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RD688s with Eaton 18 speed


masterwelder

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My truck is a 2000 RD688s Tractor with E7 400 and a Eaton Fuller 14909MLL transmission. My truck also has a REPTO (rear engine power take off). 
 

I’m taking the 9LL out along with the REPTO. I have a standard ETech engine bell housing to replace the REPTO engine bell housing. The new transmission will be a RTLO 18918B. 
 

My question is about the correct mounts and location. I’m wondering if someone has a RD with a factory Eaton 18sp that would be willing to share the vin so I can source the correct mounts/ transmission bell housing?

 

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i know the tranny mounts are in the same spot on the Eatons,, just like Mack tranny's.    The back boxes are different.. ......    RD 688-S/ 045719 Is a 2001 RD that i have worked on..   E-Tech with an 8LL..   This should be what you need to check and see if your tranny hangers are different..  No REPTO on this truck.. jojo

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Thanks Jojo. 
 

After reading your post I brought my 2001 RD688S dump truck with a 427 and 8Ll in to measure things up and compare. I was initially thinking I needed info from a truck with a eaton 18 in it but-
 

I see that both trucks have the mounts on the transmission bell housing. So I’ll need to make sure the new 18sp comes with the correct transmission bell housing. Other than that the only difference I see is because of the REPTO flywheel housing being about 4.5” longer than a regular flywheel housing, once it’s removed and replaced with the regular flywheel housing, the mounts will need to come ahead. It also looks like the frame side mounts are angled and by switching them left to right and right to left they may bolt in the same spot as the dump truck and line up with the new trans and flywheel bell housing. The transmission side mounts are the same on both trucks. 
 

 

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Thanks for posting again..  I would like to know what other differences you find, if any.  Plus it is good for future questions about this..  are you saying the REPTO housing is 4.5" longer measuring at the seem on the engine block?  if so then the tranny is set back 4.5 inches more than your '01 RD?  which may result in a drive shaft change..  jojo

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Unfortunately,  I have No practical knowledge of REPTO's..  I have seen them and made a few repairs many years ago,  But I have forgotten all of it..  I'm just glad that I have a Mack svc. manual on REPTO's,, in the case I have to do a repair, or post the info here..  P.M. me if you need me to send a picture of the book and its pages..  Jojo

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  • 3 weeks later...

Stopped in at the shop quick between pushing snow into piles and the bell housing was on, flywheel was back from resurfacing and they were in the process of relocating the transmission mounts. They hoped to have the trans in by the afternoon and driveshaft ready to be sent out to be lengthened. 
 

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Turns out the transmission side mounts are different. 
 

I was able to get the numbers off the transmission mounts on my dump truck. I think the frame side mounts are the same but will do some measuring in the morning. 
 

The transmission mount part numbers I believe I need are, 158GB4553A and 158GB4554A. 
 

So we are at a standstill for now. 

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Thanks Joey. 
 

My truck has a single frame. I’m unsure  if the inner frame dimensions are the same as a double frame truck? In other words did Mack maintain the inner frame dimension or did it get narrower as they added layers of frame. 
My RD dump is double framed. I wonder if the same mounts are used on a single frame truck.

I really wish Mack would  give us access like I have with caterpillar on my heavy equipment. In the caterpillars SIS system I can go in with the Vin number for any piece of equipment and get the complete breakdown right to the bolt and nut specifications. Saves a lot of phone calls to the caterpillar parts department you can do all of your own research. 

I would love to run a vin number of a double frame RD against a single frame RD with a E7 and Eaton manual trans to see if they use the same frame side and trans side mounts. 
 

I think I found a single frame RD vin number with an E7 and Eaton, they’re not that common at least on TruckPaper right now. 

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Well got my Mack frame book out and might’ve answered my own question about the single frame versus double frame, triple etc.
 

According to the book a double frame truck will have the second frame on the inside of the main frame. Any additional layers after a double will be to the outside of the main frame. 
 

With that being said it would make sense that mounting brackets would be narrower on a double frame truck than a single frame.  Or  a spacer is used to make up the space, similar to having an inner rail on a single frame, then the same brackets can be used regardless of the frame thickness. 
 

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Edited by masterwelder
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Me too!

New trans and the removal of the REPTO. The REPTO is kinda heavy- 3 good size gears plus several bearings and it took two oil lines. Aluminum housing but it all ads up. No doubt took HP to turn even if not connected to anything. Hope my oil pressure comes up a little, I was on the lower side when hot. 

I wanted the REPTO out the day I bought the truck. When the 9ll started to occasionally slip out of 3/7 gear I took the opportunity to get rid of it and slip in the 18. Turns out the clutch was in need and the rear main was leaking so I would of been in there soon anyway. 

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When I was with the construction co. In  Scarborough Maine,. The last tractor that was assigned to me was a '97 RD..  E-7 400,,, 18 spd. Mack tranny,,, Mack Rears, 4.17 I think.. it would out pull the new E-Tech 427's...  At the time..  Jojo

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