So I think my TH350 is FUBAR

[rough69]

Well I think it is time for me to face the facts and pull the trans tomorrow. What do y'all think?

When I got the truck running it made a really high pitched whine like a gear drive was installed on the truck, but I figured it was the water pump / alternator as both accesories were old and sat around for a while.

Well I replaced both (the WP bearing was pretty bad), got the truck running well and even fixed the brakes (sweet!).

But the whine is still there but now it seems to go away after the truck warms up a bit and the truck has always had a whine when it is shut off that sounds like a jet engine slowing down (errrrrrrr stop).

Now that I can actually drive this thing, I noticed that it does go into all gears, but Reverse takes a few seconds to engage sometimes AND upon acceleration makes the truck shudder real bad.

Also, I know for a fact that the truck, when engaged in reverse, is NOT supposed to roll forward and it rolled a bit down my driveway (which is steep) while in reverse until I gave it some gas.

AND Freeway speeds seem impossible!

I mean I don't know what gears are in this truck (they feel like 4.11's?) or where to look for a ratio, but it seems like the truck won't do over 50MPH in third, but the motor sounds like it is doing ~3000RPM+ and going 100MPH.

Truck is a '69 C10 SWB 350, short shaft TH350, just had the driveshaft fully rebuilt with spicer universals and a new carrier bearing.

[krue]

I would at least drop the pan and check for metal before I pulled the tranny.

[68C15]

Originally Posted by krue

I would at least drop the pan and check for metal before I pulled the tranny.

waste of time that would be. (now I sound like Yoda)

the whining is the pump being severly worn out. the :errrrrrr,stop" sounds like a sprag clutch gone sour. the reverse thing is an indicator that the clutches are real bad and the piston seals are done. (reverse always goes first due to it needing the highest volume of fluid)

most tranny shops will do a bench job TH350 for around $400.

[Longhorn Man]

however, the truck can easily roll forward in reverse, on a steep driveway.
I've had 2 fresh rebuilt Th350's, and 3 well worn ones, and they all did this.

I agree with 68C15 1oo% That sucker is a gonner, but the jet turbine sound would be neet to screw with someone's head.

[woodridge]

I've heard many converters sound like that when they blow a thrust washer or spragg, it can also cause the rpm problem, they go from torque converter to fluid coupling.

[LockDoc]

-
If you're not sure what ratio your rear axle is there is a code stamped into the axle tube (see pics) and you can go here and look it up in the "axle" section. If your truck originally came with a six cyl it probably would have had a lower geared rear end.

http://www.americanclassic.com/paint.htm

LockDoc

[Lemield]

My 70 C20 has a TH-400 but it had a whining noise like you describe. I thought I needed a new tranny too. I decided to drop the pan and do a filter and fluid change. I guess the filter was clogged because with a new filter and fluid, it makes no noise and works great.....I probably just got lucky but it's worth trying. IMHO.

[rough69]

I forgot to mention earlier that I had done a complete fluid + filter change on the transmission prior to me driving it at all.

Now I take it that I also have a 4.11 rear as I suspected (thanks LockDoc!) but I have a 1970 rear instead of a 1969 I guess as the code is "TDB 0210".

Originally Posted by Longhorn Man

the jet turbine sound would be neet to screw with someone's head.

It definitely screwed with my head...

[mnunn454]

Sounds to me like a bad converter or it's very low on fluid.

Either s/b an easy fix.

[rough69]

It has the right amount of fluid in it still although the lines do leak so I ordered new ones that will be here next week.

I think it is entirely possible that the P.O. installed a new converter incorrectly as it is blue and has a drain plug on it upon further inspection.

I'm going to pull the trans, get it redone and pick up a new converter (think I'll get a 2000 stall B&M like on my old truck), install it with the new lines and pray for the best!

[trkklr77]

wtf? a drain plug on the converter!!!??!?

4.11 and 28" is 3000 at 50

the slow ingaugement and shuttering certainly sound like its dieing.

the reverse roll is nothing.

p/o could have installed a stall converter too, makes it spin to a higher rpm before it fully locks in. does the motor have a big cam?


if it was installed wrong it would have bent the flexplate and broke the fluid pump drive.

depending on where you live in cali, i have a 2wd th350 you can have to rebuild so yours isnt down extra time.

you do know it takes somthing like 10-12q to refill and empty tranny right?

[GREASEMONKEY72]

dont take this the wrong way but you are checking the fluid level while its idleing in park right?

[rough69]

Yes I am checking the fluid level when trans is hot and in Park and the level is fine, fluid looks ok.

The converter really does have a plug on it! I will take a pic of it tomorrow it is weird...

I have 295/50/15 so a 26.6" tire with 4.11s and 65MPH is over 3500 RPM wow.

Maybe I should slap in an overdrive box?

[mrein3]

Originally Posted by rough69

Yes I am checking the fluid level when trans is hot and in Park and the level is fine, fluid looks ok.

The converter really does have a plug on it! I will take a pic of it tomorrow it is weird...

I have 295/50/15 so a 26.6" tire with 4.11s and 65MPH is over 3500 RPM wow.

Maybe I should slap in an overdrive box?

I have seen torque converters with drain plugs. While working my way through college I worked at the local repair shop. When you changed fluid on one of them you pull that plug and then go to lunch. It takes a long time to drain them down.

I saw them mostly on Ford trucks.

[rough69]

Well here is a shot of my "Ford Truck" converter then

The more I think about it, a 200-4R swap is sounding pretty good, provided I can score one and afford the more expensive rebuild and other parts.

For how cheap it is I'll probably get this TH350 rebuilt and keep running with it, I can always swap rear ends later...

[WorkinLonghorn]

The PO probably drilled and tapped it. We used to have kits for doing this but if my memory serves me (for once) the kits had a very small allen plug that fit in the hole. I guess that balance was an issue. Spinning at 5000 RPM,that bolt the guy put in there is possibly going to cause vibration,etc. I don't know.