spassey

For years we have seen cresent type pumps push the inner gear into the cresaent causing premature pump wear and even conv hub wear I just wonder how that is going to to with the cutback system deleted oout of our state of the art allison trans. unplug the modulator on a thm 350 for better shift and all the sudden we get about 8 passes and the pump is winning and pucking oil out the front seal??????

spassey

This is more technical than previous post so bare with me. High capacity mode on Ford E40D and 4R100's has it’s toll on outer pump gear because of being a cam and lobe type pump the outer gear likes to push to one side and eventually show premature wear. The pump in a Allison is a gear type pump with a crescent or quarter moon that the inner gear push oil into to create pressure. These type pumps almost always have a pressure regulator valve to regulate pump pressure with in the means of capacity for the transmission. The Allison in the Duramax on the other hand runs a static line and give you a cutback pressure so this type of wear doesn’t occur. Cutback occurs on lockup of the converter and in fifth gear. Many alterations have been done to keep the conv lining from slipping but are we going to see a lot of premature pump problems? This transmission brings lockup on in tow mode immediately after the 1-2 upshft and line cutsback . Maybe this will clean up what I was trying to imply

Shovelhead

Even though I didn't understand a single word of your post
I thought I'd jump in and say Hi, and welcome to the DTR. ;D
The ins and outs of them Auto-tranny things just ain't my bag.
That's why I'm glad there's people like you that understand them.

Ed

spassey

well ed just trying to bring up the awareness of those considering high line in automatic transmissions some trans you can get away with alot and others you just cant nice truck

Lary Ellis (Top)

Welcome to the site! I wish I could offer some helpful information for you on this issue, but I know little about the Allison Transmissions.

If you haven't done so already, Check out ATS transmission specialist they have their own forum now and might be able to jump right in their and help you on that issue.

I am not trying to run you off here as someone may come along that can help, but I will put the URL up here for the ATS forums in case you want to go take a gander at them.

http://forums.atsdiesel.com


Once again I want to say it is nice to have you with us!

59Dsul

Makes me glad I drive a stick ;D<br>Seriously though, is the auto in our trucks likely to have this failure? I'm dumb as a box of rocks about automatics

Lary Ellis (Top)

[quote author=59Dsul link=board=7;threadid=9682;start=0#92537 date=1042676777]<br>Makes me glad I drive a stick ;D<br>Seriously though, is the auto in our trucks likely to have this failure? I'm dumb as a box of rocks about automatics <br>[/quote]<br><br> No sir that is not one of the more common failures in the Chrysler transmission in the dodge truck, they do have their own shortcomings though and hopefully the new 48RE they just came out with, will address these issues properly.<br><br> The main problem is that these diesel engines have so much power at low rpm, the transmission as a stock unit just can't keep up with it. That is where people like ATS, DTT and suncoast all come in with specialized products to help work that type of power curve.<br><br> If you ever do go with an automatic, call one of those people for advise as they can make it a much stronger unit.

spassey

well i just got on this forum alot of bashing of product when the real issues are undermined . thats all sorry if i affend anyone.

Shovelhead

No offence taken. <br>You're just alot more knowledgeable about auto trannys than some of us, but we're always willing to learn. 8)<br><br>Ed

59Dsul

No apology necessary. I agree, with the amount of aftermarket equipment out there, it's easy to &quot;bolt-on&quot; all kinds of stuff. I'm guilty of that. It's good to read about the internals of these trucks. It makes me think once in a while, I've been told that's good for a person ;D, andy<br>