700R4 Noise and Fluid Temp Issue

I have a 1983 Chevy Van Motorhome, which I guess hardly qualifies as a hot rod. Still hoping to find some knowledgeable people here to give some advice.
The vehicle has a 6.2 non-turbo diesel engine. The original transmission was a TH400, which I replaced with a rebuilt, beefed-up (700hp) 700R4 from what I thought was a reputable transmission shop. It has a lock up torque converter.
I talked to the shop about my problems but didn't like very much what they told me. So I'm trying to get a few more opinions here.

Here are the issues I have.

1. The transmission shifts fine and performs nicely and quiet up to 3rd gear. In overdrive it emits a slight howling noise, most pronounced around 60 - 65 mph. If I engage the lock up the howling gets much worse to the point where you want to disengage it right away. If I keep it locked and go faster it quiets down somewhat but the noise is still there and it simply shouldn't be with a new tranny.
There is absolutely no noise in 3rd gear, with and without lockup.
The front part of the drive shaft had to be shortened. I had this work done by a professional drive shaft shop. My first suspicion was that the drive shaft was out of balance but the people who shortened it assured me they balanced it.
The drive shaft has all new u-joints and a new center bearing.
Has anyone any ideas on where the noise comes from?

Note: here is what the transmission shop told me. My lockup solenoid gets 12V from a separate brake pedal switch to allow disengaging of the lockup when braking. The ground wire runs to a dash board switch and then to ground. They think there is a bad or insufficient ground for the lockup solenoid. They think I should ground it right on the tranny and put my dash switch in the hot line.
I'm having a hard time believing that's the problem but I might be wrong.

2. I also have a temperature problem. When cruising on the highway at around 55 mph the fluid goes to about 230F, around 70 mph it is up to about 250F. This is without the converter locked due to the howling problem mentioned above.
The transmission shop people said it was not a problem to drive the 700R4 without lockup, but I have read other statements just to the contrary. I'm not using the radiator integrated oil cooler but a 20,000 lbs GVW rated stacked plate cooler in front of the radiator.
Now my temperature problem is probably related to not using the lockup. I'm still surprised that the transmission generates that much heat.

I'm not sure if I mentioned everything that is important. If something's missing let me know. I would really appreciate your input.

Those temps are gonna cook the trans to an early retirement. I had a lengthy chat with the owner of Bowtie Overdrives many years ago. He stated that for every 10 degrees over 220, the trans life is shortened by half. Under normal driving conditions/temps, the trans should live around 250K miles. You really need to use the radiator trans cooler first then run it through the stacked plate cooler second. I dont believe the stacked plate cooler is sufficient as the primary cooler. This will drop your temps a ton. As far as the growling in 4th gear, the only difference between 3rd and 4th, is the 2/4 band is applied. I wonder if it's slipping? Have you put a pressure gauge on the trans to see what your pressures are? As you may or may not know, the 700R4 has the tricky TV cable, that controls line pressure. Not enough and she goes up in smoke. Something this trans has a very good reputation for.

Keith

Thanks Keith for the reply.
I initially ran it with the radiator trans cooler only, and the temperatures were similar. I figured that a large external cooler has better cooling capacity than the radiator cooler. Apparently it doesn't. My next step as far as trying to control temperature is using both coolers, as you suggested.
I am aware of the TV cable. I had to fabricate a bracket for the TV cable as they aren't available anymore, at least not for the diesel engine. The injection pump does have a hookup for the cable. There are diagrams available that show the correct geometry of the TV cable hookup, and I followed that closely. I used the wide open throttle method to adjust the cable, which basically means max throttle equals max travel on the TV cable. I have not checked the line pressure, which I should probably do. Where exactly is that pressure reading being taken? Also, can you give me the procedure on how to do it?
You say the only difference between 3rd and 4th gear is the 2/4 band being applied. Isn't there another major difference? In 3rd gear the ratio is 1:1, meaning none of the planetary gears are actually being used, while in 4th gear, with a ratio of roughly 0.7:1 the drive shaft runs faster then the engine. Could the howling be coming from the planetary gear set? Then why would it be so much worse once the TC lockup is engaged?
Steve

I'm not a tranny guy, but you mentioned that the tranny shop questioned your ground bring good for your lockup. Do you have your engine, frame and body bonded together with good, clean ground straps on bare metal connections? You can very easily check your ground circuit by running a temporary jumper wire from the isolated side of your lockuup switch direct to the battery, then try your lockup switch. If the noise goes away the shop was right and you have an easy fix.

Try to go with the TCI constant pressure valve body the eliminates the need for the critical adjustment of the TV cable.The TV cable is then used for a kickdown only.There are two reasons I am suggesting this-one being it is a custom set-up and the second one being these trans do rely on that TV cable adjustment to be correct and I think the heat up issues are directly related to the trans slipping.I think it is your interest to contact TCI tech to talk about the issues your are having.

Home - TCI® Auto

The pressure tap is on the left side of the trans above the shifter. You want to make sure you see an immediate rise in pressure when the throttle is slightly advanced. That diesel has mongo torque, you don't want to fry the clutches due to low line pressure. It's cheap insurance to check your pressures. Per my ATSG reference books I have, it says for D4-3rd gear: fwd sprag holding, fwd clutch applied and 3/4 clutch applied. For D4: fwd sprag clutch NOT holding, fwd clutch applied, 3/4 clutch applied and the 2/4 band applied.
If the problem happens only when the converter is locked I would manually lock it in D3 via a manual switch you can wire in. Good old fashion troubleshooting! Running both coolers will get the temps down to reasonable levels. Run it into the radiator 1st then the aux. cooler second.

Keith

How much does the whole rig weigh??? Possibly more weight then you have transmission????

Wow Ive never heard of a 700r4 behind a diesel with the torque and all, I was sweating it out just wondering if it would hold up behind my sbc 383, may be common don't know. I did put the TCI constant pressure valve body in mine just for the reason that with 2x4s I was afraid I wouldn,t get the TV cable set correct. Bowtie overdrives helped me out with the correct carb. linkage adjustment for the cable. I also put a Gear vendors overdrive but have yet to really test the combo except around the block, long blocks.Hope I didn't get to far off track here, but trans temps were stable,pressure scared me! also just going thru radiator for cooling, but not trying to move 4000 plus lbs

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Originally Posted by blwn31

Those temps are gonna cook the trans to an early retirement. I had a lengthy chat with the owner of Bowtie Overdrives many years ago. He stated that for every 10 degrees over 220, the trans life is shortened by half. Under normal driving conditions/temps, the trans should live around 250K miles. You really need to use the radiator trans cooler first then run it through the stacked plate cooler second. I dont believe the stacked plate cooler is sufficient as the primary cooler. This will drop your temps a ton. As far as the growling in 4th gear, the only difference between 3rd and 4th, is the 2/4 band is applied. I wonder if it's slipping? Have you put a pressure gauge on the trans to see what your pressures are? As you may or may not know, the 700R4 has the tricky TV cable, that controls line pressure. Not enough and she goes up in smoke. Something this trans has a very good reputation for.

Keith

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I'm getting a pressure test kit to take line pressure readings.
I'll post the readings once I have them - it'll be a few days.
Thanks for all the replies!
Steve

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Originally Posted by Dq383500

Wow Ive never heard of a 700r4 behind a diesel with the torque and all, I was sweating it out just wondering if it would hold up behind my sbc 383, may be common don't know. I did put the TCI constant pressure valve body in mine just for the reason that with 2x4s I was afraid I wouldn,t get the TV cable set correct. Bowtie overdrives helped me out with the correct carb. linkage adjustment for the cable. I also put a Gear vendors overdrive but have yet to really test the combo except around the block, long blocks.Hope I didn't get to far off track here, but trans temps were stable,pressure scared me! also just going thru radiator for cooling, but not trying to move 4000 plus lbs

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The transmission place knew the vehicle specs.
I have seen statements on other forums that said something like "a stock 700R4 isn't gonna make it a week in a 1-ton chevy van or truck."
Pretty much all the well known transmission places build several levels of beefed-up transmissions, calling them different names.
Mine is level-2 of three available levels. They say it's made for 700 hp and the corresponding torque. The 6.2 diesel only has around 120 hp.
So I'm fairly confident that my unit is built strong enough to handle the weight of the motorhome.

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Originally Posted by Dave Severson

How much does the whole rig weigh??? Possibly more weight then you have transmission????

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Good question. I think the maximum GVW is 10,500 lbs. I'll have to drive it over a scale to find out the actual weight.
As I said it's not just a stock 700R4 but a beefed-up version.

Honestly, the transmission shop that built it should stand behind it. I hate when you pay good money, and now it's your problem. It's sad what has become of many businesses.

The 700R4 was installed behind diesels. So, they can handle it. I believe they have a different convertor, has to do with the over-run circuit of the trans. I briefly remember reading about in one of my ref. manuals.

Keith

I would think a diesel 700R4 would have a much lower stall speed to hold down the "R"'s and take advantage of the torque.Toni my trans guy told me awhile ago is the biggest problem a 700R4 has is it doesn't circulate tranny fluid very well while locked up.That is one of the main reasons while towing in other than flat land even with a cooler you tow in 3th.I got to wonder how the wt of the RV effects that.Now I want to say that in my build plans I am going to use a TCI parts rebuilt 700R4 with a high torque 383 going in about a 4,000 lb Astro van towing a 3500 lb trailer.But in all fairness,we use to have a Suburban with Art Carr parts in it towing anything from a 6 x 8 trailer to a 22 ft trailer.We would check the fluid in Buffalo and go to Cleveland,Ohio.When we got back,you could see partials in the fluid and we didn't beat on the truck at all towing mostly in 3th.After awhile of owning Suburbans with 700R4's we actually on purpose bought a earlier model so we had the use of a 400 trans.As I think about this more,I think a 400 with the Gear Vendors trans is a better set up than the 700R4 with one.You could also get more feedback on this RV site.Look under the Vintage section for RV's.

iRV2 - The Friendly RV Forum Community

I just figured my fuel economy for a recent weekend trip! Actually first trip with the 700R4.
I only got 11 mpg with the 700R4. With the old TH400 3-speed I was getting 18 mpg, and the overdrive transmission was supposed to improve it.
There is definitely something wrong. What are you guys getting with the 6.2 and 700R4 tranni?

I don't have enough miles on my setup to give mpg, although I don't expect it to be good. In just the little driving I have done I can tell with the 700r4 there's no way with the gear vendors I can pull double overdrive as the engine is just out of the sweet spot,
What I'm getting at is I wonder if when your in overdrive could you be off the sweet spot? I know it's a diesel but isn't their a cruising rpm that is preferable.

Three things(again)one Call TCI tech line as I said,two,I don't think jury rigging you going to get the correct TV cable adjustment,three if that is wrong,you going to burn up the 700R4.NOT a guess here,just a matter of time.

Now I can only suggest the best path for you to take,BUT if you decide not to follow that,it is all I can do.

I got to be honest with you.I am aggravated abit because I gave you a ref to the best RV site on the web and I can tell you never even bothered to look by what you are posting.That equals to any of the advise anyone gave you and you not taking it.It is kind of frustrating.BTW-a trans shop telling you a trans can handle 700 hp needs to put on their big boy pants.Because 700hp means something different to a 1800lb vehicle than it means to a 8000 lbs one in terms of a trans.Sooooooooooo what they said logically means not much.

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Originally Posted by Dq383500

I don't have enough miles on my setup to give mpg, although I don't expect it to be good. In just the little driving I have done I can tell with the 700r4 there's no way with the gear vendors I can pull double overdrive as the engine is just out of the sweet spot,
What I'm getting at is I wonder if when your in overdrive could you be off the sweet spot? I know it's a diesel but isn't their a cruising rpm that is preferable.

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I was trying to get closer to that sweet spot with the overdrive transmission. With the old TH400 the engine was revving high at cruising speed of about 55mph. It really didn't feel comfortable going any faster. And with this setup I was getting 18mpg towing my Saturn SL2 on a dolly.
Now the whole idea was reducing the engine rpm with the overdrive transmission, so that I could go a little faster, with less noise and slightly improved fuel consumption.
I was aiming at like 20mpg. I agree with you as far as the "sweet spot" goes. I'll have to figure out what the best cruising speed is for the best fuel economy.
However, first I guess I have to figure out why this many gallons of fuel were just turned into transmission heat instead of miles on the road.

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Originally Posted by 1gary

I got to be honest with you.I am aggravated abit because I gave you a ref to the best RV site on the web and I can tell you never even bothered to look by what you are posting.That equals to any of the advise anyone gave you and you not taking it.It is kind of frustrating.BTW-a trans shop telling you a trans can handle 700 hp needs to put on their big boy pants.Because 700hp means something different to a 1800lb vehicle than it means to a 8000 lbs one in terms of a trans.Sooooooooooo what they said logically means not much.

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I've got to take exception to your getting frustrated. The site you mention may be good or even the best.. but it is YOUR opinion! Someone asks a question and you graciously offered guidance and YOUR opinion. Remember the old saying, you can lead the horse to water but... your not gonna make him drink!

Don't get aggravated and then complain because someone didn't immediately run to your selected site or follow your advice in what you determined to be a reasonable amount of time. Not all of us can spend so much time surfing the web or doing a bunch of research to a problem. That's why we get together in these forums and discuss our "issues" good & bad.

I humbly offer the above that you can shake off this issue and accept that you cannot live the posters life and cannot make his decisions, you can offer your OPINION and your ADVICE and leave it at that. We all hope that things work out for the best for the OP and I think we all would agree that your passion for helping others is evident but don't let that get you into a bad mood! And I hope you can accept what I've written in the spirit it was intended. It's just a vehicle after all! :LOL:

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Originally Posted by 34_40

I've got to take exception to your getting frustrated. The site you mention may be good or even the best.. but it is YOUR opinion! Someone asks a question and you graciously offered guidance and YOUR opinion. Remember the old saying, you can lead the horse to water but... your not gonna make him drink!

Don't get aggravated and then complain because someone didn't immediately run to your selected site or follow your advice in what you determined to be a reasonable amount of time. Not all of us can spend so much time surfing the web or doing a bunch of research to a problem. That's why we get together in these forums and discuss our "issues" good & bad.

I humbly offer the above that you can shake off this issue and accept that you cannot live the posters life and cannot make his decisions, you can offer your OPINION and your ADVICE and leave it at that. We all hope that things work out for the best for the OP and I think we all would agree that your passion for helping others is evident but don't let that get you into a bad mood! And I hope you can accept what I've written in the spirit it was intended. It's just a vehicle after all! :LOL:

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In the sprite of all of the regulars being a family affair and being offended this O/P ignored everyone,I am simply defending everyone and all the good intentions everyone put for in advise.Also-it is rare that I get this wound up.After all this isn't my first rodeo on forums.But thanks for the thoughts.

The ref links and not the least iRV2 is the same thing as me telling someone about this forum and for some very good reasons..............

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Originally Posted by 1gary

I got to be honest with you.I am aggravated abit because I gave you a ref to the best RV site on the web and I can tell you never even bothered to look by what you are posting.That equals to any of the advise anyone gave you and you not taking it.It is kind of frustrating.BTW-a trans shop telling you a trans can handle 700 hp needs to put on their big boy pants.Because 700hp means something different to a 1800lb vehicle than it means to a 8000 lbs one in terms of a trans.Sooooooooooo what they said logically means not much.

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I really don't know what you are getting so upset about. I admit I haven't been on that RV site, simply for a lack of time. This is a motorhome. It's not my primary vehicle. I'm in not too much of a hurry to get this issue fixed. The vehicle is not being driven in this condition so I won't burn up the transmission any more than it already is.
I am in fact considering all the feedback I'm getting here.
I know very well that adjusting the TV cable correctly is crucial for this transmission, as I have said somewhere in one of my replies above.
I'm going to work on this as soon as I get the pressure test kit.
Using the constant pressure valve kit from TCI is certainly a good option, but it adds another $250 to a project that has already gone way over budget (not talking about the transmission here).
BTW - I'm pretty sure the TCI tech is gonna ask me what my line pressure readings are. So I should know those before I call, don't you think?
As far as the transmission shop people are concerned - they build the transmission specifically for my application.
They knew the vehicle specs, the engine, and especially the fact that it is heavy.
They said the trans can handle that weight. If in fact it cannot I will go back there and shove it up their...
But I'm not at that point yet. For now I'm just trying to figure out what the noise in OD lock up is, and why it's turning so much of my gas mileage into heat.

So please don't be upset that I haven't run out yet to get the part from TCI.
My next step is taking pressure readings and making sure it's not an issue with the TV cable adjustment.
Thank you for your and everybody else's input.

Don't sweat it.
You don't need the part from TCI.

Setting up the cable correctly is all thats req'd.

I had an issue with an aftermarket TV cable that was binding inside the sheath and it felt as though I was at full pull when in fact is was actually hung up.
I discovered this by dropping the pan and having someone work the throttle and seeing the valve not fully depressed.

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Originally Posted by steve48348

I was trying to get closer to that sweet spot with the overdrive transmission. With the old TH400 the engine was revving high at cruising speed of about 55mph. It really didn't feel comfortable going any faster. And with this setup I was getting 18mpg towing my Saturn SL2 on a dolly.
Now the whole idea was reducing the engine rpm with the overdrive transmission, so that I could go a little faster, with less noise and slightly improved fuel consumption.
I was aiming at like 20mpg. I agree with you as far as the "sweet spot" goes. I'll have to figure out what the best cruising speed is for the best fuel economy.
However, first I guess I have to figure out why this many gallons of fuel were just turned into transmission heat instead of miles on the road.

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ya know 1gary,,, makes some very valid points, yes it will burn up without correct TV cable set up, I would think that you would have allready done so with the miles you have on it with MPG and all. I had to use Lokar cables for throttle and TV cable so as you know It became important to get the setup correct. Bowtie overdrives has a very good website that will help with the pressures and such in each gear. I did purchase from them a piece of linkage that fits on the carb linkage because im running edelbrock carbs and not the stock qjet, the geometry must be correct for the pull of the tv cable. as far as the high tranny fluid temp I don't know on that one, I would think if slipping It would allready be done I went back reread the original post and as far as the noise I can only guess that the planitaries are noisy best guess here and only a guess wish I could help more enjoy the camping! By the way my 2004 Nissan Titan only gets 15MPG on a good day pulling nothing!

18mpg on any RV deserves a bumper kiss.So go out right now and take care of that next.:whacked::rolleyes::LOL::LOL:

I got some work done this weekend, so here is what I found.

I took pressure readings. From what I found the line pressure in OD should be 90-110psi minimum and 190-230psi max. Mine was 70psi at idle, didn't increase much until I was at around 50% throttle, around 100psi when cruising at 55mph in OD, and maxed out at about 130psi at full throttle.
Readjusted the TV cable so that pressure increases as soon as I hit the accelerator.
Readings are now 70psi idle, increases quickly to 100, 120psi. It's around 150psi when cruising at 55mph, and maxes out at about 180psi.
Still a little below the should-be ranges but better than before. Any thoughts about the pressure readings?

The howling noise at 60mph in OD with TC locked hasn't changed at all.
Rewired the solenoid. Simply gets 12V from a toggle switch and is grounded right at the transmission case. No difference. I figured it wouldn't make a difference since the solenoid only draws about 1/2 amp so cable length doesn't have much of an impact.

Drove a few miles today to take the pressure readings. After readjusting the TV cable I did about 30 miles of highway driving in OD with the TC locked (despite the noise) and found that the oil was staying around 160F.
It seems like most of the heat issues I had on my recent trip came in fact from the TC when it ran unlocked.

Now here is something else I found.
Took the drive shaft and the tail housing off to find out the speedometer gears installed as my speedometer is about 18% too fast. There seems to be a lot of play in the rear main bearing. I would guess the play in the bearing is about 1/32 of an inch, which I think is a lot. The rear end of the output shaft moves almost 1/4" up/down or left/right. I got a feeling that's where my noise and vibration is coming from.

Check out this video and photos:
http://s1103.photobucket.com/albums/...110911a006.mp4
http://s1103.photobucket.com/albums/...110911a002.jpg
http://s1103.photobucket.com/albums/...110911a001.jpg

I don't think a freshly rebuilt transmission should have this kind of play.
Let me know what you guys think.

Thanks a lot.
Steve

We and I am including myself have much to offer in advise,but the advise I insist you could get for free is the TCI tech line.No cost if I didn't make my point clear.Do yourself a big favor,tomorrow call them up letting us know what they said and then tell you trans shop what you think is the problem armed with that information.Remember-it is cost free.

That line pressure isn't going to get it done.

Again

www.TCIAUTO.com

The play in the output shaft is normal.

The yoke takes up the slack when it slides in. It rides in the bushing at the rear of the extension housing.

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Originally Posted by 1gary

We and I am including myself have much to offer in advise,but the advise I insist you could get for free is the TCI tech line.No cost if I didn't make my point clear.Do yourself a big favor,tomorrow call them up letting us know what they said and then tell you trans shop what you think is the problem armed with that information.Remember-it is cost free.

That line pressure isn't going to get it done.

Again

Home - TCI® Auto

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Talked to a TCI tech as you recommended.
They're saying my line pressure is too low at 70psi. On a rebuilt transmission the pressure should be 110psi. Depending on what causes the pressure to be that low the constant pressure valve body they sell may or may not fix the pressure issue.
The guy said the tolerance on the output shaft bearing is 25/1000" which seems a lot to me. So it seems the slack in the output shaft is in fact normal.
He couldn't help me with my noise in OD with TC locked. Nobody seems to have had that ever before.
I'll be talking to the shop that built the trans next.

Thanks again everyone.