Dropped my truck off at the Transmission Shop.

[veinbar]

I dropped my '79 Bonanz off at the Tranmission shop this morning for a routine Trans-Tune and Fluid/filter change. My truck has a TH400 that was rebuilt 2 years ago and is just outside of it's warranty. It probably 20K or less miles on it, but I thought I'd take it in for routine/preventitive maintenance. He called me back with bad news.

1. My trans fluid is black meaning my clutches are burning up.
2. I need a dust cover.
3. My dipstick tube is not bolted onto the bell housing and is bent.
4. Rear seal is leaking.
5. It's missing the wiring for a kickdown.

All in all, I don't think I got what I paid for 2 years ago. He advised me not to change the fluid because it could potentially ruin my transmission at this point. He said keep driving it until I decide my next move.

He quoted $950 for a rebuild and correction of said problems. Does that sound right to you guys? I live in Austin TX btw...

[Jonboy]

If that is the case, I would look at swapping to a 700R4 when the current 400 goes.

[J Knight]

If he did the O/H 20k ago, I take it to another shop. The price sounds about right for all those repairs.

[Doug_J]

sound kinda weird 20k miles and clutches are burned up. Inless its because the fluid has been low for a while because of the seal leaking and tube not being hooked up, but the kick down and dust cover are not a big deal.

[Hoods69BadBowTie]

Yea the only thing I could see as causing that would be the fluid leaking. That sounds kinda steep but that might just be me. My last TH350 rebuild was like 600$. Is this the same shop that did it last time or a different one?

[veinbar]

Originally Posted by J Knight

If he did the O/H 20k ago, I take it to another shop. The price sounds about right for all those repairs.

This is a different shop than the one that did the rebuild. The rebuild was done by a shop in Bastrop, TX. I'm going to Eagle Transmissions in Austin, TX as my primary Transmission Shop now. They've earned a strong reputation around Austin with other repair shops, and they seem honest / knowledgeable.

[QUOTE=J If that is the case, I would look at swapping to a 700R4 when the current 400 goes.[/QUOTE]

I love this idea, but there are a few issues to consider:

1. My GM 12 bolt rear needs to be rebuilt or replaced. Rebuilds are expensive, and junkyard replacements are a crapshoot when looking for a decent ratio to pair with OD Transmissions.
2. My TH400 has a different yoke and a 2-piece drive shaft. If I switched to a TH350 or 700r4, could I convert to a 1-piece drive shaft?
3. Would the shifter linkage need to be modified?

Also, is it true that a TH400 robs more HP and effects MPG moreso than a TH350? I know a TH400 is more transmission than I need for my application, but it was in my truck when I bought it.

Any feedback or advice is always appreciated.

[veinbar]

Originally Posted by Doug_J

sound kinda weird 20k miles and clutches are burned up. Inless its because the fluid has been low for a while because of the seal leaking and tube not being hooked up, but the kick down and dust cover are not a big deal.

Seems odd to me too. I check the fluid levels on my truck at least twice a month, or any time I'm driving 50 miles one way. The trans fluid never looked discolored to me on the dipstick. I did notice that the trans tube was loose, but ignored it like an idiot. I'm sure fluid could escape from there.

[Doug_J]

Shouldnt be a problem to putting a one pice on their for the th350 or 700r4, the th400 does take a little more hp to turn. I'd say 4.10 wouldnt be a bad gear to go with the 700r4 but also depends on tire height an so on but salvage yrds not a bad place to go look just pop the cover off an look at the gears.

[meter swinger]

Just had two trannys done and that sounds about right $$$$ wise for where im at. My trans guy told me that 400's are known for ditry fluid. What sounds odd to me is his recomendation to not change the fluid. This is generally a given for a trans with alot of sludge in the pan, that you don't want to do a complete "flush" of the trans cause it will send trash all through the unit. But just changing filter and fluid in the pan i would think to be safe. Does it hesitate to shift at all? Like taking off from a dead stop particularly when not fully warmed up? I would consider a second opinion berfore doing anything major unless your getting symptoms while driving. At the worst your out another 70$ for a shop to pull your pan. And ask if you can be there and look at the pan and fluid when they pull it.
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[Doug_J]

Originally Posted by veinbar

Seems odd to me too. I check the fluid levels on my truck at least twice a month, or any time I'm driving 50 miles one way. The trans fluid never looked discolored to me on the dipstick. I did notice that the trans tube was loose, but ignored it like an idiot. I'm sure fluid could escape from there.

I'd say if it aint dark and dont smell burnt I'd maybe take it elsewhere for another opinion. Im sure that shop got his money and charged you his one hr min. and didnt have to do anything just saying you never know maybe a real honest shop.

[meter swinger]

^^^ like reagan said "trust but verify"
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[Clyde65]

I have heard the "dirty fluid" thing for 700's with lots of miles on them, but never a 350/400. and ur right a 400 will rob some performance from the engine, but it is almost bullit proof. A second opinion would be the first thing I would do, not that you dont trust the guy, just for your piece of mind.

Also I would call the other shop that originally rebuilt it and tell them what is going on, maybe take it to them. they may or may not care, but you wont know that until you ask.

I had a similar situation with a 68 Cutlass, I did call the trans rebuilder and although it was out of the warranty, they rebuilt it for parts only, I think it was maybe $200 total for parts. saved their reputation and my wallet.

[veinbar]

Originally Posted by Clyde65

Also I would call the other shop that originally rebuilt it and tell them what is going on, maybe take it to them. they may or may not care, but you wont know that until you ask.

I didn't even think to do this. Thank you. I will call them before I do anything else. Rebuilding the th400 would be the cheapest route, but now I'm stuck thinking about the 700r4 conversion...

[Jonboy]

Just to help you out with the 700R4, it has a lower 1st and 2nd gear to go along with the overdrive.

[78 Chevyrado]

i'd be wary of people telling you flushing the fluid will ruin it the rest of the way. I've never come upon a machine yet that flushing the fluid properly would hurt it. also if old burnt fluid was helpful they'd put it in at the factory.

burnt fluid will damage your trans because its not working properly and its properties have changed. you should get it out of there as soon as ya can.

[chevy-fun]

Changing the fluid is a hit or miss imo if its bad. Might help then again the fresh slick oil oil could accelerate the destruction. Happened once to me an few wks later went out completely.
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[lunchbox99]

if all your friction material is in the fluid, and you get rid of the fluid, there is now no friction material to make clutch grab each other...I have seen a few that would not even back off the rack, but not at 20K!!! call the last shop that overhauled it. 20K is ridiculous!

[veinbar]

Originally Posted by lunchbox99

if all your friction material is in the fluid, and you get rid of the fluid, there is now no friction material to make clutch grab each other...I have seen a few that would not even back off the rack, but not at 20K!!! call the last shop that overhauled it. 20K is ridiculous!

You're telling me... Especiallly on a TH400.

So I picked my truck up and I was told that there were a lot of upgrades that had been done to this transmission. Shift Kit, and other various heavy duty gadgets. He told me to drive it until I figure out what I want to do and it should be fine. He told me that this TH400 would/could be a valuable core for someone who needs it. He said TH350 and 700r4 transmissions are a dime a dozen and I should be able to pick out a good core for $100 or so, and that I could sell my TH400 core for $250 easily. That makes me feel a little bit better I suppose. Eh... Where do I go from here?

[motornut]

if you drive average 10,000 a year thats two years
not right,can't see that being as acceptable
i'd go back to the shop that built it

I've heard of the "don't take the old fluid out" thing but never listened
new fluid and filters are a good thing
but i have added "duralube" for the tranny to stop some slipping
and found it helps them last
and without doing the fluid and filter

78 Chevyrado said it best lol "if old burnt fluid was helpful they'd put it in at the factory"