Noise

[ropinfool]

Ok, my wife calls me on my cell today (she's been driving this truck) tells me the truck won't stay running. I'm at least an hour away. She tells me she just got it parked, in a Target shopping center of course, and I need to pick her up. I ask for more info. She just says it won't stay running but will start up every time. I ask how much fuel she has, 3/8 tank, tell her to switch tanks but she says she'll wait for me. I finally get there, have to drag her out of the fitting room. Go out to the truck and switch tanks, truck fires right up, have kind of a wierd vibration. Put it into gear and it sounded like a bunch of nuts and bolts in a blender. I checked the tranny fluid and it was full and bright pink. I'm thinking torque converter??? She also said she started loosing power on the freeway, barely made it off the main road. Any ideas??? Sorry for the long post. If it's a tranny, how much to change over to the 700r4? I'll be doing the labor. TIA. John

[gmctd]

Check the converter to flywheel bolts - may be one out.

Finding the t-case adaptor and coupling for the 700R may be a problem.
Woulda helped if the trans had been T350, which is identical output bolt pattern and shaft to 700R.
If you find a set, the T400\700R length is similar, so driveshafts should be ok.
The shift pattern template in the steering column, and the indicator, will need changing.
And, you'll need the throttle-cable bracket and Torque Converter Clutch brake-switch.
The 700R should have the K case, with a Diesel torque converter, as in Dr. Lee's article.

Other than that, it's drop-and-swap. ;)

[ropinfool]

Thanks gmctd, I'll check the bolts tonight. I was thinking of the same co. Doc used. The price didn't seem too bad to me, it's just finding the money to pay for it as my wife just got laid off. She's been driving this truck as her daily errand runner. Could the internals of the torque converter have let go? Any other ideas???? Thanks. John

[britannic]

YMMV, but when my T/C let go it sounded like a cement mixer running 650rpm at idle :D !. I had the transmission rebuilt as well, since the shrapnel from the T/C will hit the pump and clutches before they finally get filtered after returning to the pan.

[ropinfool]

Well I haven't checked the bolts yet, but have been calling around to get prices for a replacement tranny. That is almost unheard of around here. They all want to rebuild my tranny, pricing is ranging around $800. For a couple of hundred more I'm seriously thinking of the O.D. unit. One of the shops I've talked to says it might be my transfer case that went?? I didn't think that was a possibility since I was in 2 hi with the hubs locked out. What do you guys think?? Could it be the transfer case?? By the way the truck will not move under it's own power. TIA. John

[gmctd]

While it sounds worse and worse, John, I would suggest an up close and personal inspection, if you're up to it.

Could be torque converter, front pump, input shaft, etc - any of these should show up as stuff in the oil, and in the pan.
But - you mentioned clear pink fluid, which would seem to indicate not a transmission problem.

Fluid in the pan is oil that has gone thru the pump and transmission, so with any damage it should have been full of metal flakes, the truck having been very recently driven.

Remove the transmission pan and check for 'stuff' or -

Remove the flywheel cover.
Jack the rear wheels up, set the jack stands, get under the truck, have the 'significant other' crank it up in Park, and observe.

Foot on brake, to Reverse, release brake slowly.
Foot on brake, to Neutral, release.
Foot on brake, to Drive, release.
Foot on brake, to Park again.

Check the noises in each position - one position or the other should indicate worsening or lessening in noise level.

Note if noise is in torque converter, transmission, or transfer case.

Should indicate which direction you'll need to take.

[ropinfool]

Thanks GMC, I think I have the wife talked into an overdrive. So I don't want to do anything to spoil that. The prices I'm getting for a rebuild aren't much less than buying one like Doc Lee's. My next question is, will I have to do driveline work or is the 700r4 tranny approx. the same length at the T-400. I know I will need to let whoever I buy it from know it is 4x4 so the output shaft will match. I'm also concerned with hooking up the lock-up function as well as the shifting mechanism. Thanks again and keep the info coming!!! John

[britannic]

There's about 1/2" difference, so no driveline work needed - I've done two of those conversions now. Just make sure you get the right t-case adapter (TH700R4 4 to 6 bolt) and check if you need the long or short foot version by looking at your existing adapter and as you say the t-case input shaft will either need changing or better yet, get the 700R4 built with the correct output.

I used Transaction Transmission and Gear in Sun Valley, Los Angeles, and had them build me a "Bad Boy" 700R4 - if you contact them, ask for Bernie or Brad and mention you heard about it on the Diesel Page.

[mhagie]

Bowtie Overdrive has a wiring kit available at a reasonable cost to wire the 700R4 to any vehicle,a diagram is also on their web site 700R4.com, I believe it is around $25.
Also 700R4 t/case parts should be readily available at most salvage yards cause around 80% of 4x4 pickups from 82 up were of the 700R4 variety.

[gmctd]

Hey, Merle...long time no post.
You outta hibernation? ;)

[ropinfool]

Thanks for the replies. Bowtie wanted to sell me their level 3 tranny as soon as I mentioned diesel. On their website this level is good for up to 650 hp. I tried to explain that the 6.2 doesn't make that kind of power but I honestly don't know where we are at stock. I'm guessing 150 hp??? I know I'm below 350 hp which is what their level 1 tranny is rated at. Now I want a tranny that will last but I don't want to spend my money on huge overkill. I wasn't super impressed with the tech I talked to. Kept asking me if I was fuel injected, had to remind him several times Diesel. Told me I would have to do driveline work and recommend moving the engine. "That's what I do" quote. I'm not ready right now, but can't leave it parked on the street very long. Thanks. John

[DmaxMaverick]

The horsepower arguement....
A reasonable 6.2/6.5 will never reach the HP limit of even a stock tranny. The tranny's are rated at X horsepower max, which is generally considered with a gasser application. The Diesel engine is very different. The horsepower may get up there, but at half the RPM's. That means input torque at a given RPM is exponentially higher than a gasser. The tranny is also rated at max input torque for this reason. That is the rating number you need to consider. The torque rating needs to be considered as an "input" number, as opposed to a "rear wheel" number (the tranny is the parasitic factor, not the result). That means the horsepower/torque at the flywheel, not the rear wheels. If you have a parasitic loss of 15% through the powertrain, about 12% of that is lost in the tranny. This is why a tranny that is rated for X horsepower will work fine in a high output gas engine, and die very soon if behind a Diesel engine. Tranny's are much more tollerant of high RPM torque than low RPM torque of equal value.

It all comes down to how much energy is exerted on a given mechanical part (such as a gear or friction surface). For example, if your peak torque is 400 lb./ft. in both a gasser and Diesel engine, and the gasser peaks at 4000 RPM's compared to the Diesel peaking at 2000 RPM's, the Diesel engine will exert more than twice the energy on the part. The reason it is more than twice the number is the RPM the energy is released onto the mechanical parts. The 400 lb./ft. of stress in the gasser example is spending much less time on the given part than the Diesel example.

That being said, a transmission builder's statement that a tranny is rated for 350 HP (for example) is not enough information in most cases, especially when it comes to a Diesel application. This doesn't even cover the effects on a tranny at the output end, where torque multiplication through gear reduction really puts the stress on mechanical parts. If it were simple, we wouldn't need engineers to figure all this stuff out....

Cheers

[garysleeman]

I did a similar replacement in a 82 1 ton(NP205). Purchased from Advance Adapter special output shaft and transmission to transfer case adapter. I think the cost was $250. No driveline or any other changes required (used non electric converter lock-up).

[ropinfool]

UPDATE:
Last night I went out and checked my torque converter bolts, all tight. Jacked the truck up (rear axle supported on jack stands), had the wife start it up and put in gear. Noise is definately coming from torque converter/front of tranny. No power being transfered to wheels. Bad vibration also at idle. I'm guessing torque converter. I haven't pulled the pan so I don't know what kind of trash is there. My question is if the tc went bad, is the tranny ok? I'm not sure of the lube pathway so how does the oil circulate through the tc into the tranny? I'm trying to save money, wife's been laid off a month now, savings is getting thin. I would love to put in an overdrive unit but can't part with that much dough. Any suggestions are appreciated. Thanks. John

[britannic]

When the T/C fails, any debris will go through the pump unfiltered, then it'll hit the clutches before it finally dumps in the pan. IMHO, get the tranny rebuilt - I had to, when my 700R4 T/C failed and they found shrapnel in the clutch packs.

[ropinfool]

Thanks Brit, not what I wanted to hear but what I suspected. A wrecking yard unit with tc is about $500, I was quoted anywhere from $500-800 for a rebuild. How do I flush the tranny coolers and lines?? I have a plate type cooler with orifices to determine how much cooling is needed. If any metal gets in there it may be screwed! It's only 2 years old. Almost everything on this truck has been done in the last 3 years, the tranny was done in Sep 2002, has less than 20k miles on it. That was in Wa. and shop wouldn't honor anything past 1 yr warranty anyway. Thanks. John

[wthif]

I have a tranny you might be interested in. email wthif at netzero dot com

[ropinfool]

UPDATE:
Well I haven't had any time to work on this myself so I found a local shop with a good rep. and had them start on it. The fluid looked good, some shavings in the pan. Picked up the TC and shook it, sounded like a bunch of rocks in there. So I'm guessing we found our problem. I am going to have him go through the tranny, kinda sad it only has 20k miles on it since the last rebuild, but it doesn't look like it's going to be that expensive (I hope!!). Anyway I'll keep y'all informed. John

[ropinfool]

UPDATE: Well I got my truck back the other day, have to say I'm very disappointed. The tranny is fine, just still having all the same problems, so the old torque converter wasn't the culprit. So I guess it's back to square one. John