C6 trans tight

[ButterBall]

I have a 1984 with a 302 and a C6 trans. I changed the trans oil and cleaned the filter ( the oil looked and smelled bad, but the filter was clean). Changed the transfer case oil also.

Slowly over period of days of driving, the transmission began to feel tight, the Bronco did not want move forward as it used to, almost as if the brakes were holding it back (checked, they weren't). In reverse, it feels normal. In fact now I cannot drive in forward gear, but was able to go in reverse and park my truck.

I am not a diagnostician, but I think the tranny is sick. The question is to salvage this trans by repairing it or to find a used one. I wonder if a rebuild kit would fix it? How would I know? I am not afraid to tear it down, I am not a pro mechanic, but I did replace the rear axle bearings on both sides myself under a shade tree, I even figured out how to drain the torque converter myself( yes I did replace the bolt). So, now I am willing to tackle trans rebuild if thats what it takes.

What's your opinion?

Thanks for the help

 

[Bully Bob]

What was it doing B/4 the fluid change.....did something precipitate the fluid change...??

"------oil looked and smelled bad----"

This is prob. not a good sign.

Did you use the correct type of fluid..?

Auto trannies are not for the weak at heart ( to re-build that is...)

 

[ButterBall]

What was it doing B/4 the fluid change.....did something precipitate the fluid change...??

"------oil looked and smelled bad----"

This is prob. not a good sign.

Did you use the correct type of fluid..?

Auto trannies are not for the weak at heart ( to re-build that is...)

Well, I bought the truck used, 170,000 miles, I did not know when or if fluid had ever been changed.

Fluid was brownish, smelled "old". Don't know any other way to describe it. I replaced it with dexron/mercon III.

Prior to changing, the symptom was that at highway speeds, when I took my foot off the accelerator, truck would decelerate as if compression of engine was slowing it down, kind of like when a semi goes down a mountain road using engine braking to control speed. In other words, my Bronco did not coast and gradually decel. I felt this was not normal, I thought maybe trans need attention. If it didn't, it does now.

I thought I could pull the clutches out and what ever else, lay them out on a table and insert new parts in reverse order. I know that sounds simplified, I have never done it before, but I have learned to repair/replace many simple and and a few more technical items since I bought this truck.

Your opinion is valued, thank you for the reply, and if anyone else wants to weigh in, please do. I am grasping for straws at this point.

 

[mbtech2003]

how fast were u going my 95 when i'm going lets say 75 i have to keep the gas on if i lift off it completly it will slow fast. broncos are not arodynamic and will slow down fast on the highway. as for u changing the trans fluid, by removeing the old u flushed out most of the material in the fluid that was keeping the trans shifting and keeping the power down. i have seen it many times. transmissions that have over 150k miles on them with still the orignal fluid in them. the only way to keep them from not slipping is to just leave them be and not change the fluid. but because u changed the fluid it will most lickly have to be rebuilt /emoticons/[email protected] 2x" width="20" height="20" /> i would suggest bringing to trans shop. as u might not have all the special tools involved in removeing all the clutches ect... every thing in a transmission has to be at spec. for the tollerences. best of luck >-

 

[wtfdissux]

one quick idea is check the modulator and the vacuum line to the intake if it is broken or leaking (line) shifting will **** if the mod is bad may even be sending atf into the intake manifold this will cause even new fluid to get that not so healthy appearance and odor if both are good check fluid allow truck to run until warmed up put in neutral lock the park brake and check fluid level if you drained the convertor it takes a little to "refill"it and your fluid may have gone down as a result also on a c-6 the bands are adjustable but reverse uses the same band as first so you should have both not one or the other unless there is other problems(valve body shift pawl etc.) in any case cost wise it may be easier and cheaper to got junkyard shopping around here a rwd tranny is about $125.00 versus the rebuild kit tools and down time but if you want a confirmed "good" tranny call a tranny shop they might have one on the shelf that is already re-manned and comes with a warranty

 

[ButterBall]

I appreciate all the replies. Tools? Tolerance? getting deep. I found a web address where I can request a part, and it is sent to several salvage and reman. shops around the states. I have gotten several replies. Least expensive I found was $295+$100 shipping. 30day warranty, next was $425 total with 90 day warranty. They all say they have been cleaned, inspected, and found to be in working condition. I am leaning towards total replacement.

QUESTION: are all automatic 3spd C6's the same, or do I have to find a model/part number or ID? if so, where will I find it?

Oh, web address is www.uneedapart.com, incase anyone wanted to check it out.

 

[wtfdissux]

try junkyarddog.com

 

[ButterBall]

I will try them right now, thanks.

 

[Justshootme84]

YEah, I agree with ***'s advice. Before replacing or rebuilding the C-6, take a look at the vacuum line for the modulator valve. That's normally the cause of shifting problems. I can rebuild an engine in my sleep, but won't dare touch an automatic transmission. Leave it to the pro's is my advice. Check with 2 or 3 transmission shops about your problems. While 3 will say rebuild it, a competent one can often diagnose the problem and fix only what needs to be. The brown fluid and burnt odor is a bad sign, indicating excessive heat. IF the clutches are worn down, you will get alot of slippage, but normally will notice it. I have 3 C-6's with over 200K miles on 2 of them. Changing the fluid is often worse than leaving it alone. Check the pan for any metal filing or fragments, too. JSM84

 

[wtfdissux]

under statement on rebuilding an auto tranny was going to once till what I taught was a nice free catalog in the kit box turned out to be the directions was almost 1/8th inch thick printed on newsprint

no thanx same here on an engine or any thing else for that matter the harder the better I like challenges but that one is why tranny shops make the big bucks