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I recently purchased an '88 Sunrader 21' with auto/od transmission. Once my speed reaches 60 mph or I am climbing a hill there is a vibration in the drive line; if I remove my foot from the gas pedal it goes away and resumes as I give it gas again. It is not noticable under 50 mph. I had the carrier bearing replaced and the drive shaft rebalanced but this vibration remains and I don't want to give a mechanic permission to try a shotgun approach to replacing more parts. The transmission shifts smoothly. Can anyone give me advice on what things to check before I leave on my first 2000 mile trip into the mountains of Colorado?

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Thank you Smokepolehall. This is a great way to learn how to keep our old Toyota Rv's alive. I got my first chance to take the Sunrader up towards Flagstaff to see how well it could climb. As I held a constant speed in either D or 2 the vibration seems to happen depending on how much gas I give it; less gas and it goes away (and I lose speed) and more gas it gets quieter even though the mph remains the same. Its like a specific power range of torque gets something shaking, more or less torque it goes away, and I think its coming from the transmission end. I'm sure I'm not explaining this very well but I very much appreciate your input. My mechanic had replaced 2 cv's at the same time he replaced the carrier bearing and had the drive shaft rebalanced. I'll have him check the trans seal bearing next.

Also, I had read in Forums about my overdrive kicking out at altitude. Sure enough mine went out at 3700' and did not return until I got back down to 3200'. I need to re-read all info about this to find a way to override the cutout. I would rather use my judgement so I could decend slight grades in OD and give the screaming engine a break while still shifting back to D or 2 for climbing and rolling flats. My entire upcoming vacation will be spent above 4000' roaming around western Colorado.

McShank

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I just returned from our first overnight and on the way back I noticed a new detail from the vibration problem. It still has the vibration at different speeds depending on how much gas I give it. But while going downhill at about 60 I wanted to give a break to the rpm's (no overdrive at higher altitude) and when I slid the trans into N the fibration became constant. I put it back in D and the vibration went away. It happens at all speeds over 57. Smokepolehall, if you see this let me know if this sounds like a particular part of the diff that's worn out. It goes to the mechanic Tuesday and hopefully a repair.

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In this section of the foums there is a pinned posted about rebuilding transmissions. Read it. He talks about the bushing in the tailshaft. If this is worn your driveshaft will wobble and cause vibration.

NOTE that regardless what Toyota says the bushing is replaceable.

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I have had the driveshafts balanced, carrier bearing replaced along with the cv's but my vibration is still there above 53 mph. Withn the next few weeks I will be bringing my 1 ton toy to a differential repair shop to take a look. He has expressed concern over the phone that if I need any new parts other than bearings, like punkin or ring/pinion, it might be difficult to find them. Has anyone located a source for theirs?

Seamus McShank

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Is the differential making noise? There really isn't much in there that will cause a vibration unless it's really trashed. Did they replace all of the u joints?

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Vibrations from the rear may be telling you it is time to change the universal on the drive shaft. I could use a little help form the members here too. I just signed up and am in need of some expertise with the 5 lug subject to failure prone rear. I want to go to a full foating 1 ton rear. Thanks, Matt

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Maineah;

All cv's plus the carrier bearing have been replaced and both sections of the drive shaft balanced. As far as noise, it does wind up a little song as mph's increase but nothing real loud; should I expect to have no noise at all? The differential shop I spoke to doesn't have the best overnight storage in a bad side of town so I am hoping to have my possible repair parts lined up for quick access. I assume Toyota no longer would carry these parts. I was also told in a prior posting that I could check the nose cone bearing in the transmission. Process of probable elimination. It rides smooth as silk below 50 mph but I cause a little road rage holding up traffic on state and interstate roads and I know it can and wants to cruise at 65. Thanks for any suggestions.

Seamus McShank

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Vibrations from the rear may be telling you it is time to change the universal on the drive shaft. I could use a little help form the members here too. I just signed up and am in need of some expertise with the 5 lug subject to failure prone rear. I want to go to a full foating 1 ton rear. Thanks, Matt

Howdy Matt.

This subject has been really covered here in several posts. Go to the search function in the Grey bar at the top of the forum,type in ' Full floater" and you will find numerous posts with all the info you desire. Hope this helps.

John

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Here is a new slant to the vibration. I have an 88 Buick Regal with front wheel drive and auto trans that had this type of vibration. I replaced both cv joints (twice) new ball joints and other stuff. Still had the vibration, took it to a trans shop and they said it was due to the torque converter, then said it was probably because of lack of power and suggested a tune up. Upon checking found the coil pack modulator was bad. Put in another modulator and the vibration left.

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A drive-line vibration is more of a buzz sound once you reach a higher speed. Once you hear it can get louder for a few seconds after you drop throttle. Universals are hard to see if they are bad when on the vehicle unless really really bad and usually the drive line must be removed to tell unless of course it is all ready on the ground from breaking.

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Maineah;

All cv's plus the carrier bearing have been replaced and both sections of the drive shaft balanced. As far as noise, it does wind up a little song as mph's increase but nothing real loud; should I expect to have no noise at all? The differential shop I spoke to doesn't have the best overnight storage in a bad side of town so I am hoping to have my possible repair parts lined up for quick access. I assume Toyota no longer would carry these parts. I was also told in a prior posting that I could check the nose cone bearing in the transmission. Process of probable elimination. It rides smooth as silk below 50 mph but I cause a little road rage holding up traffic on state and interstate roads and I know it can and wants to cruise at 65. Thanks for any suggestions.

Seamus McShank

Yes all rear have some noise and one that is geared that low will have a little more. What mean is a howl or a noise like roller skates on the pavement.

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Here is a new slant to the vibration. I have an 88 Buick Regal with front wheel drive and auto trans that had this type of vibration. I replaced both cv joints (twice) new ball joints and other stuff. Still had the vibration, took it to a trans shop and they said it was due to the torque converter, then said it was probably because of lack of power and suggested a tune up. Upon checking found the coil pack modulator was bad. Put in another modulator and the vibration left.

It is possible you have a missfiring engine, apply the breaks put it in low and give it the gas if it vibrates then you maybe on the right track that will eliminate the drive line.

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Maineah & Gulfstream Greg,

I tried the misfiring thing with the brakes depressed and no solution; a good idea but the engine runs smooth. I don't get very much time to work on the solution but hope I can find the answer before a planned long trip in September. One way I know beyond the sound and feeling in the floor is looking in the rear view mirror and watching the sink faucet image as it becomes very blurred at cruising 55 mph - and straightens out as soon as I let up on the gas or put the gas pedal to the floor. I think I have two more steps in the process of elimination - the nose cone of the transmission and trans mounts (already checked the motor mounts) and the punkin - ring/pinion in the diff. If I had a lot more leasure time I would be enjoying this more but with so many little upgrades on the list I seem to be stalled on this one. Thanks for your ideas.

Seamus McShank

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Does your transmission have ETC control? It should be able to do 55 with out the O/D on see if that makes a diffrence.

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Something you might also want to check is to see if the rear axle is is torqueing excessively under load. This rotation will will throw the driveline centerline outside the limits of what angle the u-joints can handle without vibration. Take a quick check of the spring shackles and front spring pivot bushings. If these get gushey, the rear axle assy could shift , giving you this problem.

Hope this helps.

John

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Finally "bit the bullet" and had a differential-only shop take the diff apart. New ring & pinion and bearing has eliminated the vibration problem and since this Toy is a keeper I am looking at the $1200 as a long term investment that had to be done. Going to the north rim of the Grand Canyon next weekend and expect no further problems in the driveline. I'm currently working on my vintage Kohler 2.5 generator (rebuild carb and new muffler) and the likewise vintage 11,000 BTU roof AC. Installed a hard start capacitor on the ac, the generator still doesn't sound quite right, but the ac did catch on low but stalled out when I tried medium setting. It seems even in the large metro area of Phoenix I can't find anyone to work on the generator unless I remove it and that looks like a major undertaking because of the way brackets were welded for support.

McShank

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Your vintage rooftop AC probably has an EER of 6, which makes it require over 1,800 watts... but that was when it was new. With age, compressors and blower motors draw more current. Wouldn't doubt that its using 2,000-2,400 watts now. And gensets dont get better with age either! No wonder it's stalling out.

If you replace your unit with a modern 10 EER AC, the same cooling capacity (11,000 BTU/h) will only require 1,100 watts to run. Well within the capabilities of your genset.

If you cant afford a new rooftop unit, ask a HVAC contractor what they'd charge you to replace your existing energy hog compressor with a modern one of the same BTU/h rating. But beware that you can buy a new window AC unit for less than the price of the compressor that's in it! Therefore, it's most economical to find a "donor" unit.

That might run you 200 labor and bump you to ~8 EER, reducing power requirement to 1,400 watts.

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Replacing the ring & pinion and bearing has cured the driveline vibration - its completely quiet until I let her get up to 65 mph and then I get just a little vibration and that could be the trans bushing or something else. I don't usually drive above 60 anyway so for now I'm a happy camper. I took her for a 4 day break-in trip to the north rim of the Grand Canyon trading the 113 degree temps in the desert for highs in the 70's. Next thing to tackle is to get the generator running better so I can run the roof ac while driving my way out of this heat.

Seamus McShank

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Thanks for all the info on this Forum.

I just purchased a 1987 Sunrader. It was very inexpensive and actually had a line of folks waiting to see if I would buy it or not. I got there first.

No time to check out everything or much of anything so it was buy it now or lose it. I bought it after driving it around the block.

Driving home was another matter. The Toy wanted to jump off the road the vibration was so bad. Off to my mechanic to see if he would work on her and used the list of items to check that I got from here.

MANY THANKS.

The problem was the carrier bearing. Bent and exceptionally wobbly. I had all the U-joints and the rear tranny seal replaced also. Basically, everything except the ring and pinion.

I pick her up this week but so far, so good. Also did complete tune up, tranny service and general maintenance.

You folks made all of this simple.

Thanks again,

Lou

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