Engine/Transmission (1998.5 - 2002) Truck wont downshift to 1st gear

[STPdieselhp]

I just installed a new valve body from suncoast with all new solenoids and the truck wont downshift when it gets hot. When you first crank the truck and it is cold it will downshift fine but when it get some heat in it then it wont downshift to first. All of the other shifting is fine. When I installed the valve body I didnt adjust the linkage due to the fact that I didnt know how. Do you think that could be the problem? It wont downshift to first even if I manually pull it down into first. Can anyone lead me in the right direction?



I think that I had the same problem before the valve body install.

 

[ironbutt]

STPdieselhp

Acording to the shop manual there are 4 posible things,

1,valve body malfunction.

2,governor circuit electrical fault.

3,front servo piston cocked in the bore.

4,front band linkage malfunction.

You need to see a trans man, unless you have the know how.

 

[STPdieselhp]

anyone think itmight be that the linkage isnt adjusted right. I just put a new valve body with new solenoids in.

 

[STPdieselhp]

Has anybody ever had this problem?

 

[STPdieselhp]

I have a trans fluid leak at the front of the trans. I pulled it out and installed a new input shaft seal and it is still leaking. I guess the front pump is no good. Do you think that this could cause my problem? It shifts fine through the rest of the gears. It will only go into first when you first crank the truck and pull it into gear. After that, it very seldom will ever go back down into first gear.

 

[ACoyle]

Have you checked the voltage. The lonk below is to another manufacturer's site, but, you may find the advice helpful.



http://www.dieseltrans.com/phpBB/viewtopic.php?t=171&highlight=2nd+gear+voltage

 

[Highfinance97]

If you shut it off, then start it again will it work???





Michael

 

[georgej]

Someone else had this problem recently and it was a transmission output speed sensor.

 

[STPdieselhp]

I have not checked the voltage. If I shut the truck off it still does it. Well whats weird is that tonight the trans was hot and I stopped to eat. I was in there probably 30-45 mins and came out and the trans will still hot. I put it in gear and it had first gear for about the first three times that I stopped and then it was gone again. Beats the hell outta me.

 

[Allnew2Me]

STP, I had a few minor issues with my Suncoast valve body a while back. Give Ernie at Suncoast a call, he does all the VB mods and he is a nice guy. Tell him what is going on with it.

800. 868. 0053

 

[STPdieselhp]

I noticed something today. After driving home from work I stopped at a gas station and cut the truck off and went in for maybe 3 mins. When I came back out and started the truck, I had first gear for the first couple of times that I stopped and then it was gone again. Wasnt in the store long enough for the trans temp to change so something had to have reset itself when I cut the truck off for those 3 minutes. Just thought that this info might help someone figure something out.

 

[Highfinance97]

I noticed something today. After driving home from work I stopped at a gas station and cut the truck off and went in for maybe 3 mins. When I came back out and started the truck, I had first gear for the first couple of times that I stopped and then it was gone again. Wasnt in the store long enough for the trans temp to change so something had to have reset itself when I cut the truck off for those 3 minutes. Just thought that this info might help someone figure something out.

The line pressure might be getting to high and it could be tripping the governer sencer.

(Maybe)

Did you check codes??









Michael

 

[STPdieselhp]

well i finally found my problem. The volts on pin 31 on the truck were at 5. 19 and should have been at 4. 5. I installed a 150 ohm resistor which dropped the volts down to 4. 73 and she works like new. All the headache for a $. 25 part. Thanks alot for everyone's help.