Joined: Apr 03, 2005 Posts: 271 Location: Chester County, PA
Posted: Sat Aug 07, 2010 9:37 am Post subject: T-90 Cluster Gear
Hi All,
To make a long story short, I ended up ripping out the transmission and xfer case out of my M38A1 earlier this summer. What was originally supposed to be a job of replacing some synchros, bearings, etc, turned out to be quite a project because of excessive wear - causing me to replace a substantial portion of the transmission.
Anyway, I've been trying to get this thing back together. I assembled the bearings into the counter gear and was ready to drop it in. However, I noticed that my cluster gear does not have the slots milled into it for the tabs of the one thrust washer. Looking around a bit, I found on Rick's T-90 rebuild guide that I'm not the only one that has this style cluster gear -- and he just says to bend the tabs inward. My problem with this approach is that this thrust washer could be spinning - which isn't a big deal, except the supposed-to-be-stationary side of the thrust washer is steel. Now, the thrust washer that came out of my T-90 is not the same style that Novak sent me. The one that came out is completely brass, and the pattern cut is slightly different (same diameter and thickness though). I cannot reuse the old one that came out as steel fragments are embedded in it from previous damage.
A couple of questions then: Has anyone else seen this? If so, what have you done? Like I said, I'm not too enthusiastic about having the steel side of the thrust washer spin. Have you found an all-brass thrust washer as I was describing? Also -- if anyone knows, why are there two different styles of cluster gears? I wouldn't be surprised if mine wasn't original to the jeep (as there was evidence of significant damage in that portion of the transmission which occured in a previous life).
Thanks! _________________ Bob Collins
1954 M38A1 MD79056
Joined: Jun 25, 2008 Posts: 583 Location: Kern Co.
Posted: Sat Aug 07, 2010 12:08 pm Post subject:
I'm no expert but common sense tell me that if the designers wanted it to be stationary they would use brass as a bearing surface which it sounds like they did. Maybe that washer needs to be replaced more often to prevent the damage you saw in yours.
Sounds to me like the steel washer is just going to transfer the impact and friction to the other side and maybe damage a more expensive part than the washer.
Personally, I would determine the correct configuration than mill the gear or make the washer if not too difficult. _________________ '53 M38A1 X2
Joined: Aug 26, 2005 Posts: 510 Location: North Carolina
Posted: Sun Aug 08, 2010 5:06 am Post subject: t-90
I have 3 trannys & transfers here I would love to get rid of..all 3 shift well as the transfer..
I would make it worth your while to come get one..
also have a rolling a1 chassic with engine that did run & drive awhile back you might be intrested in
Joined: Apr 03, 2005 Posts: 271 Location: Chester County, PA
Posted: Sun Aug 08, 2010 3:55 pm Post subject:
Sorry - I am not interested in another transmission. You're far away from me (I'm in PA this summer - Blacksburg VA is where I am during the school year). I have already replaced all of the parts that need replacing -- the only thing I am interested in now is finding an all brass thrust washer for the cluster gear in place of the one that is half steel half brass with metal tabs. Not interested in a frame + engine either -- I restored my M38A1 several years ago. I did not work on the transmission much because I was under the impression that the previous owner replaced a lot of the wear parts (which was not true).
In conclusion -- I would like to know:
1 - Does anyone else have this style cluster gear (without the milled tab slots)?
2 - If so, did you bend the tabs down on the standard steel / brass thrust washer as recommended per the T-90 rebuild guide thats posted online?
3 - Has anyone seen an all brass thrust washer for the cluster gear with no tabs? I cannot seem to find it everywhere I look....
3 - Why are there two style cluster gears? I know I am not the only one that has this -- this style difference has been called out on the T-90 rebuild guide.
I appreciate the offers -- but -- I am not interested in another transmission, nor am I interested in another cluster gear. I have worked through, analyzed, and bought all of the parts I need to make this thing work like new -- minus this all brass thrust washer. _________________ Bob Collins
1954 M38A1 MD79056
I may have missed something here but the front thrust washer I believe has a tab to mate it to the notch in the front end of the case. That should hold it still. All the T90's up thru 1966 called for the steel backed bronze front thrust washer. I did notice the ORD 9's for the M38 use the same part number washer 640409 but they only call it a bronze washer.
Which tooth counts do your cluster gears have? 33-26-19-14 or 33-27-19-14 or 35-26-19-14? _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
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