Farm Equipment - 7045 PS trans brake

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7045 PS trans brake

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=137887
Printed Date: 08 Nov 2025 at 10:41pm
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Topic: 7045 PS trans brake

Posted By: Carl(NWWI)
Subject: 7045 PS trans brake
Date Posted: 28 Apr 2017 at 6:22pm

On our 7045 power shift, when you try to shift the high or low lever it just grinds. You have to shut the tractor off to shift it. Looking through a service book I have here but it barely covers the trans brake. I've read some other posts where people had to replace cables and bushings, but ours doesn't have a cable, it's just the steel rod. Always worked very well, then one day just quit working. I have a pressure guage hooked up the what the book shows the trans brake port. Reads zero pressure with pedal depressed.

Hopefully somebody can help.

Carl

Replies:

Posted By: Orange Blood
Date Posted: 28 Apr 2017 at 6:41pm

There is no cable on a Power Shift tractor, the clutch rod as you indicate routes over to the power shift valve body. It must be adjusted correctly just like a cable in the power director. Does your kick down work correctly, I.E. from 5th or 6th, down to 4th when depressing the clutch?

The trans brake function is accomplished by applying two clutches at the same time B1 and C2 clutch. These are applied in the last 20% or so of clutch pedal travel, do you feel a definite change in clutch pedal resistance when pushing that last 20% or so? Put your gauge on the B1 test port, with the pedal depress all the way to the floor you should have around 30 psi, depending on some variables. If you don't have any slipping in any gear position, then you have a sticking/blocked valve, or an out of adjustment clutch rod.

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Posted By: DrAllis
Date Posted: 28 Apr 2017 at 7:00pm

Probably the snap ring has come off of the end of the inching spool. A common problem for Power shifts of that vintage. Remove the valve assembly and just assemble things and put a spot weld where the snap ring goes. It's fixed for good.

Posted By: Carl(NWWI)
Date Posted: 28 Apr 2017 at 10:35pm

Thank you both for the help! Checked for pressure at B1, zero psi, even after adjusting linkage. Removed and disassembled valve, and as the Dr. stated, the snap ring was gone!!

Posted By: DrAllis
Date Posted: 29 Apr 2017 at 7:44am

Like I said, that snap ring breaking eventually happened to every machine that had that design. Re-assemble the parts, compress the spring and clamp with needle nose vice grips, put a spot of weld on the snap ring groove and you are permanently fixed. The weld doesn't have to be pretty, just something to keep parts where they belong.