Engine/Transmission (1994 - 1998) running good untill 300001

[grass hopper]

well i was on my way back from a swap meet here in texas with a friend of mine (he is looking into buying a CTD) and we were talking about just how good my truck runs as it just turned 300000.

we get to about 300001 then all of a sudden it starts to shutter real bad. were doing about 79mph going up a small hill. we get to the top and it go's away. then i try and make it do it again with no luck about 5miles down the road i try to make it do it again and it does. i look at my boost gauge and it low the egt's are low water temp is fine, oil gauge good. so i get back to the shop open the hood to see if i can see any thing and there is a small bit of water at the head under the therm housing. (not coming from the housing but on the head gasket) (was not low on coolent). could i have just blown the head gasket at the #1 piston? or do ya think i have a fuel filter going out?

any help on this would be nice. if it is a head gasket how hard is it to replace.

oh one more thing some time ago it started to do some thing weird AT 80 mph it would shift out of O. D then go back into O. D what could that be?

 

[rrausch]

Shifting in and out of OD is somewhat common and a few fixes have been developed. 1--clean the TPS with some sort of electrical contact cleaner, operating the throttle while you do so. 2--sometimes "electrical noise" in the wiring harness has been the culprit. Separating out the proper small wire and allowing it to lay outside the harness seems to work. Maybe someone can chime in here and tell you which wire that is for your truck.



As far as the shuddering, do you think it was your TC slipping? Or did it feel like the engine? I ask about the TC because you mention you were going up a hill when it happened.

 

[Howard Durand]

It really does sound like the TC clutch.



How long since the transmission was serviced?



Have you checked your transmission fluid lately?



At 80 mph you should have good pressure to keep the TC clutch engaged so you might want to take it to a reliable transmission shop and have some pressure checks done.

 

[JoeBioDiesel]

If the boost and EGTs are low I would suspect a fuel problem before I suspected the transmission. Check for fuel leaks, a plugged filter and air getting into the fuel supply line.



Joe

 

[grass hopper]

O. K this morning i got up to come into the shop. i start up the truck let it warm up for about 5min. then head into work. i get onto the freeway get up to 80 mph punch it and it takes off like a rocket 37lb of boost and would keep going if i let it. try this a few times no problems. could the turbo have been to hot last night. i did drive nonstop from Dallas to longview to Austin about 300 mile at 80 to 90 mph the whole way. the water temp was at about 185, the EGT was about 900, trany temp was at 125.



the trany was rebuilt 10 month ago and i have changed the fluid & the filter in it about 4 months ago. i did check the fluid and it was fine. a little over the full make but not to much.



i will clean the TPS today and see if it helps with the shifting in and out.

but as for the shuttering i will see if it starts to do it again. maybe the trany was to hot? the trany temp was rading 125* untill i stoped then it got up to 150*. but that was after the shuttering. I will take some pixs of the head gasket that i think mite be the problem and post them. that mite help with the diagnosis of what's coming out of the head.



could a blowen head gasket at the #1 piston lower the boost and power?

 

[DMC]

Grasshopper:



Try spraying the slicone based Liquid Wrench (Blue can) on the throttle return spring, above the TPS. Others have used WD40 also. This worked for me. Also check the plug under the TPS, and make sure the contacts aren't corroded. One other thing be sure the brake light switch is firmly against the brake pedal.



Did I correctly decipher that you got 290K out of the original transmission?



Have you considered the possibility of a vacuum occuring in your fuel tank, due to the long run. Could it be a vent issue?



Good Luck



Don

 

[Rhondasway]

I have a little more experience with head gaskets than I care to... I believe you could be losing boost if you blew the gasket. I'd be careful how much stress you put on it, because you could make it worse. If your oil makes it's way into your water, you'll have a gooey mess on your hands (for weeks), and could get stranded really quickly. I understand that water in your oil can damage your turbo.

Have you run it and stood there watching to see if the water is flowing out? Have you checked your oil for water and water for oil?

Have you ever replaced the head gasket? If you need to do it, don't be afraid to take it on; it's not that tough. Be sure that once you have the head off, take it to a good machine shop and have it checked and possibly decked. If the head needs to be decked, you may want to consider a thicker head gasket. Be sure that the shop does not use a belt for shaving the head; it must be machined to be done properly.

Also make sure your block is flat and clean, clean your bolt holes, and go ahead and replace your bolts (cheap insurance if your others are old). This is a great time to replace the infamous fuel return line (rubber) that goes bad and is a bear to access normally. It sits right under the head and takes about a minute to replace with no head in the way. Also do your fuel filter.

Don't forget that you have a pre-filter too, and that is commonly overlooked. They can get really clogged, so it's just a good idea to clean it.

I'm sure it's your TPS causing your truck to "hunt". Cleaning it is the most preferable means of fixing, 'cause they ain't cheap!

Was that long-winded enough? Let us know how it comes out.

 

[grass hopper]

i got some cleaner to clean my TPS. will do that today and see were it get's me. as for the head i will try and post some pixs right now.

o. k i have resized my pixs but it still will not take it. if some one would like to post these for me i can send them a e-mail with the pixs and they can post them for me.

thanks

 

[DMC]

How is it going Grasshopper?



Don

 

[grass hopper]

DMC

well so far so good. but i still think the head gasket is leaking water out of the side. i tryed to post up some pixs but it would not let me.