Auto Transmission question.

[Idually]

I want to thank those who responded to my first post about tire sizes. I do appreciate it.



Now on to more fun stuff... It's 5:30am, and a bit chilly. I climb into the truck, fire it up with a flick of the key. Sit for few minutes to let the fluids flow around, pull the shifter into Reverse and hear (what I might call) a "hiss" of sorts. Takes a moment (small moment mind you) for the transmission to "grab". It's sort of a gentle grab though. My thinking is that fluids haven't moved about enough yet. Back out of the drive, and hit the "D"... Seems to be "sluggish" just abit, but I'm just idling forward (I think the pump has been turned a bit, because the idle is high) letting the engine "warm" itself up, and take off for work. A mile or two of "slow" streets taking it easy heading for the highway. Jump on the highway up to "operating temp" and we are good to go! 30 minutes later, I pull into the parking lot at work and set up to back in to my favorite spot, pull it into "R"... momentary delay and "thump"! Not a "bang", but a low thump. OOps... not centered... so back into "D". another momentary delay another "thump". Are you getting the pic yet?



If not, here is my feeling. Cold=A bit sluggish(plus hiss in "R"). . OpTemp (After 15 miles) a "thump" when shifting.



I'm not sure it's "bad", but I can't be "good". What do you guys think? A simple transmission service and filter?( ATFluid appears to be in good shape). Idle TOO high? (No Tach. . YET... ). Normal?(I think not)



In short, I'm a bit concerned. It's an A-518 trans with OD. I haven't owned a truck like this before but I want this truck to be right, for a very long time. I love it. Just trying to avoid surprises.



Any thoughts? Thanks in advance.



Andrew

 

[cguthrie]

I get that thump to sometimes but it's usually when i first start the pickup. I don't know if it should really concern you or not. With that many miles on it though i wouldn't really worry about it. The 1st owner of my truck got the trans. rebuilt at 70,000. You might try the trans. service and get the bands adjusted. See how that works for you. You should really get a tach and see how high that idle is. I can't remember what it is supposed to be but someone will jump in here and tell you. BTW lets get some pics of that dually in the readers rigs. i would like to see it.



Chris

 

[hdm48]

IDually, the hiss raises some red flags. It sounds like a leak at the valve body. Worse case scenario, a clutch pack. But I would lean more towards the valvebody. What I would do first is, give it a service. At this time you should torque the valvebody bolts.

The thump you hear may be a late ingagement due to the fluid loss at the valvebody.

If the transmission has ever been overheated, this will explain the loose bolts.



good luck







Dave

 

[Idually]

Thanks again. I forgot to mention that the truck does have an Aux trans cooler under the bed. Does that change things?



Knowing the little that I do about the auto trans, I suppose the Valve body makes some sense, As does the bands. How difficult is it to do a trans service(filter, bands, fluid) by myself?



I bought this truck in April '03. I did as much research on it as I could to verify the mileage. I believe it is accurate, but there are things about it that make me think it is not. I'm the third owner. The first owner had it for the first nine. The Second, only 6 months. It really runs fantastic and is getting 17-18 mpg. Starts with flick of the key. Doesn't smoke or use oil.



Does anybody know if Carfax can be fooled?



Thanks in advance.



Andrew

 

[jdurham]

Does anybody know if Carfax can be fooled?

Yes they can. I helped a friend rebuild his car after a wreck, turns out it was the third accident, and there were some more minor accidents in there as well. The car has 225,000 miles on it. Since he is the original owner, and didn't report his accidents (mostly off road excursions by coming into a corner too hot on the street or on the track) the carfax is clean on this car. Also, we replaced the dash becuase of cracks, and the speedo he got (but didn't use) said 79,XXX miles. We could've easily plugged it in, and after the car was painted, passed it off for an 80K mile car. Many things you have to see for yourself, as Carfax doesn't always know...



Jim

 

[cerberusiam]

Doesn't sound like anything unusual but we all know how accurate diagnostics over the internet are. At any temp less than 40 degrees I always put the trans in neutral and let the truck idle for at least 5 minutes before taking off. The fluid does not circulate thru the coolers and rest of trans until the trans is engaged in neutral or a gear. The hiss sounds about right if you went to reverse from park with no warm up. As long as it dissappears after everything is warm I wouldn't be too concerned. The thump is pretty much normal and accentuated with a high idle. A metal sounding clank would indicate a rearend or driveline problem but the thump will happen frequently when going from forward to reverse or the other way. I am pretty sure its just the slack being taken out of clutch packs, gears, etc in the trans. Sluggish acting and weird noises is pretty usual at low temps and no warm up on an auto. These trans are really nothing more than a 727 with an OD and thats pretty much what every one I have owned has acted like. If the trans shifts well and there is no noise at highway speeds with the amount of miles on it you should not have many problems. Tomorrow it may quit but thats an auto. I have 270k on the same trans with 3/4 of that mileage being towing a big 5'er and horse trailers. I am pushing 260 HP and have abused it a little so the trans is starting to show wear. The biggest weak point will be the OD as it is a little undersized. Normally you will get noise at highway speeds or a low growl when coming to a stop that signals impending problems. Try warming the trans before taking off and back the idle down and see if that makes a difference in the way it acts and the shifting thimps. Good luck.

 

[Idually]

Once again, Thanks



cerberusiam. That makes me feel quite a bit better. I think I'm adjusting to this truck. Not only is it my first diesel, but it is the largest truck that I have owned to date. I tend to "baby" it. Maybe I should be pushing it a bit more often, as this truck seems to like it when I do.



As far as Carfax goes, that is what I figured. Worries me a little, but maybe when I get some pics up in tha gallery I'll do a "Poll" and see what you all think.



Thanks. I'm sure I'll have more questions. I just wish I could give some answers, to pay you all back!



Andrew

 

[hdm48]

Andrew, fill out your signiture so whenever you have an issue we can know what truck you're driving. This will help us give a quicker responce.





Dave

 

[Idually]

I did my sig last might before this post. It appears in the first post, but not my response. Hmmm? I'll try to fix it.



Andrew

 

[BushWakr - RIP]

Your signature will show on the first post you make in a thread, after that it defaults to "do not show".

The reason being is, it saves on the memory and bandwidth of the site.

If you want to show it again in a thread you need to select "show signature" at the end of the "post reply" page, down near the bottom.



bob.

 

[Idually]

Thanks B. W. I understand. I noticed that "box" and it has been checked on my replies (as it is right now). Not sure.



Andrew