Transmission Leak

[Petro]

Temperature today was +11 F and the sun was finally shining. I had not run the engine or Onan for a couple of months so I decided to run it out of the garage and warm both up. I don't take it out on the highway when the roads are full of salt.

When I ran it out of the garage the transmission fluid started dripping on the driveway. I did not warm it up in the garage do to my fear of exhaust asphyxiation. I had a trail out the garage door. I rolled under the transmission and it appeared to be coming out near the top and running down the driver side. As the tranny warmed up it quit leaking. I lost about a qt of fluid. It is Synthetic fluid.

My questions are as follows;

1. Should the tranny be warmed up when it is this cold before it is moved?

2. Do I have a problem that needs to be checked out by a Allison shop?

3. Perhaps I should just move to a warmer climate?

I have never had to add fluid and it was fine when I put it away in October.

I am hoping someone with experience with cold temperatures will jump in here.

Thanks;
Don

[Petro]

Temperature today was +11 F and the sun was finally shining. I had not run the engine or Onan for a couple of months so I decided to run it out of the garage and warm both up. I don't take it out on the highway when the roads are full of salt.

When I ran it out of the garage the transmission fluid started dripping on the driveway. I did not warm it up in the garage do to my fear of exhaust asphyxiation. I had a trail out the garage door. I rolled under the transmission and it appeared to be coming out near the top and running down the driver side. As the tranny warmed up it quit leaking. I lost about a qt of fluid. It is Synthetic fluid.

My questions are as follows;

1. Should the tranny be warmed up when it is this cold before it is moved?

2. Do I have a problem that needs to be checked out by a Allison shop?

3. Perhaps I should just move to a warmer climate?

I have never had to add fluid and it was fine when I put it away in October.

I am hoping someone with experience with cold temperatures will jump in here.

Thanks;
Don

[lyledavid]

Don. A vehicle sitting for two months may have allowed the trans. fluid to drain from the torque converter back into the transmission pan and when you drove the unit out of the garage before the trans pump refilled the torque converter it probably pushed oil out of the transmission breather causing the leak. Warm up and check the trans level and refill then start and check in a month or two and let the unit warm up and recheck. After you let the unit set for the time check and see if your trans is overfull before starting.
You and yours have a Happy New Year tonight.
Lyledavid AKA Rotweiler

[oemtech]

Don,

I think lyledavid is correct. When I changed my fluid to Mobil 1 Synthetic it took almost 14 quarts. Normal refill is 12 according to the manual. So, I can only assume that the torque drained back to the pan as it had sat for almost a month. Also, the minus temps will effect the viscosity of the fluid.

[Max Hubrich]

Don -- Option #3 is the best solution . The torque converter should normally not bleed down. Just watch your level closely. You might even have to crawl underneath the coach, wipe it all down good, Get a good flashlight and have grandmaw Bev hand you a few cookies, crank up the rig-- eat cookies and watch where the fluid is coming from. Then tell us what you found


Happy new year,

[Petro]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Max Hubrich:
Don -- Option #3 is the best solution . The torque converter should normally not bleed down. Just watch your level closely. You might even have to crawl underneath the coach, wipe it all down good, Get a good flashlight and have grandmaw Bev hand you a few cookies, crank up the rig-- eat cookies and watch where the fluid is coming from. Then tell us what you found


Happy new year, </div></BLOCKQUOTE>

Happy New Year to you also Max. If I keep eating Grandma Morgan's cookies I will not be able to get under the rig.

I will wait for warmer weather and check it again.

[Full-Timers]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by lyledavid:
Don. A vehicle sitting for two months may have allowed the trans. fluid to drain from the torque converter back into the transmission pan and when you drove the unit out of the garage before the trans pump refilled the torque converter </div></BLOCKQUOTE>I would think the motorhome would not move with no fluid in the torque converter.
I have never heard of a torque converter draining back into the pan.
However I have no explanation to why it leaked.

[M&EM]

I experienced same as Oemy when changing second round of synthetic fluid replacement. MH had been sitting for several months. An overnight draining yielded more then 14 qts.

This was quite a bit more then the 12 qts drained hot the first time using the same over night procedure.
I conclude that the torque converter and cooling lines must have drained....

Marty

[DriVer]

Guys you know what will drain back into the pan? The fluid in the tranny cooler and the lines. I don't believe it is possible for the torque converter to drain down, In order to bring our synthetic levels up high enough we have to drain and refill the tranny twice. The reason for this is because the converter does not drain down.

Dale, I drained and added about ~13 quarts of fluid when I did mine.

I suggested that the viscosity of the fluid at the time may have not allowed the fluid to flow quite as rapidly as it normally does when warm and this may have over pressured the system to some degree. Pent up pressure vented much like a volcano. Once the fluid began moving in the system all was well again and no further leaks were observed.

I am a bit dismayed in presenting this theory because synthetic transmission fluid flows well at low temperatures much better than Dexron. Amsoil Torque Shift fluid will pour at -67° below zero. +11 is relatively a heat wave in comparison.

Now you can always get a nice quart of Transynd from "Oemy's UP Performance" rather than having to buy a gallon of the stuff which you may never use.

[Petro]

Update;

This morning I called a Workhorse/Allison service center in our area. After explaining my problem to the tech, he also suggested it was either a sticking pressure regulator or a iced up vent. He told me not to worry but take the rig out on the road, warm it up to normal, and recheck the level. If it does it again I should take it in and have it checked.

Interesting Note

Being familiar with the temps in our area he suggested it would be better for my rig if I did not start it up during the cold temperature months. Letting it set for 3 months with out running it was better than trying to start it up when it is so cold. With all the salt on the road in the winter months and my fear of rust on the under carriage, idling does not bring up transmission or engine temperates enough to dissipate moisture. My new policy is to not start it up during the months of DEC, Jan, & Feb unless I am heading out on a trip.

Thanks for all of your replies;

Don

[exrench]

[QUOTE]Originally posted by Petro:
Temperature today was +11 F and the sun was finally shining. I had not run the engine or Onan for a couple of months so I decided to run it out of the garage and warm both up. I don't take it out on the highway when the roads are full of salt.

When I ran it out of the garage the transmission fluid started dripping on the driveway. I did not warm it up in the garage do to my fear of exhaust asphyxiation. I had a trail out the garage door. I rolled under the transmission and it appeared to be coming out near the top and running down the driver side. As the tranny warmed up it quit leaking. I lost about a qt of fluid. It is Synthetic fluid.

My questions are as follows;

1. Should the tranny be warmed up when it is this cold before it is moved?

2. Do I have a problem that needs to be checked out by a Allison shop?

3. Perhaps I should just move to a warmer climate?

I have never had to add fluid and it was fine when I put it away in October.

I am hoping someone with experience with cold temperatures will jump in here.

Thanks;
I had the same experience in exactly the same circumstances in Dec/07 and have had no further occurance.Following this,I have let the engine idle for a few minutes before moving the MH.From a historic perspective,when I changed over to Transynd at2000 Miles,I drained 16 litres and replaced a like amount and this seems like more than others have reported.The dipstick shows the level to be correct. My conclusion is that I am seeing a greater than average drain back from cooler lines etc.As others have said,don't panic and the oil loss was probably much less than the quart that you estimated.

[bdaball]

Petro,
Leave the cover on and forget it until spring!

[John350]

This may or may not apply. I come accross a GM Bulletin # 03-07-30-054 dated 10-28-03 stating that on cold temps, Trans fluid may come out of the vent on the Allison 1000 trans. Root cause was a non vented dipstick. The updated dipstick has a GM part number of 15115171. I found this on Alldata under 2003 Yukon XL 3500 There was a bulletin referencing the Allison trans

John.