Trans and off road...

[PDXDave-SMB]

I have a transmission question that I think applies to this group....

We were out over the last couple days and on one pretty steep hill climb I had to stop and engage the front axle.
Trying to restart it took a LOT of throttle to get moving again (22psi) and after that my trans temps went up pretty sharply.
They hit 242 before I said screw this and turned around and headed back down the hill.

My trans fluid is at the proper level, looks and smells good and isn't burnt.
The last full trans service was done at 77k and we just turned 100k

I know we're heavy @ 10750 loaded and ready to camp, but with the 4.11s and a mild tune in the programmer, I'd think I'd have the oats to do that without such a heavy foot.

Now I'm planning a trans service asap, the addition of a large, external cooler ans possibly a deep dump trans pan.

Am I missing something?

 

[Twoxentrix]

Check out post #14 - The Derale has completely removed all my Trany anxiety & it turned out to be a relatively simple install...I agree you shouldn't have had to push the engine that hard to get moving (assuming you were in 4 low). I have 4:56 and a little over 1k lbs on you, but I've never had to exercise the pedal to that extent to get going on a steep grade.
https://www.sportsmobileforum.com/forums/f33/claimed-mishimoto-6-0-trans-cooler-31033-2.html

EDIT: Pic's on page 338 (post 3380 & 3382) in this thread:
https://www.sportsmobileforum.com/forums/f19/what-did-you-do-to-your-smb-today-3234-338.html

 

[PDXDave-SMB]

Copy that.
Good info...
The temps I can fix.
My biggest concern is how much throttle it's taking the get her moving off road.
I'm hoping my stock, 100k mile converter isn't shitting the bed.
After researching a ton on the 5r110w the lock up of this converter is pretty weak.

 

[carringb]

I can’t think of any scenario where it should require 22 psi to get moving.

Did you happen to manually a lower gear? If you select 3 or 2, it locks out lower gears. It uses the gear only.

 

[superduty]

Were you in 4 low?

In 4 low it should have all sorts of neck snapping torque.

 

[Glenn P.]

I was wondering about the 4 low and what gear too. I do find it odd that if you select 3rd gear that's all you get, not 1-3, just 3. I also found that out wondering why my van was struggling to get going off road.

Now as far as trans temps, yes, I typically see temps in that range on my 2005 Quigley 6.0PSD when off-roading under load. I also have an Atlas 40 tune and I even have the Mag-Hytec extended capacity trans pan. Off roading, low range in deep sand for me is what does it, ohh and add a decent size utility trailer packed with my ATV, firewood and water. I'd say that is really close to your uphill experience. Also, when off-roading like that, your speeds aren't overly high so the airflow we depend on when cruising down the highway is gone.

 

[CDACamper]

Another vote to double check you are in first gear. It sounds to me like you are starting off in second or third. I am close to 11k fully loaded and I can creep forward in first gear and low range on a steep grade at idle speed. 4R100 with 4.56 gears and 305 70 16 tires.

 

[JoeH-SMB]

In my experience, a steep grade in 4wd hi will get the transmisson hot in a hurry.

But if this is a 6.0 psd sounds like turbo lag to me, despite the tune in whatever programmer you have. A custom tune would get that turbo to light up.

 

[Orv-SMB]

I would try your transmission gear ranges on flat ground and make sure they're all working as expected. In particular there are certain failure modes in the AODE/4R70/4R75 family of transmissions that can cause them to bind in manual Low and start in second gear in Drive.

 

[PDXDave-SMB]

Ordered a Derale Hypercool and am putting it in on Monday.

As far as gears, ya caught me... I was not starting out in first.
A quick diagnostic drive got me straightened out.

Joe H, you're correct as well, as the boost lag in this thing is horrendous.
I need to find someone in my area to sit down with and build a tune with.

 

[superduty]

Were you in 4wd low range?

 

[Twoxentrix]

Ordered a Derale Hypercool and am putting it in on Monday.

:d3: Removes a key 'frustration' from those 'heat temp urgencies' which develop at the most inopportune time.