd? actuator?

 

[lesterl]

If you can spin it then it is freewheeling and not engaged to the tcase or the front end, by the same token you CANT spin your main driveshaft because (hopefully) you have the wheels chocked and in park.

Was the dye UV? It will be relatively easy to spot.... the darker the better tho. Might check into the service port kit also, the high side the whole piece unscrews, the low side is a tire valve type made for Freon......

 

[zidjan]

If you can spin it then it is freewheeling and not engaged to the tcase or the front end, by the same token you CANT spin your main driveshaft because (hopefully) you have the wheels chocked and in park.

Was the dye UV? It will be relatively easy to spot.... the darker the better tho. Might check into the service port kit also, the high side the whole piece unscrews, the low side is a tire valve type made for Freon......

No the main driveshaft is unmovable ....the intermediate spins freely ....although I found out that because my 4wd controller broke ..so the car is always in 2wd..so I guess that makes sense?

Ok so the service port meaning the two high and low like in the pic? if those are leaking, what do you fix? I been seeing the ac service kit which includes a bunch of rubber o-rings....sorry I never had to deal with ac leakage before whole ac system seems really foreign to me.

 

[lesterl]

shafts sound good, and correct on the pic, most of my leaks are from either or both service ports that I have fixed. Ask for part #MT2901 it should have what you need to do the ports.

 

[zidjan]

shafts sound good, and correct on the pic, most of my leaks are from either or both service ports that I have fixed. Ask for part #MT2901 it should have what you need to do the ports.

Thank you...I'll do that once I get myself a UV light to confirm where the leak is after that unto the next issue