having troubles with trany geting out of 3rd gear

[Diesel60]

i would really apreciate if some one could help me with this issue i have a 1995 suburban 6.5 diesel with an automatic trany i had a vacation get away for the week end drove for 1,000 miles give or take it worked fine i had just instaled the new fsd heat sink from ssd i got to new mexico and desided to tow a car home (70 dodge dart gts) while pulling the car for an hour the tranny decided to not shift into second or third gear while going up a hill i it will take off on first but wont shift and it will go on reverse. got the trany serviced and took off again and it did the same thing only when the trany oil gets hot will it not shift i would really apreciate any kind of help am stranded in new mexico

[6.5LSASQCH]

Is your rig 4WD? I had a similar deal really far from home as well and what it was with mine was the transfer case ended up having to get it replaced. There is a spring clip in the tailshaft housing that holds the output shaft from the transfer cases in place and the gears properly meshing. When that clip brakes (I guess this is common in our 95 suburbans) that shaft bounces in and out and it feels like you are going in and our of gear and that it just down shifted and then up again when you slow down. What is happening is that the gears on the shaft are just barely biting and you are grinding them to a pulp, that is if this is what is happening. You will also notice a small vibration. Pull the rear DS and then 4 bolts holding the tailshaft cone, if the clip is broken it should be in there in pieces. It will take a bit of time but it might be worth a look. Do you know what kind of temps your truck is running?

Like I said I thought I was losing third and I was 600 miles from home on a hunting trip so i feel your pain to make things worse I was in Wisconsin and it was COLD. Good luck and let me know how it goes.

[JD_countryboy]

When my torque converter went bad, it startted slipping too much. THe slipping would cause it not to go into 4th once it was warmed up. cold it was fine. After a while, it started downshifting from 4th to third once it warmed up. i was never pulling anything though, never trusted the tranny cause of the slipping. I dumped a bottle of Lucas Trans Fix in the tranny, and let it sit and idle for about 30 min. Right as soon as i took the truck out it was TOTALLY BETTER. THis did quick fix the tranny and i did tow a little with it. Only used it for 3 or 4 months and then totally rebuilt the tranny and put in a new torque converter. The Lucas Oil Transmission Fix i have found in Napa And most major parts stores, Tractor supply Company, and some other places. It was $13 a quart, I used 1 quart. Bottlke says you can add 2 quart for severly worn trannys. Stuff it really thick and kinda hard to squeeze outta the bottle, but it did work for me.
Its a cheap quick try since its what your lookin for.

[Diesel60]

sorry guys i kind of staited my problem wrong my truck (1995 suburban 4x4 4.10 gears automatic ) what happens is that i can drive the truck for like 80 - 100 miles of distance it drives fine towing or not and then just out of no whare it will just drop down to first gear and just stay thier you can keep on driving about 45 miles per hour and rev the enging till it redlines but! it wont shift into any other gear after that you can keep on trying you can try shifting it manually but it wont shift into another gear. then if you let it cool off for like 2-3 hours or so it will work fine i had never had this problem it is my daily driver so i am kind of confused at wat to due since it is so far away from home i am from south texas and the truck is in new mexico the truck had its trany rebiult like 8 months ago ! the mechanic that serviced it told me that it seemd that nothing looked wrong mechanichaly that it could be a sensor inside the tranny? like i said i would apreciate any suggestions or comments on what to due !!!!

[runrucker]

I experienced this and it turned out to be the shift solinoid in the trans. Only happened when towing with the trans temps climbing. Hope this helps!

[Diesel60]

yea whare is that shift soliniod located it seems to me like nothing is wrong with the tranny am going to try and change that solenoid about how much would it cost to change and another thing is it bad that my truck runs like at 190 degrees through 210 degrees ? thanks alot guys ive been learning alot more out of my truck out of ure suggestions !!!!!!

[6.5LSASQCH]

thats the proper temp to be running at if you are taking engine temps. Tranny can go a little higher 240 max.

[runrucker]

the shift solinoids are located inside the trans. The one I had to have replaced controlled 2nd to third. My truck would shift up to 2nd and go no farther, it would only go back to 1st after sitting shut down long enough to cool off. Shop diagnosed mine and replaced it. It's been fine for over two years.

My temp range is between 185 and 210 when I tow.

[Diesel60]

hey thanks for the help kenny apreciate it am going to new mexico like in about 3 weeks i bought both shift sensors from one of muy buddies hear in mcallen texas cost of them was 40 bucks i will change these once i get overthier i hope i dont have a hard time i really apreciate all the help you guys have given me i might think about selling my suburban its in good shape but i got a new truck and might sell this one i am still thinking about it since it was reall good to me like i said guys thanks a million i will try to get to the bottome of this

[JD_countryboy]

OK, now i have a different suggestion, but more questions first. Does your speedo still work? My parents had the same problem with their 93 Chevy van, 350 gas engine. They would lose there speedo, tranny downshift and no more tranny shift. It was the ignition switch. Found one of the terminals was burned. cold it was ok, but warm up and it would act up. THey wre lucky, only 10 miles from home. Just a thought.

[Diesel60]

the speedo still works whats wierd is that i caled my uncle back in new mexico said he drove the truck for a distance of about 150 miles pulling a loaded trailer through hills and the truck was working fine he told me it would shift into gear so thats kind of wierd am breaking my head i shure hope its the soleniods