transmission question

[shinta]

Ok so what rpm should I be at with 4in lift and 33x12.5 while driving at 70mph. The reason iam adking id because I tried a long highway drive this weekend. Rpm wbere screamn at 3300. It seems high. Also once I got up to 70 I noticed the rpm never dropped. Dods that mean my x isnt locking out. If it does iam planning on chanw out the solenoids this weekend. With that ive read about some shift kit upgrades. Is this something I should and if so which one should I get? Thanks

 

[natenkiki2004]

On mine, it locks up around 45-50MPH but mine was rebuilt and upgraded, things might have deviated from factory settings. With larger tires, you'd be rolling faster than your gauge says. With 235/75-15 tires, I believe I get around 2200-2500RPM at about 65MPH. I think you'd almost have to lock up to be going 70MPH. I've screamed up to 3500RPM before lockup on a slight incline, maybe doing 40MPH, I don't think there's enough "oomph" to get up to 70 without lockup, even on flat land.

 

[shinta]

So after hitting 70 and maintaining that speed shouldn't my rpm drop a little bit. Or would it stay at 3300

 

[natenkiki2004]

If you're locking up, it would stay that high because your engine is linked directly to your transmission's output speed.

3300 does seem a bit high but then again, I haven't gone 70MPH and I don't have tires as large as yours (extra rolling resistance).

 

[shinta]

Ok. Thanks.

 

[shinta]

So I was just thinking when I change from drive to od there should be a change right?

 

[Gadget X]

Is your speedometer accurate? If your speedometer is still as it was before the tire size increase, it should read about 70 at 2300-2500 rpm. If your speedometer is reading 70 at 3300 rpm, I think you have no lockup or overdrive, and you are in 3rd gear. Both of those functions are controlled by solenoids in the valve body, which ARE known to go bad. An easy way to check for lockup function is to "tap" the brake pedal while maintaining a steady highway speed. If you have lockup, the rpms will jump up about 300-400 rpm when you touch the brakes. You have to drop the valve body to change the solenoids, but it's fairly easy. If that is your problem, you'll be up and running again in an afternoon! Good luck with it!

 

[shinta]

Yes it reads correct. I changed out the plastic gear a couple months ago. When I get off duty tomorrow ill take it out to the highway and give that a try. I figured thats what it was but I like to run things by before ever starting something. Thanks.

Does anyone have a recommendation for brand of solenoids so I can start price checking. Iam also going to try the shift kit. Does anyone favor a certain one.

 

[Gadget X]

Check transmissionpartsusa.com .I think they're about the cheapest place to get good parts for a good price.

 

[shinta]

Awesome thank you.

 

[shinta]

Opened up the trans pan found this. Any ideas. Iam freakn out.

 

[natenkiki2004]

Kinda looks like a pin that holds something in place.

I finally checked my RPM's at 70MPH, I was a pinch under 3,000, maybe 2850 or so. That's with 235/75-15 tires.

 

[shinta]

Lol thanks. Actually I think it belongs to the old modulator that I replaced. I cant remember but I want to say it was missing when I replaced it.

So I decided to change my 3/4 solenoid because following Mayjan s advice I noticed I wasnt shifting out of 3rd. So I picked that up as well as a new filter and droped the pan when I got home. And guess what the first thing I noticed was. Ill just tell yall cause no one would guess it anyway. One of the wires comming off the 3/4 solenoid was smashed between the pan and the tranni. Iam talkin flat as paper! So I cut out the flat wire put in a new one installed the new 3/4 because why not and closed her up. Now at 70 iam lookn at about 2800 and od it was like 2300. So iam pretty happy now!.

But a new question. When in od slowing down, at about 45 the truck shutters. Is this normal or do I need to learn h I w to properly drive in od?

 

[shinta]

Here it is. Flat as a board.