Tranny issues?

Recently a strange humming noise/whine has been coming from somewhere beneath my truck (the crewcab) and I'm not sure what it is. It sounds like metal scraping on metal, and it only occurs when applying power (i.e. not when coasting). It has been speculated that it is my tranny but it seems to be functioning normaly. I put some of the magic Lucas stuff in it and did not affect the noise at all. The noise is unbearably loud and doesnt seem like its going to go away on its own so anyone have any ideas on things to look for or cheap items to try replacing? The truck has 170k on it and has a 4L80E 4 speed auto tranny. Its possible that this is the original tranny in the truck, and if thats the case it has had a long, hard life.

I would change the fluid and filter first off.

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Originally Posted by afroman006

Recently a strange humming noise/whine has been coming from somewhere beneath my truck (the crewcab) and I'm not sure what it is. It sounds like metal scraping on metal, and it only occurs when applying power (i.e. not when coasting). It has been speculated that it is my tranny but it seems to be functioning normaly. I put some of the magic Lucas stuff in it and did not affect the noise at all. The noise is unbearably loud and doesnt seem like its going to go away on its own so anyone have any ideas on things to look for or cheap items to try replacing? The truck has 170k on it and has a 4L80E 4 speed auto tranny. Its possible that this is the original tranny in the truck, and if thats the case it has had a long, hard life.

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Kinda sounds like a u-joint or the drive line bearing

PS always check the easy stuff first.

does your truck have a drive shaft support bearing? Im drawing a blank on the name of it, :rolleyes: but it does around the driveshaft and mounts to the frame. mine went out in my truck and it did the same thing just before it ripped itself apart.

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Originally Posted by StevenAg03

does your truck have a drive shaft support bearing? Im drawing a blank on the name of it, :rolleyes: but it does around the driveshaft and mounts to the frame. mine went out in my truck and it did the same thing just before it ripped itself apart.

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the carrier bearing, when riding in it this weekend it sounded like a u-joint from when you were shifting from park to reverse, so go with those 2 options first, may be an easy fix that way

Yes it has a center support bearing (thats what they call it at the parts store, I'd always heard it called a pillow block but they looked at me like I was retarded when I asked for one). It has a decent klunk when shifting into gear so I'll check the u-joints and support bearing tomorow. I figured if it was them there would be some vibration but hopefully it is just them.

parts store monkeys usually look at you weird when you use the right name for something. it actually is a pillow block, just not in the automotive world. carrier bearing is what ive always known them by.

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Originally Posted by fbronco86

Kinda sounds like a u-joint or the drive line bearing

PS always check the easy stuff first.

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yeah, we did this once with my blazer. I thought the detroit was making noises. Took of the rear drive shaft and one of the u-joints was toast.

I'm not sure if obs chevy's are like the new one's where the front driveshaft spins all the time? Maybe slop in the chain on the t-case? I doubt it'd be worn c.v.'s, but driving home in 4 low can do some wierd things. But like everyone has said, could be the u-joints.

Edit- Again on the t-case, I had problems with mine when in 4hi/low, turned out it was the same problem that Grayson talked about below.

well, when mine made a crap load of noise about a year ago it was the snap ring on the rear output of the t-case that let go. this piece of shot part cost me a grand to rebuild the case. W/ no snap ring the t-case chain decide to slap the the planetary gears and wreck havoc on all the internals. Mine made noise while accelrating and got real bad after a hundred miles.

Well I took all 8 feet of rear driveshaft out today and the u-joints are fine and the center support bearing appears to be ok so I put them back in. The rear pinion seemed like it might have some excessive slop in it though, so I drained the diff and didnt notice any metal shavings or anything out of place. So all in all, my 2 hours of work turned up nothing...

I think I will change the tranny filter and fluid tomorow as well as the t-case fluid.

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Originally Posted by Doug Krebs

yeah, we did this once with my blazer. I thought the detroit was making noises. Took of the rear drive shaft and one of the u-joints was toast.

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Gas Tank spring break trip?

pillow block is that thing you have to draw in introductory cad classes

my f150 was a carrier bearing according to horeillys

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Originally Posted by robertf03

pillow block is that thing you have to draw in introductory cad classes.

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i guess they all do that, huh?

yup

you can always drop it off at John's Transmission and get it rebuilt for a lowlow friend price of $1700 :(

on the other hand, he's a really nice guy, answers his phone at all hours (11pm friday), really seems to know his shiat, runs a really tight shop and is very proud of it (came up on a saturday morning and made me take the half hour tour)

I'm prety sure the t-case is the source of the noise. I am going to start looking for a whole new case to swap in, I dont really feel like tearing the current one apart and then hunting down whatever parts are fukt up. I first need to figure out what case it has, its some kind of Borg Warner aluminum unit with a PTO cover on the side but thats all I know about it.

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Originally Posted by uglyota

you can always drop it off at John's Transmission and get it rebuilt for a lowlow friend price of $1700 :(

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no way its that much. he quoted me $1100 for a rebuilt 4l60e and that was using his core.

didn't he do your 700r4? What did that cost?
He quoted me $1600-$1700 "out the door" to do mine. I dropped the truck off Saturday.

Check the snap ring on the t-case main shaft

I aint checkin shiat. It oughta be done tomorrow. I will be very happy if it lasts me another hard year or so and then I'll see how I like wheelin an auto and figure out if a 300 really does bolt right up

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Originally Posted by uglyota

didn't he do your 700r4? What did that cost?
He quoted me $1600-$1700 "out the door" to do mine. I dropped the truck off Saturday.

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i did the R&R. ran me somewhere around $700, but i let him keep the other 2wd core. so that knocked a little off.


and, yes, i hear a 300 will bolt to a np241/208 adapter.

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Originally Posted by agjohn02

and, yes, i hear a 300 will bolt to a np241/208 adapter.

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i think you have to drill a couple new holes, but otherwise, it will bolt up where a 208 was

spline count is still different

only the jeep 208 and some dodge 208's had the same splines as far as I know.

ah yes, you have to get a new input for the 300 from novak. 27 spline. ~$185.

advance calls it a center support bearing

so I picked it up last night. John's a freakin cool guy. Or bored. Either way, he will talk your ear off about transmissions. He said he "built it up a little" because I told him I do a lot of towing. He got way over my head real quick but I did catch that he replaced my sun gear shell with "the beast" sun gear shell, which is hella bigger than the stock one. He said he removed the "corvette servo that makes it slam second" and even without it whatever he did to it makes this thing slam second like it never has before. Put a slightly higher torque converter in and took me for a ride to teach me about lockup. He might have seen me coming but I'm pretty confident his build will treat me well

did he tell you about putting somethingorother on the lathe and machining it out a little, like he does the all the game warden and police trucks. he gets rid of some kind of electronic shift control and makes it mechanical. my tahoe shifted harder after he got done with it. i was talking to him about "the beast" the other day and he said he's never seen one come back broken.

Would you go as far to say that John's Transmissions is to rebuild shops as Coco Loco is to Mexican food restaraunts?

I think the price point kills that analogy.

yeah john he showed me his lathe and chuck, but I didn't really understand what he did with it so I didn't mention it. I think he makes the pump bigger

my sun gear shell was in a few pieces, so I guess "the beast" was a good idea.

wish I had brought my camera to take a picture of the pile of parts. I toasted everything :D

Turns out it was the rear end. When I took the diff cover off and checked the pinion I forgot to check the carrier bearings. According to the guy at J&P Standard Transmission my carrier bearings went bad, which killed the pinion bearings, which chewed up the gears and caused the whining noise. I'm not terribly suprised with how many hard miles the truck has on it. It was $670 out the door which isnt too bad especially considering they got it all done in a single day.